What Are The Steps Of The Scientific Method?
Julia Simkus
Editor at Simply Psychology
BA (Hons) Psychology, Princeton University
Julia Simkus is a graduate of Princeton University with a Bachelor of Arts in Psychology. She is currently studying for a Master's Degree in Counseling for Mental Health and Wellness in September 2023. Julia's research has been published in peer reviewed journals.
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Saul McLeod, PhD
Editor-in-Chief for Simply Psychology
BSc (Hons) Psychology, MRes, PhD, University of Manchester
Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.
Olivia Guy-Evans, MSc
Associate Editor for Simply Psychology
BSc (Hons) Psychology, MSc Psychology of Education
Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.
On This Page:
Science is not just knowledge. It is also a method for obtaining knowledge. Scientific understanding is organized into theories.
The scientific method is a step-by-step process used by researchers and scientists to determine if there is a relationship between two or more variables. Psychologists use this method to conduct psychological research, gather data, process information, and describe behaviors.
It involves careful observation, asking questions, formulating hypotheses, experimental testing, and refining hypotheses based on experimental findings.
How it is Used
The scientific method can be applied broadly in science across many different fields, such as chemistry, physics, geology, and psychology. In a typical application of this process, a researcher will develop a hypothesis, test this hypothesis, and then modify the hypothesis based on the outcomes of the experiment.
The process is then repeated with the modified hypothesis until the results align with the observed phenomena. Detailed steps of the scientific method are described below.
Keep in mind that the scientific method does not have to follow this fixed sequence of steps; rather, these steps represent a set of general principles or guidelines.
7 Steps of the Scientific Method
Psychology uses an empirical approach.
Empiricism (founded by John Locke) states that the only source of knowledge comes through our senses – e.g., sight, hearing, touch, etc.
Empirical evidence does not rely on argument or belief. Thus, empiricism is the view that all knowledge is based on or may come from direct observation and experience.
The empiricist approach of gaining knowledge through experience quickly became the scientific approach and greatly influenced the development of physics and chemistry in the 17th and 18th centuries.
Step 1: Make an Observation (Theory Construction)
Every researcher starts at the very beginning. Before diving in and exploring something, one must first determine what they will study – it seems simple enough!
By making observations, researchers can establish an area of interest. Once this topic of study has been chosen, a researcher should review existing literature to gain insight into what has already been tested and determine what questions remain unanswered.
This assessment will provide helpful information about what has already been comprehended about the specific topic and what questions remain, and if one can go and answer them.
Specifically, a literature review might implicate examining a substantial amount of documented material from academic journals to books dating back decades. The most appropriate information gathered by the researcher will be shown in the introduction section or abstract of the published study results.
The background material and knowledge will help the researcher with the first significant step in conducting a psychology study, which is formulating a research question.
This is the inductive phase of the scientific process. Observations yield information that is used to formulate theories as explanations. A theory is a well-developed set of ideas that propose an explanation for observed phenomena.
Inductive reasoning moves from specific premises to a general conclusion. It starts with observations of phenomena in the natural world and derives a general law.
Step 2: Ask a Question
Once a researcher has made observations and conducted background research, the next step is to ask a scientific question. A scientific question must be defined, testable, and measurable.
A useful approach to develop a scientific question is: “What is the effect of…?” or “How does X affect Y?”
To answer an experimental question, a researcher must identify two variables: the independent and dependent variables.
The independent variable is the variable manipulated (the cause), and the dependent variable is the variable being measured (the effect).
An example of a research question could be, “Is handwriting or typing more effective for retaining information?” Answering the research question and proposing a relationship between the two variables is discussed in the next step.
Step 3: Form a Hypothesis (Make Predictions)
A hypothesis is an educated guess about the relationship between two or more variables. A hypothesis is an attempt to answer your research question based on prior observation and background research. Theories tend to be too complex to be tested all at once; instead, researchers create hypotheses to test specific aspects of a theory.
For example, a researcher might ask about the connection between sleep and educational performance. Do students who get less sleep perform worse on tests at school?
It is crucial to think about different questions one might have about a particular topic to formulate a reasonable hypothesis. It would help if one also considered how one could investigate the causalities.
It is important that the hypothesis is both testable against reality and falsifiable. This means that it can be tested through an experiment and can be proven wrong.
The falsification principle, proposed by Karl Popper , is a way of demarcating science from non-science. It suggests that for a theory to be considered scientific, it must be able to be tested and conceivably proven false.
To test a hypothesis, we first assume that there is no difference between the populations from which the samples were taken. This is known as the null hypothesis and predicts that the independent variable will not influence the dependent variable.
Examples of “if…then…” Hypotheses:
- If one gets less than 6 hours of sleep, then one will do worse on tests than if one obtains more rest.
- If one drinks lots of water before going to bed, one will have to use the bathroom often at night.
- If one practices exercising and lighting weights, then one’s body will begin to build muscle.
The research hypothesis is often called the alternative hypothesis and predicts what change(s) will occur in the dependent variable when the independent variable is manipulated.
It states that the results are not due to chance and that they are significant in terms of supporting the theory being investigated.
Although one could state and write a scientific hypothesis in many ways, hypotheses are usually built like “if…then…” statements.
Step 4: Run an Experiment (Gather Data)
The next step in the scientific method is to test your hypothesis and collect data. A researcher will design an experiment to test the hypothesis and gather data that will either support or refute the hypothesis.
The exact research methods used to examine a hypothesis depend on what is being studied. A psychologist might utilize two primary forms of research, experimental research, and descriptive research.
The scientific method is objective in that researchers do not let preconceived ideas or biases influence the collection of data and is systematic in that experiments are conducted in a logical way.
Experimental Research
Experimental research is used to investigate cause-and-effect associations between two or more variables. This type of research systematically controls an independent variable and measures its effect on a specified dependent variable.
Experimental research involves manipulating an independent variable and measuring the effect(s) on the dependent variable. Repeating the experiment multiple times is important to confirm that your results are accurate and consistent.
One of the significant advantages of this method is that it permits researchers to determine if changes in one variable cause shifts in each other.
While experiments in psychology typically have many moving parts (and can be relatively complex), an easy investigation is rather fundamental. Still, it does allow researchers to specify cause-and-effect associations between variables.
Most simple experiments use a control group, which involves those who do not receive the treatment, and an experimental group, which involves those who do receive the treatment.
An example of experimental research would be when a pharmaceutical company wants to test a new drug. They give one group a placebo (control group) and the other the actual pill (experimental group).
Descriptive Research
Descriptive research is generally used when it is challenging or even impossible to control the variables in question. Examples of descriptive analysis include naturalistic observation, case studies , and correlation studies .
One example of descriptive research includes phone surveys that marketers often use. While they typically do not allow researchers to identify cause and effect, correlational studies are quite common in psychology research. They make it possible to spot associations between distinct variables and measure the solidity of those relationships.
Step 5: Analyze the Data and Draw Conclusions
Once a researcher has designed and done the investigation and collected sufficient data, it is time to inspect this gathered information and judge what has been found. Researchers can summarize the data, interpret the results, and draw conclusions based on this evidence using analyses and statistics.
Upon completion of the experiment, you can collect your measurements and analyze the data using statistics. Based on the outcomes, you will either reject or confirm your hypothesis.
Analyze the Data
So, how does a researcher determine what the results of their study mean? Statistical analysis can either support or refute a researcher’s hypothesis and can also be used to determine if the conclusions are statistically significant.
When outcomes are said to be “statistically significant,” it is improbable that these results are due to luck or chance. Based on these observations, investigators must then determine what the results mean.
An experiment will support a hypothesis in some circumstances, but sometimes it fails to be truthful in other cases.
What occurs if the developments of a psychology investigation do not endorse the researcher’s hypothesis? It does mean that the study was worthless. Simply because the findings fail to defend the researcher’s hypothesis does not mean that the examination is not helpful or instructive.
This kind of research plays a vital role in supporting scientists in developing unexplored questions and hypotheses to investigate in the future. After decisions have been made, the next step is to communicate the results with the rest of the scientific community.
This is an integral part of the process because it contributes to the general knowledge base and can assist other scientists in finding new research routes to explore.
If the hypothesis is not supported, a researcher should acknowledge the experiment’s results, formulate a new hypothesis, and develop a new experiment.
We must avoid any reference to results proving a theory as this implies 100% certainty, and there is always a chance that evidence may exist that could refute a theory.
Draw Conclusions and Interpret the Data
When the empirical observations disagree with the hypothesis, a number of possibilities must be considered. It might be that the theory is incorrect, in which case it needs altering, so it fully explains the data.
Alternatively, it might be that the hypothesis was poorly derived from the original theory, in which case the scientists were expecting the wrong thing to happen.
It might also be that the research was poorly conducted, or used an inappropriate method, or there were factors in play that the researchers did not consider. This will begin the process of the scientific method again.
If the hypothesis is supported, the researcher can find more evidence to support their hypothesis or look for counter-evidence to strengthen their hypothesis further.
In either scenario, the researcher should share their results with the greater scientific community.
Step 6: Share Your Results
One of the final stages of the research cycle involves the publication of the research. Once the report is written, the researcher(s) may submit the work for publication in an appropriate journal.
Usually, this is done by writing up a study description and publishing the article in a professional or academic journal. The studies and conclusions of psychological work can be seen in peer-reviewed journals such as Developmental Psychology , Psychological Bulletin, the Journal of Social Psychology, and numerous others.
Scientists should report their findings by writing up a description of their study and any subsequent findings. This enables other researchers to build upon the present research or replicate the results.
As outlined by the American Psychological Association (APA), there is a typical structure of a journal article that follows a specified format. In these articles, researchers:
- Supply a brief narrative and background on previous research
- Give their hypothesis
- Specify who participated in the study and how they were chosen
- Provide operational definitions for each variable
- Explain the measures and methods used to collect data
- Describe how the data collected was interpreted
- Discuss what the outcomes mean
A detailed record of psychological studies and all scientific studies is vital to clearly explain the steps and procedures used throughout the study. So that other researchers can try this experiment too and replicate the results.
The editorial process utilized by academic and professional journals guarantees that each submitted article undergoes a thorough peer review to help assure that the study is scientifically sound. Once published, the investigation becomes another piece of the current puzzle of our knowledge “base” on that subject.
This last step is important because all results, whether they supported or did not support the hypothesis, can contribute to the scientific community. Publication of empirical observations leads to more ideas that are tested against the real world, and so on. In this sense, the scientific process is circular.
The editorial process utilized by academic and professional journals guarantees that each submitted article undergoes a thorough peer review to help assure that the study is scientifically sound.
Once published, the investigation becomes another piece of the current puzzle of our knowledge “base” on that subject.
By replicating studies, psychologists can reduce errors, validate theories, and gain a stronger understanding of a particular topic.
Step 7: Repeat the Scientific Method (Iteration)
Now, if one’s hypothesis turns out to be accurate, find more evidence or find counter-evidence. If one’s hypothesis is false, create a new hypothesis or try again.
One may wish to revise their first hypothesis to make a more niche experiment to design or a different specific question to test.
The amazingness of the scientific method is that it is a comprehensive and straightforward process that scientists, and everyone, can utilize over and over again.
So, draw conclusions and repeat because the scientific method is never-ending, and no result is ever considered perfect.
The scientific method is a process of:
- Making an observation.
- Forming a hypothesis.
- Making a prediction.
- Experimenting to test the hypothesis.
The procedure of repeating the scientific method is crucial to science and all fields of human knowledge.
Further Information
- Karl Popper – Falsification
- Thomas – Kuhn Paradigm Shift
- Positivism in Sociology: Definition, Theory & Examples
- Is Psychology a Science?
- Psychology as a Science (PDF)
List the 6 steps of the scientific methods in order
- Make an observation (theory construction)
- Ask a question. A scientific question must be defined, testable, and measurable.
- Form a hypothesis (make predictions)
- Run an experiment to test the hypothesis (gather data)
- Analyze the data and draw conclusions
- Share your results so that other researchers can make new hypotheses
What is the first step of the scientific method?
The first step of the scientific method is making an observation. This involves noticing and describing a phenomenon or group of phenomena that one finds interesting and wishes to explain.
Observations can occur in a natural setting or within the confines of a laboratory. The key point is that the observation provides the initial question or problem that the rest of the scientific method seeks to answer or solve.
What is the scientific method?
The scientific method is a step-by-step process that investigators can follow to determine if there is a causal connection between two or more variables.
Psychologists and other scientists regularly suggest motivations for human behavior. On a more casual level, people judge other people’s intentions, incentives, and actions daily.
While our standard assessments of human behavior are subjective and anecdotal, researchers use the scientific method to study psychology objectively and systematically.
All utilize a scientific method to study distinct aspects of people’s thinking and behavior. This process allows scientists to analyze and understand various psychological phenomena, but it also provides investigators and others a way to disseminate and debate the results of their studies.
The outcomes of these studies are often noted in popular media, which leads numerous to think about how or why researchers came to the findings they did.
Why Use the Six Steps of the Scientific Method
The goal of scientists is to understand better the world that surrounds us. Scientific research is the most critical tool for navigating and learning about our complex world.
Without it, we would be compelled to rely solely on intuition, other people’s power, and luck. We can eliminate our preconceived concepts and superstitions through methodical scientific research and gain an objective sense of ourselves and our world.
All psychological studies aim to explain, predict, and even control or impact mental behaviors or processes. So, psychologists use and repeat the scientific method (and its six steps) to perform and record essential psychological research.
So, psychologists focus on understanding behavior and the cognitive (mental) and physiological (body) processes underlying behavior.
In the real world, people use to understand the behavior of others, such as intuition and personal experience. The hallmark of scientific research is evidence to support a claim.
Scientific knowledge is empirical, meaning it is grounded in objective, tangible evidence that can be observed repeatedly, regardless of who is watching.
The scientific method is crucial because it minimizes the impact of bias or prejudice on the experimenter. Regardless of how hard one tries, even the best-intentioned scientists can’t escape discrimination. can’t
It stems from personal opinions and cultural beliefs, meaning any mortal filters data based on one’s experience. Sadly, this “filtering” process can cause a scientist to favor one outcome over another.
For an everyday person trying to solve a minor issue at home or work, succumbing to these biases is not such a big deal; in fact, most times, it is important.
But in the scientific community, where results must be inspected and reproduced, bias or discrimination must be avoided.
When to Use the Six Steps of the Scientific Method ?
One can use the scientific method anytime, anywhere! From the smallest conundrum to solving global problems, it is a process that can be applied to any science and any investigation.
Even if you are not considered a “scientist,” you will be surprised to know that people of all disciplines use it for all kinds of dilemmas.
Try to catch yourself next time you come by a question and see how you subconsciously or consciously use the scientific method.
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scientific method
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- University of Nevada, Reno - College of Agriculture, Biotechnology and Natural Resources Extension - The Scientific Method
- World History Encyclopedia - Scientific Method
- LiveScience - What Is Science?
- Verywell Mind - Scientific Method Steps in Psychology Research
- WebMD - What is the Scientific Method?
- Chemistry LibreTexts - The Scientific Method
- National Center for Biotechnology Information - PubMed Central - Redefining the scientific method: as the use of sophisticated scientific methods that extend our mind
- Khan Academy - The scientific method
- Simply Psychology - What are the steps in the Scientific Method?
- Stanford Encyclopedia of Philosophy - Scientific Method
scientific method , mathematical and experimental technique employed in the sciences . More specifically, it is the technique used in the construction and testing of a scientific hypothesis .
The process of observing, asking questions, and seeking answers through tests and experiments is not unique to any one field of science. In fact, the scientific method is applied broadly in science, across many different fields. Many empirical sciences, especially the social sciences , use mathematical tools borrowed from probability theory and statistics , together with outgrowths of these, such as decision theory , game theory , utility theory, and operations research . Philosophers of science have addressed general methodological problems, such as the nature of scientific explanation and the justification of induction .
The scientific method is critical to the development of scientific theories , which explain empirical (experiential) laws in a scientifically rational manner. In a typical application of the scientific method, a researcher develops a hypothesis , tests it through various means, and then modifies the hypothesis on the basis of the outcome of the tests and experiments. The modified hypothesis is then retested, further modified, and tested again, until it becomes consistent with observed phenomena and testing outcomes. In this way, hypotheses serve as tools by which scientists gather data. From that data and the many different scientific investigations undertaken to explore hypotheses, scientists are able to develop broad general explanations, or scientific theories.
See also Mill’s methods ; hypothetico-deductive method .
How to Write a Hypothesis in 6 Steps, With Examples
A hypothesis is a statement that explains the predictions and reasoning of your research—an “educated guess” about how your scientific experiments will end. As a fundamental part of the scientific method, a good hypothesis is carefully written, but even the simplest ones can be difficult to put into words.
Want to know how to write a hypothesis for your academic paper ? Below we explain the different types of hypotheses, what a good hypothesis requires, the steps to write your own, and plenty of examples.
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What is a hypothesis?
One of our 10 essential words for university success , a hypothesis is one of the earliest stages of the scientific method. It’s essentially an educated guess—based on observations—of what the results of your experiment or research will be.
Some hypothesis examples include:
- If I water plants daily they will grow faster.
- Adults can more accurately guess the temperature than children can.
- Butterflies prefer white flowers to orange ones.
If you’ve noticed that watering your plants every day makes them grow faster, your hypothesis might be “plants grow better with regular watering.” From there, you can begin experiments to test your hypothesis; in this example, you might set aside two plants, water one but not the other, and then record the results to see the differences.
The language of hypotheses always discusses variables , or the elements that you’re testing. Variables can be objects, events, concepts, etc.—whatever is observable.
There are two types of variables: independent and dependent. Independent variables are the ones that you change for your experiment, whereas dependent variables are the ones that you can only observe. In the above example, our independent variable is how often we water the plants and the dependent variable is how well they grow.
Hypotheses determine the direction and organization of your subsequent research methods, and that makes them a big part of writing a research paper . Ultimately the reader wants to know whether your hypothesis was proven true or false, so it must be written clearly in the introduction and/or abstract of your paper.
7 examples of hypotheses
Depending on the nature of your research and what you expect to find, your hypothesis will fall into one or more of the seven main categories. Keep in mind that these categories are not exclusive, so the same hypothesis might qualify as several different types.
1 Simple hypothesis
A simple hypothesis suggests only the relationship between two variables: one independent and one dependent.
- If you stay up late, then you feel tired the next day.
- Turning off your phone makes it charge faster.
2 Complex hypothesis
A complex hypothesis suggests the relationship between more than two variables, for example, two independents and one dependent, or vice versa.
- People who both (1) eat a lot of fatty foods and (2) have a family history of health problems are more likely to develop heart diseases.
- Older people who live in rural areas are happier than younger people who live in rural areas.
3 Null hypothesis
A null hypothesis, abbreviated as H 0 , suggests that there is no relationship between variables.
- There is no difference in plant growth when using either bottled water or tap water.
- Professional psychics do not win the lottery more than other people.
4 Alternative hypothesis
An alternative hypothesis, abbreviated as H 1 or H A , is used in conjunction with a null hypothesis. It states the opposite of the null hypothesis, so that one and only one must be true.
- Plants grow better with bottled water than tap water.
- Professional psychics win the lottery more than other people.
5 Logical hypothesis
A logical hypothesis suggests a relationship between variables without actual evidence. Claims are instead based on reasoning or deduction, but lack actual data.
- An alien raised on Venus would have trouble breathing in Earth’s atmosphere.
- Dinosaurs with sharp, pointed teeth were probably carnivores.
6 Empirical hypothesis
An empirical hypothesis, also known as a “working hypothesis,” is one that is currently being tested. Unlike logical hypotheses, empirical hypotheses rely on concrete data.
- Customers at restaurants will tip the same even if the wait staff’s base salary is raised.
- Washing your hands every hour can reduce the frequency of illness.
7 Statistical hypothesis
A statistical hypothesis is when you test only a sample of a population and then apply statistical evidence to the results to draw a conclusion about the entire population. Instead of testing everything , you test only a portion and generalize the rest based on preexisting data.
- In humans, the birth-gender ratio of males to females is 1.05 to 1.00.
- Approximately 2% of the world population has natural red hair.
What makes a good hypothesis?
No matter what you’re testing, a good hypothesis is written according to the same guidelines. In particular, keep these five characteristics in mind:
Cause and effect
Hypotheses always include a cause-and-effect relationship where one variable causes another to change (or not change if you’re using a null hypothesis). This can best be reflected as an if-then statement: If one variable occurs, then another variable changes.
Testable prediction
Most hypotheses are designed to be tested (with the exception of logical hypotheses). Before committing to a hypothesis, make sure you’re actually able to conduct experiments on it. Choose a testable hypothesis with an independent variable that you have absolute control over.
Independent and dependent variables
Define your variables in your hypothesis so your readers understand the big picture. You don’t have to specifically say which ones are independent and dependent variables, but you definitely want to mention them all.
Candid language
Writing can easily get convoluted, so make sure your hypothesis remains as simple and clear as possible. Readers use your hypothesis as a contextual pillar to unify your entire paper, so there should be no confusion or ambiguity. If you’re unsure about your phrasing, try reading your hypothesis to a friend to see if they understand.
Adherence to ethics
It’s not always about what you can test, but what you should test. Avoid hypotheses that require questionable or taboo experiments to keep ethics (and therefore, credibility) intact.
How to write a hypothesis in 6 steps
1 ask a question.
Curiosity has inspired some of history’s greatest scientific achievements, so a good place to start is to ask yourself questions about the world around you. Why are things the way they are? What causes the factors you see around you? If you can, choose a research topic that you’re interested in so your curiosity comes naturally.
2 Conduct preliminary research
Next, collect some background information on your topic. How much background information you need depends on what you’re attempting. It could require reading several books, or it could be as simple as performing a web search for a quick answer. You don’t necessarily have to prove or disprove your hypothesis at this stage; rather, collect only what you need to prove or disprove it yourself.
3 Define your variables
Once you have an idea of what your hypothesis will be, select which variables are independent and which are dependent. Remember that independent variables can only be factors that you have absolute control over, so consider the limits of your experiment before finalizing your hypothesis.
4 Phrase it as an if-then statement
When writing a hypothesis, it helps to phrase it using an if-then format, such as, “ If I water a plant every day, then it will grow better.” This format can get tricky when dealing with multiple variables, but in general, it’s a reliable method for expressing the cause-and-effect relationship you’re testing.
5 Collect data to support your hypothesis
A hypothesis is merely a means to an end. The priority of any scientific research is the conclusion. Once you have your hypothesis laid out and your variables chosen, you can then begin your experiments. Ideally, you’ll collect data to support your hypothesis, but don’t worry if your research ends up proving it wrong—that’s all part of the scientific method.
6 Write with confidence
Last, you’ll want to record your findings in a research paper for others to see. This requires a bit of writing know-how, quite a different skill set than conducting experiments.
That’s where Grammarly can be a major help; our writing suggestions point out not only grammar and spelling mistakes , but also new word choices and better phrasing. While you write, Grammarly automatically recommends optimal language and highlights areas where readers might get confused, ensuring that your hypothesis—and your final paper—are clear and polished.
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- How to Write a Strong Hypothesis | Steps & Examples
How to Write a Strong Hypothesis | Steps & Examples
Published on May 6, 2022 by Shona McCombes . Revised on November 20, 2023.
A hypothesis is a statement that can be tested by scientific research. If you want to test a relationship between two or more variables, you need to write hypotheses before you start your experiment or data collection .
Example: Hypothesis
Daily apple consumption leads to fewer doctor’s visits.
Table of contents
What is a hypothesis, developing a hypothesis (with example), hypothesis examples, other interesting articles, frequently asked questions about writing hypotheses.
A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question.
A hypothesis is not just a guess – it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations and statistical analysis of data).
Variables in hypotheses
Hypotheses propose a relationship between two or more types of variables .
- An independent variable is something the researcher changes or controls.
- A dependent variable is something the researcher observes and measures.
If there are any control variables , extraneous variables , or confounding variables , be sure to jot those down as you go to minimize the chances that research bias will affect your results.
In this example, the independent variable is exposure to the sun – the assumed cause . The dependent variable is the level of happiness – the assumed effect .
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Step 1. Ask a question
Writing a hypothesis begins with a research question that you want to answer. The question should be focused, specific, and researchable within the constraints of your project.
Step 2. Do some preliminary research
Your initial answer to the question should be based on what is already known about the topic. Look for theories and previous studies to help you form educated assumptions about what your research will find.
At this stage, you might construct a conceptual framework to ensure that you’re embarking on a relevant topic . This can also help you identify which variables you will study and what you think the relationships are between them. Sometimes, you’ll have to operationalize more complex constructs.
Step 3. Formulate your hypothesis
Now you should have some idea of what you expect to find. Write your initial answer to the question in a clear, concise sentence.
4. Refine your hypothesis
You need to make sure your hypothesis is specific and testable. There are various ways of phrasing a hypothesis, but all the terms you use should have clear definitions, and the hypothesis should contain:
- The relevant variables
- The specific group being studied
- The predicted outcome of the experiment or analysis
5. Phrase your hypothesis in three ways
To identify the variables, you can write a simple prediction in if…then form. The first part of the sentence states the independent variable and the second part states the dependent variable.
In academic research, hypotheses are more commonly phrased in terms of correlations or effects, where you directly state the predicted relationship between variables.
If you are comparing two groups, the hypothesis can state what difference you expect to find between them.
6. Write a null hypothesis
If your research involves statistical hypothesis testing , you will also have to write a null hypothesis . The null hypothesis is the default position that there is no association between the variables. The null hypothesis is written as H 0 , while the alternative hypothesis is H 1 or H a .
- H 0 : The number of lectures attended by first-year students has no effect on their final exam scores.
- H 1 : The number of lectures attended by first-year students has a positive effect on their final exam scores.
Research question | Hypothesis | Null hypothesis |
---|---|---|
What are the health benefits of eating an apple a day? | Increasing apple consumption in over-60s will result in decreasing frequency of doctor’s visits. | Increasing apple consumption in over-60s will have no effect on frequency of doctor’s visits. |
Which airlines have the most delays? | Low-cost airlines are more likely to have delays than premium airlines. | Low-cost and premium airlines are equally likely to have delays. |
Can flexible work arrangements improve job satisfaction? | Employees who have flexible working hours will report greater job satisfaction than employees who work fixed hours. | There is no relationship between working hour flexibility and job satisfaction. |
How effective is high school sex education at reducing teen pregnancies? | Teenagers who received sex education lessons throughout high school will have lower rates of unplanned pregnancy teenagers who did not receive any sex education. | High school sex education has no effect on teen pregnancy rates. |
What effect does daily use of social media have on the attention span of under-16s? | There is a negative between time spent on social media and attention span in under-16s. | There is no relationship between social media use and attention span in under-16s. |
If you want to know more about the research process , methodology , research bias , or statistics , make sure to check out some of our other articles with explanations and examples.
- Sampling methods
- Simple random sampling
- Stratified sampling
- Cluster sampling
- Likert scales
- Reproducibility
Statistics
- Null hypothesis
- Statistical power
- Probability distribution
- Effect size
- Poisson distribution
Research bias
- Optimism bias
- Cognitive bias
- Implicit bias
- Hawthorne effect
- Anchoring bias
- Explicit bias
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A hypothesis is not just a guess — it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations and statistical analysis of data).
Null and alternative hypotheses are used in statistical hypothesis testing . The null hypothesis of a test always predicts no effect or no relationship between variables, while the alternative hypothesis states your research prediction of an effect or relationship.
Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is used by scientists to test specific predictions, called hypotheses , by calculating how likely it is that a pattern or relationship between variables could have arisen by chance.
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Scientific Method Steps in Psychology Research
Steps, Uses, and Key Terms
Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."
Emily is a board-certified science editor who has worked with top digital publishing brands like Voices for Biodiversity, Study.com, GoodTherapy, Vox, and Verywell.
Verywell / Theresa Chiechi
How do researchers investigate psychological phenomena? They utilize a process known as the scientific method to study different aspects of how people think and behave.
When conducting research, the scientific method steps to follow are:
- Observe what you want to investigate
- Ask a research question and make predictions
- Test the hypothesis and collect data
- Examine the results and draw conclusions
- Report and share the results
This process not only allows scientists to investigate and understand different psychological phenomena but also provides researchers and others a way to share and discuss the results of their studies.
Generally, there are five main steps in the scientific method, although some may break down this process into six or seven steps. An additional step in the process can also include developing new research questions based on your findings.
What Is the Scientific Method?
What is the scientific method and how is it used in psychology?
The scientific method consists of five steps. It is essentially a step-by-step process that researchers can follow to determine if there is some type of relationship between two or more variables.
By knowing the steps of the scientific method, you can better understand the process researchers go through to arrive at conclusions about human behavior.
Scientific Method Steps
While research studies can vary, these are the basic steps that psychologists and scientists use when investigating human behavior.
The following are the scientific method steps:
Step 1. Make an Observation
Before a researcher can begin, they must choose a topic to study. Once an area of interest has been chosen, the researchers must then conduct a thorough review of the existing literature on the subject. This review will provide valuable information about what has already been learned about the topic and what questions remain to be answered.
A literature review might involve looking at a considerable amount of written material from both books and academic journals dating back decades.
The relevant information collected by the researcher will be presented in the introduction section of the final published study results. This background material will also help the researcher with the first major step in conducting a psychology study: formulating a hypothesis.
Step 2. Ask a Question
Once a researcher has observed something and gained some background information on the topic, the next step is to ask a question. The researcher will form a hypothesis, which is an educated guess about the relationship between two or more variables
For example, a researcher might ask a question about the relationship between sleep and academic performance: Do students who get more sleep perform better on tests at school?
In order to formulate a good hypothesis, it is important to think about different questions you might have about a particular topic.
You should also consider how you could investigate the causes. Falsifiability is an important part of any valid hypothesis. In other words, if a hypothesis was false, there needs to be a way for scientists to demonstrate that it is false.
Step 3. Test Your Hypothesis and Collect Data
Once you have a solid hypothesis, the next step of the scientific method is to put this hunch to the test by collecting data. The exact methods used to investigate a hypothesis depend on exactly what is being studied. There are two basic forms of research that a psychologist might utilize: descriptive research or experimental research.
Descriptive research is typically used when it would be difficult or even impossible to manipulate the variables in question. Examples of descriptive research include case studies, naturalistic observation , and correlation studies. Phone surveys that are often used by marketers are one example of descriptive research.
Correlational studies are quite common in psychology research. While they do not allow researchers to determine cause-and-effect, they do make it possible to spot relationships between different variables and to measure the strength of those relationships.
Experimental research is used to explore cause-and-effect relationships between two or more variables. This type of research involves systematically manipulating an independent variable and then measuring the effect that it has on a defined dependent variable .
One of the major advantages of this method is that it allows researchers to actually determine if changes in one variable actually cause changes in another.
While psychology experiments are often quite complex, a simple experiment is fairly basic but does allow researchers to determine cause-and-effect relationships between variables. Most simple experiments use a control group (those who do not receive the treatment) and an experimental group (those who do receive the treatment).
Step 4. Examine the Results and Draw Conclusions
Once a researcher has designed the study and collected the data, it is time to examine this information and draw conclusions about what has been found. Using statistics , researchers can summarize the data, analyze the results, and draw conclusions based on this evidence.
So how does a researcher decide what the results of a study mean? Not only can statistical analysis support (or refute) the researcher’s hypothesis; it can also be used to determine if the findings are statistically significant.
When results are said to be statistically significant, it means that it is unlikely that these results are due to chance.
Based on these observations, researchers must then determine what the results mean. In some cases, an experiment will support a hypothesis, but in other cases, it will fail to support the hypothesis.
So what happens if the results of a psychology experiment do not support the researcher's hypothesis? Does this mean that the study was worthless?
Just because the findings fail to support the hypothesis does not mean that the research is not useful or informative. In fact, such research plays an important role in helping scientists develop new questions and hypotheses to explore in the future.
After conclusions have been drawn, the next step is to share the results with the rest of the scientific community. This is an important part of the process because it contributes to the overall knowledge base and can help other scientists find new research avenues to explore.
Step 5. Report the Results
The final step in a psychology study is to report the findings. This is often done by writing up a description of the study and publishing the article in an academic or professional journal. The results of psychological studies can be seen in peer-reviewed journals such as Psychological Bulletin , the Journal of Social Psychology , Developmental Psychology , and many others.
The structure of a journal article follows a specified format that has been outlined by the American Psychological Association (APA) . In these articles, researchers:
- Provide a brief history and background on previous research
- Present their hypothesis
- Identify who participated in the study and how they were selected
- Provide operational definitions for each variable
- Describe the measures and procedures that were used to collect data
- Explain how the information collected was analyzed
- Discuss what the results mean
Why is such a detailed record of a psychological study so important? By clearly explaining the steps and procedures used throughout the study, other researchers can then replicate the results. The editorial process employed by academic and professional journals ensures that each article that is submitted undergoes a thorough peer review, which helps ensure that the study is scientifically sound.
Once published, the study becomes another piece of the existing puzzle of our knowledge base on that topic.
Before you begin exploring the scientific method steps, here's a review of some key terms and definitions that you should be familiar with:
- Falsifiable : The variables can be measured so that if a hypothesis is false, it can be proven false
- Hypothesis : An educated guess about the possible relationship between two or more variables
- Variable : A factor or element that can change in observable and measurable ways
- Operational definition : A full description of exactly how variables are defined, how they will be manipulated, and how they will be measured
Uses for the Scientific Method
The goals of psychological studies are to describe, explain, predict and perhaps influence mental processes or behaviors. In order to do this, psychologists utilize the scientific method to conduct psychological research. The scientific method is a set of principles and procedures that are used by researchers to develop questions, collect data, and reach conclusions.
Goals of Scientific Research in Psychology
Researchers seek not only to describe behaviors and explain why these behaviors occur; they also strive to create research that can be used to predict and even change human behavior.
Psychologists and other social scientists regularly propose explanations for human behavior. On a more informal level, people make judgments about the intentions, motivations , and actions of others on a daily basis.
While the everyday judgments we make about human behavior are subjective and anecdotal, researchers use the scientific method to study psychology in an objective and systematic way. The results of these studies are often reported in popular media, which leads many to wonder just how or why researchers arrived at the conclusions they did.
Examples of the Scientific Method
Now that you're familiar with the scientific method steps, it's useful to see how each step could work with a real-life example.
Say, for instance, that researchers set out to discover what the relationship is between psychotherapy and anxiety .
- Step 1. Make an observation : The researchers choose to focus their study on adults ages 25 to 40 with generalized anxiety disorder.
- Step 2. Ask a question : The question they want to answer in their study is: Do weekly psychotherapy sessions reduce symptoms in adults ages 25 to 40 with generalized anxiety disorder?
- Step 3. Test your hypothesis : Researchers collect data on participants' anxiety symptoms . They work with therapists to create a consistent program that all participants undergo. Group 1 may attend therapy once per week, whereas group 2 does not attend therapy.
- Step 4. Examine the results : Participants record their symptoms and any changes over a period of three months. After this period, people in group 1 report significant improvements in their anxiety symptoms, whereas those in group 2 report no significant changes.
- Step 5. Report the results : Researchers write a report that includes their hypothesis, information on participants, variables, procedure, and conclusions drawn from the study. In this case, they say that "Weekly therapy sessions are shown to reduce anxiety symptoms in adults ages 25 to 40."
Of course, there are many details that go into planning and executing a study such as this. But this general outline gives you an idea of how an idea is formulated and tested, and how researchers arrive at results using the scientific method.
Erol A. How to conduct scientific research ? Noro Psikiyatr Ars . 2017;54(2):97-98. doi:10.5152/npa.2017.0120102
University of Minnesota. Psychologists use the scientific method to guide their research .
Shaughnessy, JJ, Zechmeister, EB, & Zechmeister, JS. Research Methods In Psychology . New York: McGraw Hill Education; 2015.
By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."
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Scientific Method
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The scientific method is the process by which scientists of all fields attempt to explain the phenomena in the world. It is how science is conducted--through experimentation. Generally, the scientific method refers to a set of steps whereby a scientist can form a conjecture (the hypothesis) for why something functions the way it does and then test their hypothesis. It is an empirical process; it uses real world data to prove the hypothesis. There is no exact set of \(x\) number of steps to conduct scientific experiments, or even some exact \(y\) number of experiments, but the general process involves making an observation, forming an hypothesis, forming a prediction from that hypothesis, and then experimental testing. The scientific method isn't limited to the physical or biological sciences, but also the social sciences, mathematics, computing and other fields where experimentation can be used to prove beliefs.
We could observe that whenever a fire is smothered, it goes out. For instance a small fire that is covered with a blanket is extinguished. We could hypothesize that the reason for this is that fire requires some gas in our air to form and remain a flame. We could then use a vacuum chamber to test this theory. We would predict that outside of a vacuum, a fire could be lit but inside of a vacuum, with no air, that the fire would not ignite. If we were to test this theory, perhaps in multiple vacuums with multiple forms of tinder/fuel (wood, paper, petrol, etc.) and multiple means of ignition, we would notice that the fire never ignites. If we wished, we could further refine our hypothesis, suggesting that fire can only ignite if there is sufficient oxygen in the air. This we'd also test in the vacuum chamber, by pulling out all the air, then adding in different gases. We would notice that the fire would only ignite in the presence of oxygen or an oxidizing agent . It is possible that other, incorrect hypothesis could have been initially formed--such as smothering decreases the surface area the fire has, and could try making different sized fires--and been proven incorrect. Also, it is important to note that this single set of experiments is not enough to turn this hypothesis into a theorem. More experimentation and discovery would be necessary.
The scientific method also refers to the fact that science is ongoing . In some cases scientists continue to collect data to prove and disprove old theories. Or in other cases, scientists have hypothesis for why the universe behaves the way it does but are unable to gather sufficient data to prove their hypothesis. For instance, until recent discoveries at LIGO scientists could not confirm what happened when two black holes collided, although they believed (and it was confirmed in February 2016) that colliding black holes produced gravitational waves .
Steps of the Scientific Method
Falsifiability and why "theory" doesn't mean "untrue", avoiding bias, history and philosophy of science.
The scientific method is often presented as a set of steps, but not always with the same number or type of steps. However, philosophers of science generally agree that any presentation of the scientific method should have the following four steps:
- Observe - Sometimes referred to as characterizing, defining, or measuring, experimenters first witness some aspect of the universe, for instance, an apple falling. These observations then form a question, such as "Why do objects fall to the earth?"
- Hypothesize - Scientists then come up with a theory as to why this happens, for instance, the mass of the earth attracts the apple from the air to the ground.
- Predict - Using the hypothesis, a scientist calculates what measurable data points they believe will result in a given experiment, for instance an apple at a height of \(9.8\) meters should fall to the ground in \(\sqrt{2}\) seconds, or should be at a velocity of \(9.8\sqrt{2}\) m/s the moment before it hits the ground.
- Experiment - A test is run to determine if the prediction was correct.
With the notion that repeating these steps is also important. If a prediction is proven to be incorrect then alternative predictions and tests are conducted. Maybe even a new hypothesis could be formulated. Even if the hypothesis and prediction are correct, additional predictions and tests need to be run to best support any theory.
While this process can be explained or categorized differently than this, all formulations of the scientific method have empirical observations, a testable hypothesis, and testing data to prove or disprove that hypothesis. Crucial to this, is that an experimenter searches for experiments that produce the most unlikely results and experiments that are least likely to be coincidental . Hypotheses that produce highly unlikely predictions, in situations where little else could explain the result, are more likely to be true. Bayes' theorem can be used to show which predictions are more or less unlikely given some evidence, i.e. which proven predictions are "stronger" than others. For instance, the theory of evolution has been supported by the consistency of DNA across species whose phenomenology are significantly different. Despite the diversity of plant and animal species on Earth, the majority of our DNA is the same, and only 20 amino acids are the building blocks for every known living organism. It would be highly unlikely that vastly different forms of life have the same building blocks after millions, if not billions, of years of external manipulation, if not for some common origin.
The word "theory" can lead to confusion about how true some scientific principle is. Under the scientific method scientists use the word "theory" even for key principles (like gravity) that have been rigorously proven by modern science. This is because the scientific community believes it is important that hypothesis be falsifiable . Falsifiability refers to the fact that theories have been tested in experiments where they could have failed but did not. So when scientists refer to a principle as a theory, for instance Einstein's theory of relativity , they're actually referring to a hypothesis that has undergone the scientific method, i.e. that has been tested and proven true.
For instance, scientists sometimes refer to evolution as the "theory of evolution," which has contributed to the erroneous belief that the modern scientific theory of evolution is false. Really what the "theory of evolution" refers to is the ample research, testing, and empirical evidence that all consistently prove evolution to be true.
That isn't to say that theories can't be later disproven. Part of the advantage to the scientific method is that no theory is ever considered an unbreakable rule. Some theories seem correct given experiments that are run at the time they're created, but are proven wrong as new methods of experimentation are conducted. For instance, Einstein himself believed that the universe was static, not growing or contracting. That was later proven to be false and replaced with a theory that the universe was expanding (the Friedmann-LeMaitre model of an expanding universe , which Einstein himself accepted), but that its rate of expansion was slowing down. This was, in turn, also proven incorrect. The rate of the universe's expansion is speeding up. [1] Generally though, theories are modified over time, they are shown to be true under certain conditions, or partly true, and the strength of a theory may also be related to how long it has held up, without modification, to scrutiny.
Peer review: In modern science, experimenters present both their findings and their methodology for review by their peers, other talented scientists and experimenters. This is done before a work is published, but also publication itself is considered a way of inviting peer review. By sharing and disseminating work widely, the greatest number of others can review the work and offer criticism as needed.
Reproducibility: Related to peer review, is the notion that the results from experiments should be possible to reproduce. If one scientist conducts some experiment, others should be able to conduct the same experiment on their own and achieve the same results. Reproducible experiments strengthen theories.
Double-Blind Testing: Primarily used in medical , psychological , and behavioral economic testing, double-blind testing refers to having a test and control group, and running the experiment such that the person conducting the experiment does not know which is which. For instance, in testing the efficacy of a new drug, a pharmaceutical company may have a medical practitioner administer the new drug to one third of the test population, an existing known drug to another third, and a placebo, meaning something that isn't a drug but seems like it, to the remaining third of the test population, but without the nurse knowing which drug is which. The practitioner would then, still blind, track the progress of the entire testing population, gathering data about each test subject.
Double-blind studies are done to avoid biases that manipulate data, like controlling for the placebo effect where just giving a patient a drug that they perceive will be a cure can be causally linked to a decrease in symptoms. This positive causal effect occurs even with the drug that shouldn't affect the patient in anyway, when it is a sugar pill, or water, so long as the patient believes they are receiving a cure. Also double-blind studies help prevent observation bias, where the administrator of the drug may expect the population who received the new drug to outperform others, and so many inadvertently rate their progress better than other test groups.
A pharmaceutical company has a new drug they want to test to determine its efficacy. They have a hypothesis that this drug is super effective at curing a disease. Which of the following experiments/results best reflects the principles of the scientific method? Which is most scientific?
A) They gave 100 patients with the disease the drug and 100 patients a placebo from a population of 100,000 with the disease, they strictly controlled these patient's diet, limited other medication, and 77 of the subjects reported that their happiness improved significantly.
B) They found a remote island with an indigenous population that's genetically different from other populations and where 200 patients have the disease. They gave 100 patients on the island the drug and 100 a placebo. They strictly controlled these patient's diet, limited other medication, and found that 84 of the test patients had higher red and white blood cell count than the control group, and lower incidents of mortality from the disease than non-island populations.
C) They gave 100 patients with the disease the drug and 100 patients a placebo from a population of 100,000 with the disease, they strictly controlled these patient's diet, limited other medication, and found that only 5 of the test patients had higher red and white blood cell count than the control group, with no other changes in health.
D) They gave 100 patients with the disease the drug and 100 patients a placebo from a population of 100,000 with the disease, allowed both patients to consume and medicate in whatever way those patients desired, and found that 68 of the test patients had higher red and white blood cell count than the control group, with faster speed-to-recovery.
The theory of the scientific method has evolved over time, with modern historians pointing to Aristotle as an originator, and many looking to Thomas Kuhn's seminal work "The Structure of Scientific Revolutions" as a key influence on current conceptions of the method.
Aristotle classified reasoning into three types:
- Abductive - Also known as guessing, abductive reasoning supposes that the most likely inference is correct. While this isn't rigorous, a well-informed individual is likely to make good guesses, and many significant theories of science have developed first from a guess.
- Deductive - Deductive reasoning uses premises to reach conclusions. One of the most famous examples being "All men are mortal. Socrates is a man. Therefore, Socrates is mortal."
- Inductive - Inductive reasoning is the one preferred by scientists, and can be considered an early version of the scientific method. Namely, inductive reasoning uses empirical observations to make inferences, and accounts for probability in those inferences. A theory reached by induction is said to be more or less likely to be true, stronger or weaker.
The philosophy of science refers to the logic and thinking behind the scientific method. It questions what makes something scientifically valid. For instance, the scientific method assumes that reality is objective, and that explanations exist for all phenomena humans can observe.
Thomas Kuhn's book is foundational to the philosophy of science and the way sociologists and historians look at science through the ages. In it, he popularized the term "paradigm shift" and promoted a historical understanding of scientific discovery not as a linear accumulation of understanding, but as a set of scientific revolutions that "shift" humanity's understanding. Further, paradigm shifts open up whole fields (for instance quantum mechanics , behavioral economics or genetics ) with new approaches to understand the universe. Also what scientists consider true is not purely objective, but based on the consensus of the scientific community.
- Nobelprize.org, . The Nobel Prize in Physics 2011 Saul Perlmutter, Brian P. Schmidt, Adam G. Riess . Retrieved October 24th 2016, from http://www.nobelprize.org/nobel_prizes/physics/laureates/2011/
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What Is the Scientific Method?
The scientific method is a systematic way of conducting experiments or studies so that you can explore the things you observe in the world and answer questions about them. The scientific method, also known as the hypothetico-deductive method, is a series of steps that can help you accurately describe the things you observe or improve your understanding of them.
Ultimately, your goal when you use the scientific method is to:
- Find a cause-and-effect relationship by asking a question about something you observed
- Collect as much evidence as you can about what you observed, as this can help you explore the connection between your evidence and what you observed
- Determine if all your evidence can be combined to answer your question in a way that makes sense
Francis Bacon and René Descartes are usually credited with formalizing the process in the 16th and 17th centuries. The two philosophers argued that research shouldn’t be guided by preset metaphysical ideas of how reality works. They supported the use of inductive reasoning to come up with hypotheses and understand new things about reality.
Scientific Method Steps
The scientific method is a step-by-step problem-solving process. These steps include:
Observe the world around you. This will help you come up with a topic you are interested in and want to learn more about. In many cases, you already have a topic in mind because you have a related question for which you couldn't find an immediate answer.
Either way, you'll start the process by finding out what people before you already know about the topic, as well as any questions that people are still asking about. You may need to look up and read books and articles from academic journals or talk to other people so that you understand as much as you possibly can about your topic. This will help you with your next step.
Ask questions. Asking questions about what you observed and learned from reading and talking to others can help you figure out what the "problem" is. Scientists try to ask questions that are both interesting and specific and can be answered with the help of a fairly easy experiment or series of experiments. Your question should have one part (called a variable) that you can change in your experiment and another variable that you can measure. Your goal is to design an experiment that is a "fair test," which is when all the conditions in the experiment are kept the same except for the one you change (called the experimental or independent variable).
Form a hypothesis and make predictions based on it. A hypothesis is an educated guess about the relationship between two or more variables in your question. A good hypothesis lets you predict what will happen when you test it in an experiment. Another important feature of a good hypothesis is that, if the hypothesis is wrong, you should be able to show that it's wrong. This is called falsifiability. If your experiment shows that your prediction is true, then your hypothesis is supported by your data.
Test your prediction by doing an experiment or making more observations. The way you test your prediction depends on what you are studying. The best support comes from an experiment, but in some cases, it's too hard or impossible to change the variables in an experiment. Sometimes, you may need to do descriptive research where you gather more observations instead of doing an experiment. You will carefully gather notes and measurements during your experiments or studies, and you can share them with other people interested in the same question as you. Ideally, you will also repeat your experiment a couple more times because it's possible to get a result by chance, but it's less possible to get the same result more than once by chance.
Draw a conclusion. You will analyze what you already know about your topic from your literature research and the data gathered during your experiment. This will help you decide if the conclusion you draw from your data supports or contradicts your hypothesis. If your results contradict your hypothesis, you can use this observation to form a new hypothesis and make a new prediction. This is why scientific research is ongoing and scientific knowledge is changing all the time. It's very common for scientists to get results that don't support their hypotheses. In fact, you sometimes learn more about the world when your experiments don't support your hypotheses because it leads you to ask more questions. And this time around, you already know that one possible explanation is likely wrong.
Use your results to guide your next steps (iterate). For instance, if your hypothesis is supported, you may do more experiments to confirm it. Or you could come up with a hypothesis about why it works this way and design an experiment to test that. If your hypothesis is not supported, you can come up with another hypothesis and do experiments to test it. You'll rarely get the right hypothesis in one go. Most of the time, you'll have to go back to the hypothesis stage and try again. Every attempt offers you important information that helps you improve your next round of questions, hypotheses, and predictions.
Share your results. Scientific research isn't something you can do on your own; you must work with other people to do it. You may be able to do an experiment or a series of experiments on your own, but you can't come up with all the ideas or do all the experiments by yourself .
Scientists and researchers usually share information by publishing it in a scientific journal or by presenting it to their colleagues during meetings and scientific conferences. These journals are read and the conferences are attended by other researchers who are interested in the same questions. If there's anything wrong with your hypothesis, prediction, experiment design, or conclusion, other researchers will likely find it and point it out to you.
It can be scary, but it's a critical part of doing scientific research. You must let your research be examined by other researchers who are as interested and knowledgeable about your question as you. This process helps other researchers by pointing out hypotheses that have been proved wrong and why they are wrong. It helps you by identifying flaws in your thinking or experiment design. And if you don't share what you've learned and let other people ask questions about it, it's not helpful to your or anyone else's understanding of what happens in the world.
Scientific Method Example
Here's an everyday example of how you can apply the scientific method to understand more about your world so you can solve your problems in a helpful way.
Let's say you put slices of bread in your toaster and press the button, but nothing happens. Your toaster isn't working, but you can't afford to buy a new one right now. You might be able to rescue it from the trash can if you can figure out what's wrong with it. So, let's figure out what's wrong with your toaster.
Observation. Your toaster isn't working to toast your bread.
Ask a question. In this case, you're asking, "Why isn't my toaster working?" You could even do a bit of preliminary research by looking in the owner's manual for your toaster. The manufacturer has likely tested your toaster model under many conditions, and they may have some ideas for where to start with your hypothesis.
Form a hypothesis and make predictions based on it. Your hypothesis should be a potential explanation or answer to the question that you can test to see if it's correct. One possible explanation that we could test is that the power outlet is broken. Our prediction is that if the outlet is broken, then plugging it into a different outlet should make the toaster work again.
Test your prediction by doing an experiment or making more observations. You plug the toaster into a different outlet and try to toast your bread.
If that works, then your hypothesis is supported by your experimental data. Results that support your hypothesis don't prove it right; they simply suggest that it's a likely explanation. This uncertainty arises because, in the real world, we can't rule out the possibility of mistakes, wrong assumptions, or weird coincidences affecting the results. If the toaster doesn’t work even after plugging it into a different outlet, then your hypothesis is not supported and it's likely the wrong explanation.
Use your results to guide your next steps (iteration). If your toaster worked, you may decide to do further tests to confirm it or revise it. For example, you could plug something else that you know is working into the first outlet to see if that stops working too. That would be further confirmation that your hypothesis is correct.
If your toaster failed to toast when plugged into the second outlet, you need a new hypothesis. For example, your next hypothesis might be that the toaster has a shorted wire. You could test this hypothesis directly if you have the right equipment and training, or you could take it to a repair shop where they could test that hypothesis for you.
Share your results. For this everyday example, you probably wouldn't want to write a paper, but you could share your problem-solving efforts with your housemates or anyone you hire to repair your outlet or help you test if the toaster has a short circuit.
What the Scientific Method Is Used For
The scientific method is useful whenever you need to reason logically about your questions and gather evidence to support your problem-solving efforts. So, you can use it in everyday life to answer many of your questions; however, when most people think of the scientific method, they likely think of using it to:
Describe how nature works . It can be hard to accurately describe how nature works because it's almost impossible to account for every variable that's involved in a natural process. Researchers may not even know about many of the variables that are involved. In some cases, all you can do is make assumptions. But you can use the scientific method to logically disprove wrong assumptions by identifying flaws in the reasoning.
Do scientific research in a laboratory to develop things such as new medicines.
Develop critical thinking skills. Using the scientific method may help you develop critical thinking in your daily life because you learn to systematically ask questions and gather evidence to find answers. Without logical reasoning, you might be more likely to have a distorted perspective or bias. Bias is the inclination we all have to favor one perspective (usually our own) over another.
The scientific method doesn't perfectly solve the problem of bias, but it does make it harder for an entire field to be biased in the same direction. That's because it's unlikely that all the people working in a field have the same biases. It also helps make the biases of individuals more obvious because if you repeatedly misinterpret information in the same way in multiple experiments or over a period, the other people working on the same question will notice. If you don't correct your bias when others point it out to you, you'll lose your credibility. Other people might then stop believing what you have to say.
Why Is the Scientific Method Important?
When you use the scientific method, your goal is to do research in a fair, unbiased, and repeatable way. The scientific method helps meet these goals because:
It's a systematic approach to problem-solving. It can help you figure out where you're going wrong in your thinking and research if you're not getting helpful answers to your questions. Helpful answers solve problems and keep you moving forward. So, a systematic approach helps you improve your problem-solving abilities if you get stuck.
It can help you solve your problems. The scientific method helps you isolate problems by focusing on what's important. In addition, it can help you make your solutions better every time you go through the process.
It helps you eliminate (or become aware of) your personal biases. It can help you limit the influence of your own personal, preconceived notions . A big part of the process is considering what other people already know and think about your question. It also involves sharing what you've learned and letting other people ask about your methods and conclusions. At the end of the process, even if you still think your answer is best, you have considered what other people know and think about the question.
The scientific method is a systematic way of conducting experiments or studies so that you can explore the world around you and answer questions using reason and evidence. It's a step-by-step problem-solving process that involves: (1) observation, (2) asking questions, (3) forming hypotheses and making predictions, (4) testing your hypotheses through experiments or more observations, (5) using what you learned through experiment or observation to guide further investigation, and (6) sharing your results.
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Science and the scientific method: Definitions and examples
Here's a look at the foundation of doing science — the scientific method.
The scientific method
Hypothesis, theory and law, a brief history of science, additional resources, bibliography.
Science is a systematic and logical approach to discovering how things in the universe work. It is also the body of knowledge accumulated through the discoveries about all the things in the universe.
The word "science" is derived from the Latin word "scientia," which means knowledge based on demonstrable and reproducible data, according to the Merriam-Webster dictionary . True to this definition, science aims for measurable results through testing and analysis, a process known as the scientific method. Science is based on fact, not opinion or preferences. The process of science is designed to challenge ideas through research. One important aspect of the scientific process is that it focuses only on the natural world, according to the University of California, Berkeley . Anything that is considered supernatural, or beyond physical reality, does not fit into the definition of science.
When conducting research, scientists use the scientific method to collect measurable, empirical evidence in an experiment related to a hypothesis (often in the form of an if/then statement) that is designed to support or contradict a scientific theory .
"As a field biologist, my favorite part of the scientific method is being in the field collecting the data," Jaime Tanner, a professor of biology at Marlboro College, told Live Science. "But what really makes that fun is knowing that you are trying to answer an interesting question. So the first step in identifying questions and generating possible answers (hypotheses) is also very important and is a creative process. Then once you collect the data you analyze it to see if your hypothesis is supported or not."
The steps of the scientific method go something like this, according to Highline College :
- Make an observation or observations.
- Form a hypothesis — a tentative description of what's been observed, and make predictions based on that hypothesis.
- Test the hypothesis and predictions in an experiment that can be reproduced.
- Analyze the data and draw conclusions; accept or reject the hypothesis or modify the hypothesis if necessary.
- Reproduce the experiment until there are no discrepancies between observations and theory. "Replication of methods and results is my favorite step in the scientific method," Moshe Pritsker, a former post-doctoral researcher at Harvard Medical School and CEO of JoVE, told Live Science. "The reproducibility of published experiments is the foundation of science. No reproducibility — no science."
Some key underpinnings to the scientific method:
- The hypothesis must be testable and falsifiable, according to North Carolina State University . Falsifiable means that there must be a possible negative answer to the hypothesis.
- Research must involve deductive reasoning and inductive reasoning . Deductive reasoning is the process of using true premises to reach a logical true conclusion while inductive reasoning uses observations to infer an explanation for those observations.
- An experiment should include a dependent variable (which does not change) and an independent variable (which does change), according to the University of California, Santa Barbara .
- An experiment should include an experimental group and a control group. The control group is what the experimental group is compared against, according to Britannica .
The process of generating and testing a hypothesis forms the backbone of the scientific method. When an idea has been confirmed over many experiments, it can be called a scientific theory. While a theory provides an explanation for a phenomenon, a scientific law provides a description of a phenomenon, according to The University of Waikato . One example would be the law of conservation of energy, which is the first law of thermodynamics that says that energy can neither be created nor destroyed.
A law describes an observed phenomenon, but it doesn't explain why the phenomenon exists or what causes it. "In science, laws are a starting place," said Peter Coppinger, an associate professor of biology and biomedical engineering at the Rose-Hulman Institute of Technology. "From there, scientists can then ask the questions, 'Why and how?'"
Laws are generally considered to be without exception, though some laws have been modified over time after further testing found discrepancies. For instance, Newton's laws of motion describe everything we've observed in the macroscopic world, but they break down at the subatomic level.
This does not mean theories are not meaningful. For a hypothesis to become a theory, scientists must conduct rigorous testing, typically across multiple disciplines by separate groups of scientists. Saying something is "just a theory" confuses the scientific definition of "theory" with the layperson's definition. To most people a theory is a hunch. In science, a theory is the framework for observations and facts, Tanner told Live Science.
The earliest evidence of science can be found as far back as records exist. Early tablets contain numerals and information about the solar system , which were derived by using careful observation, prediction and testing of those predictions. Science became decidedly more "scientific" over time, however.
1200s: Robert Grosseteste developed the framework for the proper methods of modern scientific experimentation, according to the Stanford Encyclopedia of Philosophy. His works included the principle that an inquiry must be based on measurable evidence that is confirmed through testing.
1400s: Leonardo da Vinci began his notebooks in pursuit of evidence that the human body is microcosmic. The artist, scientist and mathematician also gathered information about optics and hydrodynamics.
1500s: Nicolaus Copernicus advanced the understanding of the solar system with his discovery of heliocentrism. This is a model in which Earth and the other planets revolve around the sun, which is the center of the solar system.
1600s: Johannes Kepler built upon those observations with his laws of planetary motion. Galileo Galilei improved on a new invention, the telescope, and used it to study the sun and planets. The 1600s also saw advancements in the study of physics as Isaac Newton developed his laws of motion.
1700s: Benjamin Franklin discovered that lightning is electrical. He also contributed to the study of oceanography and meteorology. The understanding of chemistry also evolved during this century as Antoine Lavoisier, dubbed the father of modern chemistry , developed the law of conservation of mass.
1800s: Milestones included Alessandro Volta's discoveries regarding electrochemical series, which led to the invention of the battery. John Dalton also introduced atomic theory, which stated that all matter is composed of atoms that combine to form molecules. The basis of modern study of genetics advanced as Gregor Mendel unveiled his laws of inheritance. Later in the century, Wilhelm Conrad Röntgen discovered X-rays , while George Ohm's law provided the basis for understanding how to harness electrical charges.
1900s: The discoveries of Albert Einstein , who is best known for his theory of relativity, dominated the beginning of the 20th century. Einstein's theory of relativity is actually two separate theories. His special theory of relativity, which he outlined in a 1905 paper, " The Electrodynamics of Moving Bodies ," concluded that time must change according to the speed of a moving object relative to the frame of reference of an observer. His second theory of general relativity, which he published as " The Foundation of the General Theory of Relativity ," advanced the idea that matter causes space to curve.
In 1952, Jonas Salk developed the polio vaccine , which reduced the incidence of polio in the United States by nearly 90%, according to Britannica . The following year, James D. Watson and Francis Crick discovered the structure of DNA , which is a double helix formed by base pairs attached to a sugar-phosphate backbone, according to the National Human Genome Research Institute .
2000s: The 21st century saw the first draft of the human genome completed, leading to a greater understanding of DNA. This advanced the study of genetics, its role in human biology and its use as a predictor of diseases and other disorders, according to the National Human Genome Research Institute .
- This video from City University of New York delves into the basics of what defines science.
- Learn about what makes science science in this book excerpt from Washington State University .
- This resource from the University of Michigan — Flint explains how to design your own scientific study.
Merriam-Webster Dictionary, Scientia. 2022. https://www.merriam-webster.com/dictionary/scientia
University of California, Berkeley, "Understanding Science: An Overview." 2022. https://undsci.berkeley.edu/article/0_0_0/intro_01
Highline College, "Scientific method." July 12, 2015. https://people.highline.edu/iglozman/classes/astronotes/scimeth.htm
North Carolina State University, "Science Scripts." https://projects.ncsu.edu/project/bio183de/Black/science/science_scripts.html
University of California, Santa Barbara. "What is an Independent variable?" October 31,2017. http://scienceline.ucsb.edu/getkey.php?key=6045
Encyclopedia Britannica, "Control group." May 14, 2020. https://www.britannica.com/science/control-group
The University of Waikato, "Scientific Hypothesis, Theories and Laws." https://sci.waikato.ac.nz/evolution/Theories.shtml
Stanford Encyclopedia of Philosophy, Robert Grosseteste. May 3, 2019. https://plato.stanford.edu/entries/grosseteste/
Encyclopedia Britannica, "Jonas Salk." October 21, 2021. https://www.britannica.com/ biography /Jonas-Salk
National Human Genome Research Institute, "Phosphate Backbone." https://www.genome.gov/genetics-glossary/Phosphate-Backbone
National Human Genome Research Institute, "What is the Human Genome Project?" https://www.genome.gov/human-genome-project/What
Live Science contributor Ashley Hamer updated this article on Jan. 16, 2022.
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The Scientific Method Tutorial
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The Scientific Method
Steps in the scientific method.
There is a great deal of variation in the specific techniques scientists use explore the natural world. However, the following steps characterize the majority of scientific investigations:
Step 1: Make observations Step 2: Propose a hypothesis to explain observations Step 3: Test the hypothesis with further observations or experiments Step 4: Analyze data Step 5: State conclusions about hypothesis based on data analysis
Each of these steps is explained briefly below, and in more detail later in this section.
Step 1: Make observations
A scientific inquiry typically starts with observations. Often, simple observations will trigger a question in the researcher's mind.
Example: A biologist frequently sees monarch caterpillars feeding on milkweed plants, but rarely sees them feeding on other types of plants. She wonders if it is because the caterpillars prefer milkweed over other food choices.
Step 2: Propose a hypothesis
The researcher develops a hypothesis (singular) or hypotheses (plural) to explain these observations. A hypothesis is a tentative explanation of a phenomenon or observation(s) that can be supported or falsified by further observations or experimentation.
Example: The researcher hypothesizes that monarch caterpillars prefer to feed on milkweed compared to other common plants. (Notice how the hypothesis is a statement, not a question as in step 1.)
Step 3: Test the hypothesis
The researcher makes further observations and/or may design an experiment to test the hypothesis. An experiment is a controlled situation created by a researcher to test the validity of a hypothesis. Whether further observations or an experiment is used to test the hypothesis will depend on the nature of the question and the practicality of manipulating the factors involved.
Example: The researcher sets up an experiment in the lab in which a number of monarch caterpillars are given a choice between milkweed and a number of other common plants to feed on.
Step 4: Analyze data
The researcher summarizes and analyzes the information, or data, generated by these further observations or experiments.
Example: In her experiment, milkweed was chosen by caterpillars 9 times out of 10 over all other plant selections.
Step 5: State conclusions
The researcher interprets the results of experiments or observations and forms conclusions about the meaning of these results. These conclusions are generally expressed as probability statements about their hypothesis.
Example: She concludes that when given a choice, 90 percent of monarch caterpillars prefer to feed on milkweed over other common plants.
Often, the results of one scientific study will raise questions that may be addressed in subsequent research. For example, the above study might lead the researcher to wonder why monarchs seem to prefer to feed on milkweed, and she may plan additional experiments to explore this question. For example, perhaps the milkweed has higher nutritional value than other available plants.
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The Scientific Method Flowchart
The steps in the scientific method are presented visually in the following flow chart. The question raised or the results obtained at each step directly determine how the next step will proceed. Following the flow of the arrows, pass the cursor over each blue box. An explanation and example of each step will appear. As you read the example given at each step, see if you can predict what the next step will be.
Activity: Apply the Scientific Method to Everyday Life Use the steps of the scientific method described above to solve a problem in real life. Suppose you come home one evening and flick the light switch only to find that the light doesnt turn on. What is your hypothesis? How will you test that hypothesis? Based on the result of this test, what are your conclusions? Follow your instructor's directions for submitting your response.
The above flowchart illustrates the logical sequence of conclusions and decisions in a typical scientific study. There are some important points to note about this process:
1. The steps are clearly linked.
The steps in this process are clearly linked. The hypothesis, formed as a potential explanation for the initial observations, becomes the focus of the study. The hypothesis will determine what further observations are needed or what type of experiment should be done to test its validity. The conclusions of the experiment or further observations will either be in agreement with or will contradict the hypothesis. If the results are in agreement with the hypothesis, this does not prove that the hypothesis is true! In scientific terms, it "lends support" to the hypothesis, which will be tested again and again under a variety of circumstances before researchers accept it as a fairly reliable description of reality.
2. The same steps are not followed in all types of research.
The steps described above present a generalized method followed in a many scientific investigations. These steps are not carved in stone. The question the researcher wishes to answer will influence the steps in the method and how they will be carried out. For example, astronomers do not perform many experiments as defined here. They tend to rely on observations to test theories. Biologists and chemists have the ability to change conditions in a test tube and then observe whether the outcome supports or invalidates their starting hypothesis, while astronomers are not able to change the path of Jupiter around the Sun and observe the outcome!
3. Collected observations may lead to the development of theories.
When a large number of observations and/or experimental results have been compiled, and all are consistent with a generalized description of how some element of nature operates, this description is called a theory. Theories are much broader than hypotheses and are supported by a wide range of evidence. Theories are important scientific tools. They provide a context for interpretation of new observations and also suggest experiments to test their own validity. Theories are discussed in more detail in another section.
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The Scientific Method in Detail
In the sections that follow, each step in the scientific method is described in more detail.
Step 1: Observations
Observations in science.
An observation is some thing, event, or phenomenon that is noticed or observed. Observations are listed as the first step in the scientific method because they often provide a starting point, a source of questions a researcher may ask. For example, the observation that leaves change color in the fall may lead a researcher to ask why this is so, and to propose a hypothesis to explain this phenomena. In fact, observations also will provide the key to answering the research question.
In science, observations form the foundation of all hypotheses, experiments, and theories. In an experiment, the researcher carefully plans what observations will be made and how they will be recorded. To be accepted, scientific conclusions and theories must be supported by all available observations. If new observations are made which seem to contradict an established theory, that theory will be re-examined and may be revised to explain the new facts. Observations are the nuts and bolts of science that researchers use to piece together a better understanding of nature.
Observations in science are made in a way that can be precisely communicated to (and verified by) other researchers. In many types of studies (especially in chemistry, physics, and biology), quantitative observations are used. A quantitative observation is one that is expressed and recorded as a quantity, using some standard system of measurement. Quantities such as size, volume, weight, time, distance, or a host of others may be measured in scientific studies.
Some observations that researchers need to make may be difficult or impossible to quantify. Take the example of color. Not all individuals perceive color in exactly the same way. Even apart from limiting conditions such as colorblindness, the way two people see and describe the color of a particular flower, for example, will not be the same. Color, as perceived by the human eye, is an example of a qualitative observation.
Qualitative observations note qualities associated with subjects or samples that are not readily measured. Other examples of qualitative observations might be descriptions of mating behaviors, human facial expressions, or "yes/no" type of data, where some factor is present or absent. Though the qualities of an object may be more difficult to describe or measure than any quantities associated with it, every attempt is made to minimize the effects of the subjective perceptions of the researcher in the process. Some types of studies, such as those in the social and behavioral sciences (which deal with highly variable human subjects), may rely heavily on qualitative observations.
Question: Why are observations important to science?
Limits of Observations
Because all observations rely to some degree on the senses (eyes, ears, or steady hand) of the researcher, complete objectivity is impossible. Our human perceptions are limited by the physical abilities of our sense organs and are interpreted according to our understanding of how the world works, which can be influenced by culture, experience, or education. According to science education specialist, George F. Kneller, "Surprising as it may seem, there is no fact that is not colored by our preconceptions" ("A Method of Enquiry," from Science and Its Ways of Knowing [Upper Saddle River: Prentice-Hall Inc., 1997], 15).
Observations made by a scientist are also limited by the sensitivity of whatever equipment he is using. Research findings will be limited at times by the available technology. For example, Italian physicist and philosopher Galileo Galilei (15641642) was reportedly the first person to observe the heavens with a telescope. Imagine how it must have felt to him to see the heavens through this amazing new instrument! It opened a window to the stars and planets and allowed new observations undreamed of before.
In the centuries since Galileo, increasingly more powerful telescopes have been devised that dwarf the power of that first device. In the past decade, we have marveled at images from deep space , courtesy of the Hubble Space Telescope, a large telescope that orbits Earth. Because of its view from outside the distorting effects of the atmosphere, the Hubble can look 50 times farther into space than the best earth-bound telescopes, and resolve details a tenth of the size (Seeds, Michael A., Horizons: Exploring the Universe , 5 th ed. [Belmont: Wadsworth Publishing Company, 1998], 86-87).
Construction is underway on a new radio telescope that scientists say will be able to detect electromagnetic waves from the very edges of the universe! This joint U.S.-Mexican project may allow us to ask questions about the origins of the universe and the beginnings of time that we could never have hoped to answer before. Completion of the new telescope is expected by the end of 2001.
Although the amount of detail observed by Galileo and today's astronomers is vastly different, the stars and their relationships have not changed very much. Yet with each technological advance, the level of detail of observation has been increased, and with it, the power to answer more and more challenging questions with greater precision.
Question: What are some of the differences between a casual observation and a 'scientific observation'?
Step 2: The Hypothesis
A hypothesis is a statement created by the researcher as a potential explanation for an observation or phenomena. The hypothesis converts the researcher's original question into a statement that can be used to make predictions about what should be observed if the hypothesis is true. For example, given the hypothesis, "exposure to ultraviolet (UV) radiation increases the risk of skin cancer," one would predict higher rates of skin cancer among people with greater UV exposure. These predictions could be tested by comparing skin cancer rates among individuals with varying amounts of UV exposure. Note how the hypothesis itself determines what experiments or further observations should be made to test its validity. Results of tests are then compared to predictions from the hypothesis, and conclusions are stated in terms of whether or not the data supports the hypothesis. So the hypothesis serves a guide to the full process of scientific inquiry.
The Qualities of a Good Hypothesis
- A hypothesis must be testable or provide predictions that are testable. It can potentially be shown to be false by further observations or experimentation.
- A hypothesis should be specific. If it is too general it cannot be tested, or tests will have so many variables that the results will be complicated and difficult to interpret. A well-written hypothesis is so specific it actually determines how the experiment should be set up.
- A hypothesis should not include any untested assumptions if they can be avoided. The hypothesis itself may be an assumption that is being tested, but it should be phrased in a way that does not include assumptions that are not tested in the experiment.
- It is okay (and sometimes a good idea) to develop more than one hypothesis to explain a set of observations. Competing hypotheses can often be tested side-by-side in the same experiment.
Question: Why is the hypothesis important to the scientific method?
grow well in a lighted incubator maintained at 90 F. A culture of was accidentally left uncovered overnight on a laboratory bench where it was dark and temperatures fluctuated between 65 F and 68 F. When the technician returned in the morning, all the cells were dead. Which of the following statements is the hypothesis to explain why the cells died, based on this observation? | cells to die. | |
Step 3: Testing the Hypothesis
A hypothesis may be tested in one of two ways: by making additional observations of a natural situation, or by setting up an experiment. In either case, the hypothesis is used to make predictions, and the observations or experimental data collected are examined to determine if they are consistent or inconsistent with those predictions. Hypothesis testing, especially through experimentation, is at the core of the scientific process. It is how scientists gain a better understanding of how things work.
Testing a Hypothesis by Observation
Some hypotheses may be tested through simple observation. For example, a researcher may formulate the hypothesis that the sun always rises in the east. What might an alternative hypothesis be? If his hypothesis is correct, he would predict that the sun will rise in the east tomorrow. He can easily test such a prediction by rising before dawn and going out to observe the sunrise. If the sun rises in the west, he will have disproved the hypothesis. He will have shown that it does not hold true in every situation. However, if he observes on that morning that the sun does in fact rise in the east, he has not proven the hypothesis. He has made a single observation that is consistent with, or supports, the hypothesis. As a scientist, to confidently state that the sun will always rise in the east, he will want to make many observations, under a variety of circumstances. Note that in this instance no manipulation of circumstance is required to test the hypothesis (i.e., you aren't altering the sun in any way).
Testing a Hypothesis by Experimentation
An experiment is a controlled series of observations designed to test a specific hypothesis. In an experiment, the researcher manipulates factors related to the hypothesis in such a way that the effect of these factors on the observations (data) can be readily measured and compared. Most experiments are an attempt to define a cause-and-effect relationship between two factors or eventsto explain why something happens. For example, with the hypothesis "roses planted in sunny areas bloom earlier than those grown in shady areas," the experiment would be testing a cause-and-effect relationship between sunlight and time of blooming.
A major advantage of setting up an experiment versus making observations of what is already available is that it allows the researcher to control all the factors or events related to the hypothesis, so that the true cause of an event can be more easily isolated. In all cases, the hypothesis itself will determine the way the experiment will be set up. For example, suppose my hypothesis is "the weight of an object is proportional to the amount of time it takes to fall a certain distance." How would you test this hypothesis?
The Qualities of a Good Experiment
- The experiment must be conducted on a group of subjects that are narrowly defined and have certain aspects in common. This is the group to which any conclusions must later be confined. (Examples of possible subjects: female cancer patients over age 40, E. coli bacteria, red giant stars, the nicotine molecule and its derivatives.)
- All subjects of the experiment should be (ideally) completely alike in all ways except for the factor or factors that are being tested. Factors that are compared in scientific experiments are called variables. A variable is some aspect of a subject or event that may differ over time or from one group of subjects to another. For example, if a biologist wanted to test the effect of nitrogen on grass growth, he would apply different amounts of nitrogen fertilizer to several plots of grass. The grass in each of the plots should be as alike as possible so that any difference in growth could be attributed to the effect of the nitrogen. For example, all the grass should be of the same species, planted at the same time and at the same density, receive the same amount of water and sunlight, and so on. The variable in this case would be the amount of nitrogen applied to the plants. The researcher would not compare differing amounts of nitrogen across different grass species to determine the effect of nitrogen on grass growth. What is the problem with using different species of plants to compare the effect of nitrogen on plant growth? There are different kinds of variables in an experiment. A factor that the experimenter controls, and changes intentionally to determine if it has an effect, is called an independent variable . A factor that is recorded as data in the experiment, and which is compared across different groups of subjects, is called a dependent variable . In many cases, the value of the dependent variable will be influenced by the value of an independent variable. The goal of the experiment is to determine a cause-and-effect relationship between independent and dependent variablesin this case, an effect of nitrogen on plant growth. In the nitrogen/grass experiment, (1) which factor was the independent variable? (2) Which factor was the dependent variable?
- Nearly all types of experiments require a control group and an experimental group. The control group generally is not changed in any way, but remains in a "natural state," while the experimental group is modified in some way to examine the effect of the variable which of interest to the researcher. The control group provides a standard of comparison for the experimental groups. For example, in new drug trials, some patients are given a placebo while others are given doses of the drug being tested. The placebo serves as a control by showing the effect of no drug treatment on the patients. In research terminology, the experimental groups are often referred to as treatments , since each group is treated differently. In the experimental test of the effect of nitrogen on grass growth, what is the control group? In the example of the nitrogen experiment, what is the purpose of a control group?
- In research studies a great deal of emphasis is placed on repetition. It is essential that an experiment or study include enough subjects or enough observations for the researcher to make valid conclusions. The two main reasons why repetition is important in scientific studies are (1) variation among subjects or samples and (2) measurement error.
Variation among Subjects
There is a great deal of variation in nature. In a group of experimental subjects, much of this variation may have little to do with the variables being studied, but could still affect the outcome of the experiment in unpredicted ways. For example, in an experiment designed to test the effects of alcohol dose levels on reflex time in 18- to 22-year-old males, there would be significant variation among individual responses to various doses of alcohol. Some of this variation might be due to differences in genetic make-up, to varying levels of previous alcohol use, or any number of factors unknown to the researcher.
Because what the researcher wants to discover is average dose level effects for this group, he must run the test on a number of different subjects. Suppose he performed the test on only 10 individuals. Do you think the average response calculated would be the same as the average response of all 18- to 22-year-old males? What if he tests 100 individuals, or 1,000? Do you think the average he comes up with would be the same in each case? Chances are it would not be. So which average would you predict would be most representative of all 18- to 22-year-old males?
A basic rule of statistics is, the more observations you make, the closer the average of those observations will be to the average for the whole population you are interested in. This is because factors that vary among a population tend to occur most commonly in the middle range, and least commonly at the two extremes. Take human height for example. Although you may find a man who is 7 feet tall, or one who is 4 feet tall, most men will fall somewhere between 5 and 6 feet in height. The more men we measure to determine average male height, the less effect those uncommon extreme (tall or short) individuals will tend to impact the average. Thus, one reason why repetition is so important in experiments is that it helps to assure that the conclusions made will be valid not only for the individuals tested, but also for the greater population those individuals represent.
"The use of a sample (or subset) of a population, an event, or some other aspect of nature for an experimental group that is not large enough to be representative of the whole" is called sampling error (Starr, Cecie, Biology: Concepts and Applications , 4 th ed. [Pacific Cove: Brooks/Cole, 2000], glossary). If too few samples or subjects are used in an experiment, the researcher may draw incorrect conclusions about the population those samples or subjects represent.
Use the jellybean activity below to see a simple demonstration of samping error.
Directions: There are 400 jellybeans in the jar. If you could not see the jar and you initially chose 1 green jellybean from the jar, you might assume the jar only contains green jelly beans. The jar actually contains both green and black jellybeans. Use the "pick 1, 5, or 10" buttons to create your samples. For example, use the "pick" buttons now to create samples of 2, 13, and 27 jellybeans. After you take each sample, try to predict the ratio of green to black jellybeans in the jar. How does your prediction of the ratio of green to black jellybeans change as your sample changes?
Measurement Error
The second reason why repetition is necessary in research studies has to do with measurement error. Measurement error may be the fault of the researcher, a slight difference in measuring techniques among one or more technicians, or the result of limitations or glitches in measuring equipment. Even the most careful researcher or the best state-of-the-art equipment will make some mistakes in measuring or recording data. Another way of looking at this is to say that, in any study, some measurements will be more accurate than others will. If the researcher is conscientious and the equipment is good, the majority of measurements will be highly accurate, some will be somewhat inaccurate, and a few may be considerably inaccurate. In this case, the same reasoning used above also applies here: the more measurements taken, the less effect a few inaccurate measurements will have on the overall average.
Step 4: Data Analysis
In any experiment, observations are made, and often, measurements are taken. Measurements and observations recorded in an experiment are referred to as data . The data collected must relate to the hypothesis being tested. Any differences between experimental and control groups must be expressed in some way (often quantitatively) so that the groups may be compared. Graphs and charts are often used to visualize the data and to identify patterns and relationships among the variables.
Statistics is the branch of mathematics that deals with interpretation of data. Data analysis refers to statistical methods of determining whether any differences between the control group and experimental groups are too great to be attributed to chance alone. Although a discussion of statistical methods is beyond the scope of this tutorial, the data analysis step is crucial because it provides a somewhat standardized means for interpreting data. The statistical methods of data analysis used, and the results of those analyses, are always included in the publication of scientific research. This convention limits the subjective aspects of data interpretation and allows scientists to scrutinize the working methods of their peers.
Why is data analysis an important step in the scientific method?
Step 5: Stating Conclusions
The conclusions made in a scientific experiment are particularly important. Often, the conclusion is the only part of a study that gets communicated to the general public. As such, it must be a statement of reality, based upon the results of the experiment. To assure that this is the case, the conclusions made in an experiment must (1) relate back to the hypothesis being tested, (2) be limited to the population under study, and (3) be stated as probabilities.
The hypothesis that is being tested will be compared to the data collected in the experiment. If the experimental results contradict the hypothesis, it is rejected and further testing of that hypothesis under those conditions is not necessary. However, if the hypothesis is not shown to be wrong, that does not conclusively prove that it is right! In scientific terms, the hypothesis is said to be "supported by the data." Further testing will be done to see if the hypothesis is supported under a number of trials and under different conditions.
If the hypothesis holds up to extensive testing then the temptation is to claim that it is correct. However, keep in mind that the number of experiments and observations made will only represent a subset of all the situations in which the hypothesis may potentially be tested. In other words, experimental data will only show part of the picture. There is always the possibility that a further experiment may show the hypothesis to be wrong in some situations. Also, note that the limits of current knowledge and available technologies may prevent a researcher from devising an experiment that would disprove a particular hypothesis.
The researcher must be sure to limit his or her conclusions to apply only to the subjects tested in the study. If a particular species of fish is shown to consume their young 90 percent of the time when raised in captivity, that doesn't necessarily mean that all fish will do so, or that this fish's behavior would be the same in its native habitat.
Finally, the conclusions of the experiment are generally stated as probabilities. A careful scientist would never say, "drug x kills cancer cells;" she would more likely say, "drug x was shown to destroy 85 percent of cancerous skin cells in rats in lab trials." Notice how very different these two statements are. There is a tendency in the media and in the general public to gravitate toward the first statement. This makes a terrific headline and is also easy to interpret; it is absolute. Remember though, in science conclusions must be confined to the population under study; broad generalizations should be avoided. The second statement is sound science. There is data to back it up. Later studies may reveal a more universal effect of the drug on cancerous cells, or they may not. Most researchers would be unwilling to stake their reputations on the first statement.
As a student, you should read and interpret popular press articles about research studies very carefully. From the text, can you determine how the experiment was set up and what variables were measured? Are the observations and data collected appropriate to the hypothesis being tested? Are the conclusions supported by the data? Are the conclusions worded in a scientific context (as probability statements) or are they generalized for dramatic effect? In any researched-based assignment, it is a good idea to refer to the original publication of a study (usually found in professional journals) and to interpret the facts for yourself.
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Qualities of a Good Experiment
- narrowly defined subjects
- all subjects treated alike except for the factor or variable being studied
- a control group is used for comparison
- measurements related to the factors being studied are carefully recorded
- enough samples or subjects are used so that conclusions are valid for the population of interest
- conclusions made relate back to the hypothesis, are limited to the population being studied, and are stated in terms of probabilities
by Stephen S. Carey. |
Scientific Method: What it is, How to Use It: Scientific Method
- Scientific Method
- Step 1: Question
- Step 2: Research
- Step 3: Hypothesis
- Step 4: Experiment
- Step 5: Data
- Step 6: Conclusion
What is the Scientific Method?
The scientific method is a standardized way of making observations, gathering data, forming theories, testing predictions, and interpreting results. Does this mean all scientists follow this exact process? No. Some areas of science can be more easily tested than others.
For example, scientists studying how stars change as they age or how dinosaurs digested their food cannot fast-forward a star's life by a million years or run medical exams on feeding dinosaurs to test their hypotheses. When direct experimentation is not possible, scientists modify the scientific method. In fact, there are probably as many versions of the scientific method as there are scientists!
But even when modified, the goal remains the same: to discover cause and effect relationships by asking questions, carefully gathering and examining the evidence, and seeing if all the available information can be combined in to a logical answer.
The Four Factors of Conducting Good Scientific Research
- Replication
- Falsifiable
- Parsimonious
1. Research must be Replicable, meaning that other researchers must be able to repeat the study and get the same results. This is why in a scientific study, researchers take the time not only to describe their results but also the methods they used to achieve their results.
As scientists do their research and make sure that it's replicable, they'll develop a theory and translate that theory into a hypothesis. A Hypothesis is a testable prediction of what will happen given a certain set of conditions. A good theory must do two things: organize many observations in a logical way and allow researchers to come up with clear predictions to check the theory.
A good theory or hypothesis also must be Falsifiable , which means that it must be stated in a way that makes it possible to reject it. In other words, we have to be able to prove a theory or hypothesis wrong.
Theories and hypotheses need to be falsifiable because otherwise research will present confirmation bias. Researchers who display Confirmation Bias look for and accept evidence that supports what they want to believe and ignore or reject evidence that refutes their beliefs.
Falsifiability doesn’t mean that there are currently arguments against a theory, only that it is possible to imagine some kind of argument which would invalidate it. Falsifiability says nothing about an argument's inherent validity or correctness. It is only the basic requirement of a theory which allows it to be considered scientific. An important note however, is that falsifiability is not simply any claim that has yet to be proven true.
- Does Science Need Falsifiability? An article by Kate Becker in PBS's Nova explains the value and necessity of making scientific research falsifiable.
By stating hypotheses precisely, scientists ensure that they can replicate their own and others’ research. To make hypotheses more precise, researchers use operational definitions to define the variables they study. Operational Definitions state exactly how a variable will be measured.
Precision and accuracy are two ways that scientists think about error. Accuracy refers to how close a measurement is to the true or accepted value. Precision refers to how close measurements of the same item are to each other. Precision is independent of accuracy which means it is possible to be very precise but not very accurate , and it is also possible to be accurate without being precise. The best quality scientific observations are both accurate and precise.
The easiest way to illustrate the difference between precision and accuracy is with the analogy of a dartboard.
- In example A, the darts are neither close to the bulls-eye, nor close to each other, meaning there is neither accuracy, nor precision.
- In example B, all of the darts land very close together, but far from the bulls-eye. There is precision, but not accuracy
- In example C, the darts are all about an equal distance from and spaced equally around the bulls-eye there is accuracy because the average of the darts would be in the bulls-eye. This represents data that is accurate, but not precise.
- In example D, the darts land close to the bulls-eye and close together. Meaning there is both accuracy and precision.
Parsimonious means “being thrifty or stingy.” A person who values parsimony will apply the thriftiest or most logically economical explanation for a set of phenomena.
The Principle Of Parsimony , also called Occam’s Razor , maintains that researchers should apply the simplest explanation possible to any set of observations. For instance, scientists try to explain results by using well-accepted theories instead of elaborate new hypotheses. Parsimony prevents researchers from inventing and pursuing outlandish theories.
What Parsimony means in practice is we should go with the weight of the evidence available to us. This will probably seem very obvious, but in practice it is essential that we have a philosophically justified method of choosing between explanations of our data. After all, when there is good evidence to support one idea and only slightly less good evidence to support another – can you really chose between them? Well, yes. You *MUST* take number 1.
Scientific Method (Infographic)
Scientific Method (Video)
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Learn how to use the scientific method to explore observations and answer questions. The web page explains the six steps of the scientific method with examples, resources, and frequently asked questions.
The formulation and testing of a hypothesis is part of the scientific method, the approach scientists use when attempting to understand and test ideas about natural phenomena. The generation of a hypothesis frequently is described as a creative process and is based on existing scientific knowledge, intuition, or experience.
The scientific method is a step-by-step process for obtaining knowledge through observation, experimentation, and hypothesis testing. Learn the seven steps of the scientific method, see examples of psychological research, and understand the role of observation in the scientific method.
Learn how to use the scientific method to ask questions, test hypotheses, and communicate results. The web page explains each step, provides examples, and discusses variables and types of hypotheses.
In science, a hypothesis is part of the scientific method. It is a prediction or explanation that is tested by an experiment. ... In the study of logic, a hypothesis is an if-then proposition, typically written in the form, "If X, then Y." In common usage, a hypothesis is simply a proposed explanation or prediction, which may or may not be tested.
The scientific method is critical to the development of scientific theories, which explain empirical (experiential) laws in a scientifically rational manner.In a typical application of the scientific method, a researcher develops a hypothesis, tests it through various means, and then modifies the hypothesis on the basis of the outcome of the tests and experiments.
Learn the six steps of the scientific method: observation, question, hypothesis, experiment, results, and conclusion. See how scientists use this process to answer questions about the natural world.
The scientific method is a system to ask and answer questions about the natural world by making observations, asking a question, formulating a hypothesis, designing and performing an experiment, and drawing a conclusion. Learn the steps of the scientific method and how to apply them in different situations.
The scientific method is an empirical method for acquiring knowledge that involves observation, scepticism, hypothesis, experiment, and falsifiability. Learn about the history, philosophy, and applications of the scientific method, as well as its limits and controversies.
A hypothesis is a statement that explains the predictions and reasoning of your research—an "educated guess" about how your scientific experiments will end. As a fundamental part of the scientific method, a good hypothesis is carefully written, but even the simplest ones can be difficult to put into words.
Learn how to write a hypothesis for scientific research, based on a research question, existing theories and data. Follow the steps to formulate, refine and phrase your hypothesis in different ways, and see examples of null and alternative hypotheses.
Learn what a hypothesis is, how to write one, and the different types of hypotheses you might use in psychology research. A hypothesis is a testable prediction about the relationship between variables that guides the research process.
Once you have a solid hypothesis, the next step of the scientific method is to put this hunch to the test by collecting data. The exact methods used to investigate a hypothesis depend on exactly what is being studied. There are two basic forms of research that a psychologist might utilize: descriptive research or experimental research.
The scientific method is the process by which scientists of all fields attempt to explain the phenomena in the world. It is how science is conducted--through experimentation. Generally, the scientific method refers to a set of steps whereby a scientist can form a conjecture (the hypothesis) for why something functions the way it does and then test their hypothesis. It is an empirical process ...
Learn what the scientific method is, how it works, and why it's important for answering questions about the world. Follow the steps of the scientific method with an example of fixing a broken toaster.
When conducting research, scientists use the scientific method to collect measurable, empirical evidence in an experiment related to a hypothesis (often in the form of an if/then statement) that ...
A tentative decision is a hypothesis that can be supported or falsified by further observations or experiments. Learn the steps of the scientific method, including how to propose, test, and analyze hypotheses, and see examples and activities.
Learn the definition, steps, and examples of the scientific method, a process of gathering knowledge and explaining phenomena through observation, question, hypothesis, experiment, data analysis, and conclusion. The scientific method is used by scientists and non-scientists in various situations and can yield conflicting evidence.
The scientific method is a standardized way of making observations, gathering data, forming theories, testing predictions, and interpreting results. Does this mean all scientists follow this exact process? No. ... A Hypothesis is a testable prediction of what will happen given a certain set of conditions. A good theory must do two things ...
Though you may hear the terms "theory" and "hypothesis" used interchangeably, these two scientific terms have drastically different meanings in the world of science. Articles Videos
Mr. C shows you the difference between a bad hypothesis and a good one. He also talks about why forming a good hypothesis is so important to the Scientific M...
A hypothesis is fundamental to the scientific method. A hypothesis can take the form of an explanation or a prediction. There are several ways to break down the steps of the scientific method, but it always involves forming a hypothesis, testing the hypothesis, and determining whether or not the hypothesis is correct.
Here are 50 science project ideas that apply the scientific method across different fields like biology, chemistry, physics, and environmental science. Each project involves forming a hypothesis, conducting experiments, gathering data, and drawing conclusions. Biology Effect of Light on Plant Growth - Hypothesize how different light conditions affect plant growth rates. Does Music Affect Plant
The characteristics of a reasonable hypothesis are included in the standardized steps of observation, question, hypothesis, experiment/prediction, test, refine, or repeat. The wonderful part about the characteristics of a good hypothesis is that it can be testable and unambiguous, have variable predictions or tasks that can be replicated, and ...