The Scientific Method
Objectives
- Apply knowledge of scientific theories to problem-solving applications.
- Identify and utilize background data.
- Develop a hypothesis for a scientific experiment.
- Identify the control, independent, and dependent variables for an experiment.
- Predict next steps for a scientific study using data.
- Draw conclusions based on experimental data.
“If we knew what we were doing it wouldn’t be called research.”
– taken from a sticker
The Scientific Method
The scientific method is the systematic way scientists study, learn, process, and report on their findings. It’s an agreed-upon and structured way to study the world around us and report what we know. While the scientific method scientists use and we will learn in this course is very structured, everyone uses a simplified version of the scientific method daily to collect data, make decisions, and develop and test new ideas.
Example 1
You use the scientific method to determine why your car won’t start. You may turn on your headlights to see if the battery is dead. This is an example of forming a hypothesis and performing an experiment.
Hypothesis: My car won’t start because the battery is dead.
Experiment: Turn on the headlights to see if they turn on. If they turn on, the battery is not dead (reject the hypothesis). If they don’t turn on, the battery is dead (accept the hypothesis).
If you determine the problem isn’t the battery, you form a new hypothesis, such as checking to see if you have enough gas. This goes on until you identify why the car won’t start.
Example 2
Parents use the scientific method to determine why their newborn baby is crying. They will check their baby’s diaper if they think it needs to be changed.
Hypothesis: The baby’s diaper is dirty/wet.
Experiment: Check the diaper. If the diaper is wet/dirty, change it and see if they stop crying. If it’s dry/empty, reject the hypothesis and form a new one, such as the baby is hungry.
What they observe through experimentation (the diaper is full or the baby takes the bottle) tells them if their hypothesis is correct or not.
Example 3
Business people use the scientific method to take what they know, conduct market research, and develop a new idea for a product. They then use that research and experiment with different concepts to develop the product for the market. Finally, they present that product and market it for sale.
The Scientific Method in Action
Most of the science we encounter in our daily lives has been studied and tested repeatedly. This gives us a comfortable certainty about the world that is inaccurate. We don’t often get a front row seat to the turmoil that exists on the front lines of scientific discovery. This was evident during the COVID-19 pandemic.
In real time, we saw scientists study a new virus and learn more information about it every day. Every new piece of information resulted in changes to how scientists thought the virus was transmitted between people, impacted the human body, and how to treat it. Over time, scientists learned enough that they were able to take what they knew about RNA vaccines and develop a way to apply it to prevent the spread of the virus. This is why what we knew about the virus, what we could do to prevent the spread, and how we could treat the sick changed so quickly. Scientists were constantly learning new information, which changed their recommendations on treatment and prevention. This is what learning looks like. It’s not that scientists didn’t know what they were doing; it’s that we were watching them learn in real time. Learning can be a messy process. It requires patience, work, and time. It took scientists time to gather new information about COVID-19, adjust their analysis and recommendations based on what they learned, and then develop and test vaccines and treatments. What was unknown and messy in 2020 is now much more researched and organized in 2026.
Steps To the Scientific Method
The scientific method is a cyclic process involving the following steps:
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Make An Observation
What did you see happen? Scientists collect all applicable data in an organized fashion for later reference. This is done in a physical lab notebook or in a program designed to record experimental data.
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Ask a Question
This defines the problem observed and helps scientists determine their next steps.
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Conduct Background Research
What have others reported about this phenomenon previously? Is there any published scientific evidence by others? This can be done via the internet, through databases, at the library, or through various other research avenues.
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Form a Hypothesis
A hypothesis is a tentative prediction that explains a phenomenon. A hypothesis is a statement that is testable through experimentation and falsifiable, or can be proven wrong. A hypothesis commonly, but not always, follows an If-Then Structure, “If [I change this], then [this will happen]. A hypothesis will always state the change and the predicted outcome for the experiment. If a hypothesis is proven true, then further experimentation is done to collect more data and confirm reproducibility. If experimentation shows the hypothesis is incorrect, scientists will either reject the hypothesis and recreate it based on the new data or will revise their hypothesis to align with their results. It is ok if a hypothesis is proven incorrect. This is the great thing about science: it allows for reexamination, revisions, and adjustments as scientists learn about the phenomena in our universe.
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Conduct an Experiment
The experiment should directly test the hypothesis. The experiment is repeated many times to collect more data and make sure the same result is observed all the time. Experimental results should always be reproducible through many experimental trials.
- Analyze Results
Reject or accept the hypothesis based on the data collected. All conclusions should be based on the results of experimentation.
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Report Results
Scientists report their results in scientific journals, at conferences, in theses and dissertations, on discussion boards, and in various other ways. If you participated in a science fair in elementary or high school, you presented your experimental results at the science fair.
Video 1 discusses the scientific method and demonstrates how to apply it.
Video 1 – The Scientific Method: Steps, Examples, Tips, and Exercise
The Scientific Method is a Cyclic Process
The scientific method is not a linear process. It is a cyclical process that will repeat the steps outlined above as needed. Brené Brown, a renowned social scientist at the University of Houston, captured the essence of thinking like a scientist:
“Thinking like a scientist involves more than just reacting with an open mind. It means being actively open-minded. It requires searching for reasons why we might be wrong – not for reasons why we might be right – and revisiting your views based on what we learn.” – From Strong Ground by Brené Brown, page 72.
Figure 1 illustrates the cyclic nature of the scientific method. The first three steps of the scientific method can happen in any order and are often repeated throughout the experimental process as necessary. Scientists are constantly doing additional background research, making new observations, and asking new questions throughout any research project.
Figure 1.0 – The Scientific Method
If the data collected during the experiment does not support the hypothesis, then it is necessary to either develop a new hypothesis and test it (repeat steps 3 through 6), revise your hypothesis based on what you observed and conduct additional testing to verify, or reject your hypothesis and abandon the research. The data does support the hypothesis; more data is collected until eventually enough information exists to develop a theory and report the experimental findings to the scientific community.
Please note that different sources will list a different number of steps to the scientific method. No matter how many numeric steps anyone may indicate are involved in the scientific method, the process is basically always the same.
Hypothesis, Theory, and Law
The terms hypothesis, theory, and law are terms used heavily in scientific research and literature. The way they are used in daily conversation is not the same as they are used by scientists. We already learned what a hypothesis is. Now, let’s discuss theories and laws.
- A theory is a unifying principle that explains a group of facts, but is still being tested. An example of this is the Theory of Relativity, which helps to explain how different quantities are measured relative to space and time (E=mc2). Much data has been collected about this; however, new information is always being collected that causes minor revisions to this theory.
- A scientific law is a statement about a set of phenomena that always occurs the same way under the same conditions. An example of this is the Law of Gravity. All objects have a gravitational force, pulling them towards each other. We are most familiar with the gravitational pull of our own planet, which pulls us towards the planet’s center. Laws only apply under very specific conditions. If those conditions are not present, the law does not apply.
Video 2 provides additional information on the difference between a scientific theory and a scientific law. Video 3 discusses the difference between facts, a hypothesis, a theory, and a law. You must understand these basic scientific terms to use them properly in scientific conversation. The way they are used in daily conversation is not the same as how scientists use them.
Video 2 – What’s the difference between a scientific law and a theory?
Video 3 – Fact vs. Theory vs. Hypothesis vs. Law…EXPLAINED!
Designing an Experiment
When developing an experiment, typically certain aspects of the experiment are held constant while other aspects are changed. It is important not to change too many aspects of an experiment at once, or the data may not be conclusive or clear.
- The control is the portion of the experiment that does not vary. For instance, if you want to determine how quickly fabric will fade in the sun, it would be necessary to keep a sample of the fabric away from sunlight so the original color can be compared to the other samples that were exposed to the sunlight.
- The independent variable is the portion of the experiment that is changed. This causes what will happen in the experiment. If you placed three pieces of the fabric in the sun for different amounts of time, the amount of fading that occurs would vary between the pieces of fabric. In this instance, the independent variable would be the amount of time each piece of fabric was left in the sun.
- The dependent variable is the outcome, or results, of the experiment. It is dependent on the independent variable. The dependent variable in our fabric experiment would be how much the fabric color faded. In this class, you will be required to determine the dependent and independent variables for the experiments we conduct. You will be required to identify these variables in formal lab reports, on laboratory assignments, and exams.
- There are also controlled variables. These are variables that are kept exactly the same for all of the items being tested. Examples of controlled variables in our fabric experiment would include using the same color fabric for each test and cutting all the fabric samples to the same size.
Data Collection
Scientists need to collect clear and organized data on their experimental findings to draw conclusions and develop their theories. There are two general types of data that scientists collect: qualitative data and quantitative data.
- Qualitative data is comprised of general observations about the experiment being conducted. This includes shape, color, relative size (large, medium, small), etc.
- Quantitative data is comprised of specific measurements involving numbers that have been collected during the experiment. Examples of quantitative data include volume, density, blood pressure, and temperature. It is important to include units with quantitative data, so other people who read the data will know how it was measured.
Both of these types of data help to develop a picture of what is occurring and why it is happening when a phenomenon is observed. Always be sure to write down all of your observations and the data you collect when experimenting. Do not rely on your memory to recall any information when collecting data because memories are not always reliable or accurate.
This Week in the Lab
During this week’s activity, your instructor will lead you through an interactive scientific case study where you will develop a hypothesis, determine possible next steps for research, and draw conclusions based on the information presented. As this activity is conducted, remember there is no right or wrong hypothesis or incorrect direction of study. If the data don’t support a hypothesis, it is simply revised or recreated. The important thing is that the data collected supports the conclusions.
Assignment
- Complete the PCBs in the Alaskan Frontier Case Study – This interactive case study is linked in Module 2 in Brightspace. It guides you through the application of the scientific method. This case study is based on the work of real graduate students and Ph.D. research. As you complete this case study, you ARE the scientist conducting research. Notice how we work through the scientific method as we learn more information about how PCBs found their way into remote areas of Alaska. Please allow 60-90 minutes to complete this case study.
- Complete the Scientific Method Electronic Assignment provided on Brightspace. This assignment is worth 10 points. This assignment will appear after you have completed the case study. If you don’t see it on Brightspace and you have completed the case study, please refresh your webpage.
Photo by Hari Nandakumar on Unsplash
References
Be Smart. (2015, September 21). Fact Vs Theory vs Hypothesis vs Law…EXPLAINED!. [Video]. YouTube. https://youtu.be/lqk3TKuGNBA?si=dZAamup8edS4rsNt
Brown, B. (2025). Strong ground : the lessons of daring leadership, the tenacity of paradox, and the wisdom of the human spirit (First edition.). Random House.
Sprouts. (2017, October 5). The scientific method: Steps, examples, tips, and exercise [Video]. YouTube. https://www.youtube.com/watch?v=yi0hwFDQTSQ
TED-Ed. (2015, November 19). What’s the difference between a scientific law and theory? [Video]. YouTube. https://www.youtube.com/watch?v=GyN2RhbhiEU
Tessmer, M. (2005). PCBs in the Final Frontier: A Case Study on the Scientific Method. Journal of College Science Teaching, October 2025, 34-36. https://www.nsta.org/resources/pcbs-last-frontier-case-study-scientific-method
This page was created on June 16, 2023, and was last updated on February 25, 2026.
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