What Is the Scientific Method?
How do bees fly? Why does water freeze in cold temperatures? How does the wind blow? Our world is full of lots of curious events, and science aims to figure out why these events happen. To do this, we use the scientific method.
Scientists want to develop good explanations for the events we see in the world, and they do this by following a specific way of working. They propose hypotheses (an initial explanation), make predictions, and plan experiments. You can think of the scientific method as a process that aims to produce reliable results to answer a specific question. There are six distinct steps to the scientific method:
1. Make an Observation and Ask Questions
This is the initial step where you observe something in your surroundings and ask a question like how, why, or when.
In this step, you conduct background research on your observation or question. There are a few reasons to do this. Firstly, it stops you from making the same mistakes others have made in the past. Secondly, it helps you refine your question, and thirdly, it enables you to figure out the best way to do your experiments. When researching, it’s essential to focus on reputable sources like scientific journals or reputable websites.
3. Construct a Hypothesis
A hypothesis is an educated guess you make in an attempt to answer your question. Usually, we write hypotheses in terms of cause and effect. For example, you might say
If I do this, then this will happen.
Let’s pretend that you’re trying to work out which type of fertilizer will make your tomato plant grow the fastest. This is a biology experiment!
Observation and question: Some tomato plants grow faster than others, and they are all planted with different fertilizers. Do some fertilizers work better than others?
Research: Fertilizers with X chemical composition work the best for tomato plants.
Hypothesis: Plants grown with fertilizer B will grow the fastest.
Your hypothesis doesn’t always have to describe a change; you can also have something called a null hypothesis. This is where you expect no difference in outcome when you change a variable. For example, if your question is “are 15-year-olds better at math than 35-year-olds?” then your null hypothesis would be “There is no difference in mathematical ability between 15-year-olds and 35-year-olds”.
You don’t always have to believe a null hypothesis to use it in the scientific method, either. You could just as easily have a null hypothesis that says “the earth is flat”. The goal of a null hypothesis is to determine if there is a correlation between the variables and whether you can reject the idea that there isn’t. Sometimes rejecting an incorrect idea is the best first step for finding the truth.
For example, if we consider our fertilized tomatoes example, we could start with a null hypothesis that fertilizer does not affect tomato growth speed. If our hypothesis is proven wrong, then we can start testing individual fertilizers under a new hypothesis. This is often a good idea because it ensures that it’s worth trying different fertilizers in the first place – it eliminates the possibility that another factor is responsible for fast tomato growth.
4. Test Your Hypothesis By Doing an Experiment
In this step, you test whether your prediction is accurate (your hypothesis is supported by evidence). There are several things you need to consider when conducting experiments. For example, you need to ensure that you’re only changing one factor while keeping all other conditions the same. With the tomatoes, you should only change the fertilizer. If you changed other things, like placing some of the plants outside and some indoors or watered some with tap water and others with a sugar-water solution, you can’t be sure that the fertilizer is responsible for the change.
You must also choose the right tools for your experiment. For example, whether you need test tubes, boiling tubes, beakers, flasks, and so on. You also need to choose which apparatus you will use for measurements. If you measure temperature, then you might select a thermometer. For mass, you might use a digital balance. If you measure the volume of gas, you might use a gas syringe. And lastly, you need to keep all of your measurement units consistent (if you start with cm, then don’t switch to inches).
5. Analyze Your Data and Form a Conclusion
In this step, you collect all of your measurements and analyze them to see whether the results support your hypothesis. In this stage, you might write detailed reports, produce graphs of your data, and draw conclusions about what you see. If your measured results don’t match your hypothesis, then it’s time to go back to step one and think of a new question and hypothesis.
6. Share Your Results
In this step, you share your result with the world! Other scientists can look over your data and method and repeat it themselves or develop new hypotheses to test. Science thrives precisely because we all share our results and add to the world’s collective knowledge bank.