The Scientific Method and Experiments

The Scientific Method and Experiments


This lesson will introduce the scientific method and explain how to use the scientific method to gather data and help set up an experiment.

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The Scientific Method

Source: Created by Amanda Soderlind

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Welcome to this lesson on the scientific method. Today we will be discussing the steps to the scientific method and explaining how the scientific method is used. So first of all, I want to explain a little bit more about what the scientific method is and why and how scientists can use it.

So the scientific method is basically a set of guidelines that scientists can use in order to help explain a phenomenon. So today we're going to discuss the seven steps of the scientific method. Now as I mentioned, it's a set of guidelines, so this might vary a little bit. If you're looking in one textbook versus another textbook, the steps might vary slightly. But that's because it's just a set of guidelines. The scientific method isn't a rigid set of steps that need to be followed.

So it varies a little bit. But it's just a set of guidelines that scientists can follow to help explain a phenomenon. So even though it might vary a little bit, the general outline of the steps that you follow is generally the same depending on where you're looking. So we're going to discuss what these seven steps to the scientific method are, and then give you a concrete example of how they could be used in the real world.

So the first step in the scientific method is to make an observation. And an observation can be something that you see, that you hear, that you experience. So an observation is using your senses in order to take in information about your surroundings. So let's give you an example of this. An observation could be that a soda company has consumers who report nausea after drinking their soda. That might be an observation that they have.

The second step to the scientific method, then, is to ask a question. So you're asking a question about what you have observed. So the question then related to our example could be, is this soda causing this problem? Is it actually the soda that's causing the problem? Or could it be something else?

The third step then is to develop a hypothesis. So a hypothesis is a proposed explanation about what you think is happening. And one important thing is that a hypothesis should always be testable. You should be able to test your hypothesis.

So if we're using the soda company as an example, our hypothesis might be the soda can cause upset stomach and nausea. So that's something that we can test. We can test if the soda is causing an upset stomach and nausea. So you want to make sure that your hypothesis is kind of explaining what you think is happening, and it's also testable.

Number four then is to make a prediction. So a prediction is the first step to testing your hypothesis. You're basically asking yourself the question, what do you think I will observe? So our prediction then with our example might be, the soda is likely to produce digestive upsets.

We are predicting what we think we are going to observe if we were to set up an experiment. So we think we will observe that the soda is going to produce digestive upsets. That is our prediction.

The next step then is to test our prediction. And we test our prediction with an experiment. So an experiment is a test that's done under controlled conditions in which you can manipulate things in order to try to explain this phenomenon that's happening, try and figure out what is going on. So in our experiment, we'll set up an experiment and then we'll collect data.

So if we were to set up an experiment for our soda company example, the experiment would be maybe to hire a large amount of people to test. So maybe half of those people-- let's say we hire 200 people. And the larger the number, the better, because you would be able to collect more data. And the more data that you have, the more accurate of a test that you have.

But let's say for this example we're hiring 200 people. And we'll say half of them, so 100 of them, are given one can of soda a day for six weeks. So they're given the company's brand of soda.

And the other half of them, the other 100 of them, are given a different brand of soda. So they'll be our control group. And they're given that soda one can a day for six weeks as well. And all participants in this experiment we'll say are required to record their results each day. If they get any sort of digestive upsets, they need to make record of that.

So in an experiment we will always have variables. And variables are factors that can change. So our variable in this experiment is going to be the type of soda that we're using. We have our control group using a different brand of soda, a control brand of soda. And then we have our other group that's using the brand of soda that people are claiming makes them sick. So we're able to compare one group to the other to see if it's actually the soda causing the sickness, or if possibly it's something else.

Our next step then is to repeat our test or to make new tests. So if our results are in line with our hypothesis, we will repeat our test. So we want to make sure that we repeat several times, because as I mentioned before, the more you repeat it and the more data that you have, the more accurate your results will be. So you should always repeat your test to make sure that the results you get are not just a fluke, to make sure they're actually accurate. So the more data, the better.

Now, maybe our results that we get are different from what we were expecting. So we can either repeat it again to make sure. We can make new tests to try and test a different variable to try and figure out what's going on to help explain that phenomenon that's happening.

And then our last step is always to analyze and report. So we're going to analyze our results, and then report those results. And generally scientists will report their results in a scientific journal.

So a scientific theory is an explanation to events based on repeated tests. So scientific theories oftentimes will use the scientific method in order to explain a phenomenon. But they will have to do this several times. So they're repeating their tests over and over and over and over again and getting the same results every time so that we know when we call something a scientific theory, we basically believe it to be true because it's been tested so many times and we're getting the same results every time.

So an example of a scientific theory would be the theory of natural selection. So Darwin came up with a theory of natural selection. And it's not something that he just came up with in one day. It was something that he tested in research over and over and over again, so many times that we can actually believe it to be true.

So this lesson has been an overview on the scientific method.

  • Scientific Method

    A series of steps scientists can use as a guideline to solve a problem or examine a phenomenon.

  • Experiment

    A test set up to explain a phenomenon.

  • Scientific Theory

    An explanation of an observation that has been rigorously tested.

  • Variable

    A factor in an experiment that can be changed or manipulated.

  • Hypothesis

    An educated guess or explanation of a phenomenon.