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 Science Fair Coach What do science fair judges look out for? ScienceHound Science Fair Projects for students of all ages
 1 The Science Fair   2 Scientific Method    3 The Experiment    4 Recording & Analyzing Your Science Project    5 Displaying Your Project   Introduction    6 Judging   ...More

Lesson 3 The Experiment

Now that you've chosen your question and proposed a hypothesis, the scientific method now requires you to perform experiments to test that hypothesis. If the experiments show that your hypothesis is correct, it then becomes scientific theory. If the experiments do not prove your hypothesis, then your hypothesis must be rejected or modified.

An interesting example that you may already know about:- in the field of astronomy, scientists previously believed that the planets in our galaxy used to circle the earth. Subsequently, through the scientific method, it was actually shown that the planets actually orbit in concentric circles around the sun. Later, this theory was further modified, as the planets' respective orbits were found to be elliptical, and not circular.

 How to perform your experiment Variables are things (or factors) that have an effect on your experiment. There are three kinds of variables that you need to use in your experiment. They are known as independent, dependent, and control variables. The independent variable This is the variable that changes throughout the experiment. You will change this variable intentionally in order to see how it affects the other variable known as the dependent variable. In our sample experiment, the price of the hamburger meat is the independent variable that would be changed by introducing different meat of different prices. The dependent variable The dependent variable changes in response to the independent variable. In our example, the level of greasiness of the hamburger would be the dependent variable, as it would change depending on the price of the hamburger meat. The control variables The variables that are not changed are called control variables. In the example above, the independent variable is the price of hamburger meat, and the dependent variable is the level of greasiness. In a control, all variables are identical to the original experiment, except for the independent variable. The variables that are identical in both the original experiment and the control are called the control variables.
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