Variables & Hypothesis

Your hypothesis is a guess of how things work based on your new knowledge you acquired during your background research. You are going to test this guess so make sure your hypothesis is a testable one. For instance, if your question is "does sandy soil grow carrots better than clay soil?", you want to depend on your research to tell you what clay and sandy soil are like so you can figure a good test (experiment).

When you do your test (experiment) you will need to have all conditions exactly the same except for ONE. If too many things are changing during an experiment, there is no way to evaluate what is happening with any certainty. The things that can change are called variables. So, for our example: you could have 3 containers of sandy soil and 3 containers of clay soil all six planted with carrots. The soil is your variable and all containers are treated the same as the experiment progresses. You only want one thing to change at a time. When the carrots have grown for an allotted period of time you can evaluate the carrots by measuring something -length or weight, etc.

Imagine you are wanting to know if yeast is necessary for bread to rise. You could keep all of your ingredients, mixing times, baking pans, and baking temperatures all the same except the yeast. One batch with yeast - one without yeast. Now, after your bread comes out of the oven and cools you can measure the height of your bread loaves. This height is the data you will present on your project board. Cool, huh?

To write your hypothesis you are predicting what will happen. Please ask your teacher if you need help. Or, go to http://www.sciencebuddies.org/science-fair-projects/project_hypothesis.shtml

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