3. Hypothesis

Writing your Hypothesis:

“Hypothesis” can be loosely translated as “What do you expect to happen in your experiment?” It is more than an “educated guess” as it must be testable using controls and variables. The hypothesis should be stated in a cause and effect statement, using the “if/then” syntax.

Suppose your research question is: “What happens to plants if I change the types of water that I give them?” The hypothesis might be something like: “If I change the type of water given to plants to include water taken from Lake Elsinore, the tap water at my school and Arrowhead purified drinking water, then, I think that the plants that were given water from Lake Elsinore will grow faster than those given the tap water and that the plants that were given Arrowhead purified water will grow the slowest of them all.”

It is important to word your hypothesis correctly, For example, you shouldn't simply say: “lake water is better for plants.” That is because the term “better” cannot be measured. It is an opinion. You must decide on a hypothesis that can be proven in a measurable way. For example, "higher temperatures will make the seeds sprout faster because..."

Also, it is perfectly fine for your experiment to disprove your hypothesis. If something unexpected happens during your experiment, the project doesn't need to be trashed. You just discovered something new and showed that what we expect is not always what we get.

Criteria for Making a Hypothesis Statement:

• Refers to the problem/question asked in the observation/investigation

• Must be testable

• Is stated in the syntax of “if/then”

• Expresses a cause and effect relationship between the variables

  • (The effect of the changed/manipulated “independent” variable on the measured/responding “dependent” variable

Variables & Hypothesis Worksheet