Science Buddies: "Ask an Expert"

hi i'm doing an experiment to investigate the relationship between how far a table-tennis ball will travel and elastic potential energy. Can you plz help me come up with a hypothesis if the Independent variable is the elastic potential energy, the dependent variable is the distance travelled by the ball and the controlled variable would be the surface it travels on. It would be great if you helped..thanks

Hi colddevil,

It looks like you've correctly identified your independent and dependent variables. The surface the ball travels on is definitely one variable you will want to control. But, there are other variables that will need controlled as well. For example, you will need to use the same type of spring for all of your tests.

Hypotheses are usually "if . . . then . . ." statements that relate changes in independent and dependent variables. In this case, your hypothesis might look like this:

"If I _____________ the elastic potential energy, then the distance the ball travels will _____________."

In the first blank, write how you will be changing the elastic potential energy (e.g., increase or decrease). In the second blank, write how the dependent variable (distance traveled) will change in response (e.g., distance traveled will increase or decrease). Try writing a hypothesis based on what you think will happen. Post back with your hypothesis, and we can give you feedback on it.

Be sure to check out Science Buddies' page about developing hypotheses (https://www.sciencebuddies.org/science- ... esis.shtml) for more information.