Science Buddies: "Ask an Expert"

Hello,
My science project will test the rebound rate of two separate tennis ball brands. I will measure the rebound rate of each ball prior to testing.

I plan to expose both tennis balls to the same conditions over the course of 1 week to include:
1) Simulated impact using a tennis ball machine
2) Exposure to heat in direct sunlight
3) Exposure to cold

Once both tennis balls have been exposed to impact and the elements to simulate play, I will remeasure rebound rate.
The ball with the least change in rebound rate will have maintained its original state the best.

Is it beneficial to use and display data collected during the week if the final rebound measurement is most directly tied to the hypothesis?

Hi zachlindsey,
I am sorry to say that I am not following / understanding the question completely. Can you help me understand this better by explaining your hypothesis please?

In very general terms more data is better but they should always be relevant to the experiment. In your case, here's an example of why you might want to display all of the data through the week: Let's say brand A have a higher rebound rate for the first 3 days of simulated play. On day 4, Brand B started having the better rebound rate and this trend continued till the end of the week. If you only had the final rebound measurement, you may not have observed this change. (which in turn will lead to another questions / scientific inquiry )

Hope this helps. Please let us know if you have any other questions.
Good Luck with your experiment!
Willey

Hi zachlindsey,

It seems to me that you are testing whether or not temperature affects rebound rate; please correct me if I am wrong. In that case, I agree with LeungWilley in that more trials are better because they will show more data points so that you can determine a trend. You might also want to have three or more tennis balls for each temperature so as to minimize the effects of variation between different tennis balls. Good luck and I hope this helps!

Sincerely,
Elena