Science Buddies: "Ask an Expert"

Hi,

So I was wondering if I should use different types of balls and then see that if temperature will affect the same way if the balls is bigger or smaller
Also how many balls should I use? If I have the grouped into three categories: Heated balls, Frozen balls, and just regular temperature. What if I do use multiple types of balls


Thanks

You can certainly learn a lot about the properties of various materials with an experiment like this.

You have the right idea about investigating different sizes and types of balls. Science is all about investigating.

First, you'll need a good way to measure the rebound of the balls. It needs to be a method that is easy to use and give repeatable results. You should pick just one ball, at one temperature and drop it many times - like 20 - so that you can understand how good your measurement technique is.

Then you can move on to different size balls, made of different materials, and constructed differently. Some balls are hollow, filled with air. Some are solid. Some solid balls are all of one material, while others have "cores" of different materials.

If you want to understand if size has an effect on the rebound characteristics, you will have to find balls of different size that are constructed in exactly the same way, using the same materials. Otherwise, you will be testing variables other than just the size.

However you decide to proceed with your experiment, multiple measurements are a must. With each ball you select, at each temperature, you need to collect data at a minimum 3 times. It's best if you can collect 5 data sample for each test point.

When you heat or freeze the balls, be sure all the different balls you test are at the same temperature. That is, all the "frozen" balls but be at the same low temperature and all the"heated" balls must be at the same high temperature. You must measure the temperature of each ball each time you drop it to measure it's rebound, just to verify the temperatures remain constant. You should be able to ensure all the balls of a given temperature are at that temperature by leaving all your test samples in the freezer or oven at the same time for a period of at least an hour. If you can get access to one of those inexpensive infrared heat guns that are available at home stores, you could easily measure the temperature of each ball every time you drop it.

After you collect all these data, then you need to plot them so you can understand how the data vary from one test to the next and from one set of test conditions to the next.

I hope this helps.

Have fun with this project!!!

Hi I was wondering why heat makes rubber balls bounce higher than balls that are at a colder temperature?


Thank you

Hi cleocurtis,

In response to your question, i want to bring up a couple of concepts, such as elasticity and thermal expansion. Do the balls become more elastic as the temperature increases? Given your results, I would think so! In that case, why? You can approach this question with a viewpoint concerning the particles in the rubber bands and the force acting on the bands. What ideas can you come up with?