Introduction For my physics coursework, I have been asked to investigate the factors which affect the way in which a squash ball will bounce. I looked into a few different factors, including; Heat of the ball, landing surface of the ball, and in depth: the height from which the ball is dropped. To observe how the height a ball is dropped from affects the height the ball bounces back to, we put a meter stick against a wall, with another one directly above it (two meters tall).
We then held the ball so the bottom of it aligned with the height we were planning to drop it from (.80 m, 1. 00 m, etc) and released it. Meanwhile, another member of our team was lying on the floor facing the meter stick, and observed, from ground level, how high the ball rebounded. We dropped the ball at . 2 m intervals between 0. 6 and 2. 0 m . We dropped the ball from the same height five times in order to account for anomalous (or ‘misfit’) results, and to keep it a fair test. One more thing we did to try and enforce a fair test was to heat the ball to 40 degrees Celsius after every five drops.
Of course, the measurements obtained in this experiment are not as precise as they perhaps could have been had we performed our research at a college, or private school, due to the fact that state-of-the-art equipment such as video cameras, and frame by frame play back facilities were unavailable to us. Heat & Elasticity Warm balls bounce higher than cold balls. I believe that this could be due to one, or both, of the following reasons: 1. The air inside the hollow, airtight ball is trapped. When air is heated the distance between the molecules increases, and therefore the amount of pressure within the airtight ball increases.
Quite how this could affect the height of the ball would require a lot more detailed research. 2. The molecules of rubber which the ball consists of may become more flexible when heated, and therefore give the ball a little extra elasticity, thus giving more Elastic Energy at stage 3ii in my diagram. Again, just how this works would require more research. Different Surfaces Balls bounce different heights off of different surfaces. I believe this is because a soft surface absorbs a lot more energy from the ball, thus giving the ball less energy to bounce back with.
In contrast, a hard surface would not absorb a lot of energy from the ball, so the ball would have more energy to bounce up. If my theory is true, a ball dropped from a fixed height (i. e. 0. 80 metres) would bounce higher from a solid surface (i. e. wood) than from a soft surface (i. e. sponge), and also the ball would bounce for a longer duration of time on a solid surface. I could not test this theory because the time was limited. Why a Squash Ball Loses Height When it Bounces Energy Transfer Diagram KEY Blue box = Potential Energy Green box = Kinetic Energy
Red arrow leading to red box = Wasted Energy 1 This is the point at which the ball is being held in the air, it has only got Gravitational Potential Energy because it is still and is being held in the air. The higher the ball is being held the higher the amount of Epg it will have at this point For example If the ball was held at 80 cm (or 0. 80 m), we would do 0. 024 (mass) 0. 239 (Gravity) 0. 80, which gives us the Gravitational Potential Energy; 0. 005 joules. 2 This is when the ball is moving through the air (because we let go of it). At this point, the ball has Kinetic Energy.