FACTORS AFFECTING BOUNCINESS OF A PING PONG BALL
Free essay example:
Aim: Factors Affecting Bounciness of a Ping Pong Ball
Hypothesis:
Background Information
The Law of Conservation of Energy states that energy cannot be created or destroyed, but can change its form. The law of reflection states that the angle of incidence is always equal to the angle of reflection
The ball, released from a certain point will gain energy and fall down at the speed of 9.81ms (the acceleration due to gravity), the ball will then hit the surface and will theoretically bounce back up. Some of the energy gained by the ball will be dispersed to the surface and the ball should bounce at a lower height than the original bounce. Now different surface have different state of hardness and texture. The harder the surface, the less energy will be lost by the ball and he higher it will bounce. Now, the smoother the surface the less energy will be dissipated through the surface (see laws of reflection), and the higher the ball will bounce.
The coefficient of restitution is a measure of the elasticity of the collision between ball and floor. Elasticity is a measure of how much bounce there is, or in other words, how much of the kinetic energy of the colliding objects before the collision remains as kinetic energy of the objects after the collision. This coefficient is different for each surface. The formulae is :
c = coefficient of restitution (dimensionless)
h = bounce height
H = drop height
Variables:
- Independent Variable: rigidity and elasticity of the surface on which the ball bounces
- Dependant Variables: the bounciness of the ping-pong ball
- Controlled Variable:
- the elasticity of the ball
- the acceleration of gravity
- the force applied to it
- the height from which it is dropped
Apparatus:
- Video Camera
- Metre Rule
- Ping Pong Ball
- Thermometer & Thermocouple
- Clamp
- Retort Stand
- A sand bucket
- An A1 sheet of paper
- A plank of wood (thin plank)
- A bucket containing earth
- A rock or marble slab (very thin)
- A thin piece of plastic
Diagram:
Procedure:
- Simmer sand on the floor, smooth it evenly out.
- Place the clamp on the retort stand.
- Clamp the ball (this prevents us from applying any force on the ball
- Start the video camera, release the clamp
- Watch and count how many times the ball bounces on this particular surface and what is the height it bounces to.
- Repeat the experiment using the other different surface (for the earth experiment simmer some earth on the floor and smooth it evenly out)
The same ball for each experiment and the ball must be placed at the same height form the ground. A thermometer must be used to measure the room temperature, if any drastic change occurs, the experiment must be stopped and started again. Lastly, a thermocouple must be used to measure the temperature of the ping-pong ball, if the balls temperature changes while the experiment is conducted, the experiment must be restarted again.
Table:
Surface Used | Height of Bounce | |||
1st Try | 2nd Try | 3rd Try | Average Height | |
Sand | ||||
Paper | ||||
Wood | ||||
Earth | ||||
Rock/marble | ||||
Plastic | ||||
Links Used:
http://www.cartage.org.lb/en/themes/Sciences/Chemistry/Generalchemistry/Energy/LawofConservation/LawofConservation.htm
http://www.racquetresearch.com/coeffici.htm
Yuvraj Dwarka Page
This student written piece of work is one of many that can be found in our International Baccalaureate Physics section.
