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Backround Information

Procedure
Data Table
Graph
Diagram

Works Cited

Background Information:

Ping pong balls are composed of a celluloid material, while not a true plastic it is formed by a mixture of camphor along with nitrocellulose (“Celluloid”). Hollow within, ping pong balls may have varying internal air pressures. Ping balls have a coefficient of restitution varying from 0.89 to 0.92 (ITTF).

Coefficient of restitution refers to the proportion of an object’s velocity prior and after an impact — primarily utilized in quantifying the “bounceability” or elasticity of an object. (McGinnis, Peter).

Statement of The Problem (And Variables):

The intent of this investigation is to determine the effect temperature has upon the bounce height of a ping pong ball.  As such one would be able to graphically represent this function and potentially determine an optimal temperature value for the most superior bounce height.

Statement of The Hypothesis:

Should the temperature of a ping pong ball with a coefficient of restitution of 0.82 alter, then the bounce height will positively proportional to the temperature such that an increase of heat will cause for a greater bounce height, for the increase of kinetic energy will allow the ping pong ball to become more elastic. This is hypothesised to be true until the point of “ping-pong-ball-instability”, where the ball approaches a temperature that is too severe for it to retain its solid physical state.

Method

Design Of Experiment:

The experiment is intended to determine the effect of temperature against ping pong ball bounce height. As such, multiple ping pong balls of the identical manufacturer (and with a constant coefficient of restitution) will be utilized. Logger Pro software shall be implemented for the purposes of reducing and perhaps negating human error.

Experimental Apparatus:

• Three ping pong balls with a coefficient of restitution of 0.82
• Two 500 mL beakers
• One hot plate
• Two Thermometers
• Computer (preferably non-OS X) that is capable of bootstrapping into an unix-like OS and running Logger Pro software without consuming any amount greater than 75% of CPU cycles.
• 500 mL of distilled water
• Freezer
• A camera with tripod that is able to record video as well as export it to the previously noted ‘Computer’.
• 1 Meter Stick
• Safety gloves that may withstand extreme temperatures (up to 100o C)
• Tongs
• Wet towel

Procedure:

1. Gather experimental apparatus
2. Pour 400 mL of water into each beaker
3. Plug hotplate into power outlet and place beaker onto the middle of the plate
4. Place a thermometer and ping pong ball into the beaker
5. Soak the unused ping pong ball in the remaining 100 mL of water and place into freezer to be frozen
6. Await until the ping pong balls are in boiling water and frozen respectively
7. While step #6 is not yet complete, collect meter stick, camera, and ping pong ball
8. Position camera on tripod in recording mode 1 meter above the ground
9. Position meter stick perpendicular to the ground, and place the ping pong ball on top of it
10.  Drop the ping pong ball while the camera records
11.  Upon the second bounce pause the camera
12.  Repeat steps 8 - 11 until 5 video recordings have been saved
13.  By this time the untested ping pong balls will be frozen and in boiling water respectively.
14.  Equip safety gloves
15.  Remove beaker from hotplate and place onto wet towel
16.  Use tongs to to remove ping pong ball from beaker precociously
17.  Place ping pong ball aside and turn off hotplate
18.  Remove gloves
19.  Collect the now hot ping pong ball and return to lab area
20.  Perform steps 8 - 11 with new ping pong ball until 5 video recordings have been saved
21.  Upon completing the 5 trials, collect the now frozen ping pong ball from freezer
22.  Return to lab area and perform steps 8 - 11 with the frozen ping pong ball until 5 video recordings have been saved
23. Await until hotplate water beaker is at 80, 60, and 40oC and repeat steps 8 - 11 respectively per temperature.
24.  Perform analysis on each recorded video with Logger Pro to determine the bounce height of each ping pong ball
25.  Record data in a data table
26.  Clean lab area and return experimental apparatus to their respective locations

Conclusion

General Conclusion:

As a result of experimentation, one has come to conclude that the hypothesized notion is in fact incorrect. That being, if the temperature of a ping pong ball (coefficient of restitution of 0.82) alter, then the bounce height will be positively proportional to the temperature where an increase of heat will allow for a greater bounce height, as the increase of kinetic energy will allow the ping pong ball to become more elastic. Observing the graph, one notices that there is in fact a linear proportion of temperature against bounce height, however, the relation is negative unlike that which had been proposed in the hypothesis. The coefficient of correlation is 0.82 suggesting a relatively accurate linear relationship. One might notice that the temperature of 20°C has the greatest bounce height average of the other temperatures. This is believed to be a result of engineering optimization as the purpose of the ping pong balls is to be utilized in the game of table tennis within indoor environments. With this notion in mind, and the graph results, it is now understood that there is in fact a negative correlation involving temperature against ping pong ball bounce height, and that the outlying average at 20°C is explained by the optimization of ping pong balls; from this one concludes that bounce height of a ping pong ball is not only determined by kinematics, though material physics as well.

Evaluating Procedures

Various procedural errors exist within the experiment. A prominent instance being that of assumed ping pong ball temperature. To elaborate, it is assumed that the ping pong balls were the same temperature as the medium they had been placed in, where in reality, they weren’t exactly that temperature. According to Newton’s Law of Cooling, the contact of ping pong ball against their cooling or heating medium would cause for a rapid heat exchange that gradually slows as a function of time. As such, the ping pong balls approached the temperature of their respective mediums, though never matched precisely.

Improving The Investigation

Various errors exist in the experiment such as that of instrumental. For instance, temperature had been measured utilizing a thermometer. This results in a standard uncertainty of ± 0.5 °C. Should a digital thermometer been used, the uncertainty would be reduced tenfold, and even furthermore had an accurate probe been utilized.

To further improve the results, it would be more ideal to have conducted the experiment within an environment that is standardized (with standard pressure and room temperature). The state of the conducted experiment involved a room at 20.1°C ± 0.5°C

in a 760 torr environment.

Ultimately, these errors do not severely impact the produced results, though would reduce uncertainty and negate errors if resolved.

Works Cited:

"Celluloid." MetaFilter. Meta Filter Network, 12 Dec. 2013. Web. 14 Jan. 2015.

"ITTF Technical Leaflet T1: The Table" (PDF). ITTF. May 2013.

McGinnis, Peter M. (2005). Biomechanics of sport and exercise Biomechanics of sport and exercise (2nd ed.). Champaign, IL