Bouncy Ball Lab Report

Introduction:
The point of this lab is to analyze data and draw conclusions that will be used to base the selection of optimal combination of the reactants to create the best possibly structured bouncy ball using the materials available at hand. Borax acts as a cross-linker for the polymer molecules in the polyvinyl acetate which makes chains of molecules stay together when you pick them up [2]. The balls will then be tested for durability and quality through a series of tests thought up based on certain conditions needing to be met. Having the balls put through these varying conditions will show how optimal the choice of combination of the reactants used to make the final ball really was [4].

Materials/Methods:

Borax
Polyvinyl acetate

Cornstarch
Beaker
Water
Graduated cylinder
Thermometer
Hot plate
Ice
Watch glass

In a glass beaker 9 mL of polyvinyl acetate and 2 mL of water were mixed.

Then 4 mL of borax were added. The other ratios, being 25:5:8mL, 10:2:3mL, 6:1:2mL respectively, tested in the day prior did not stand to be quite as durable or stable and fell apart overnight. The ingredients were then allowed to interact on their own for 10-15 seconds and then stirred together to fully mix. Once the mixture became impossible to stir, it was taken out of the beaker and then started to be molded into a ball. The bounce height and elasticity of the ball under normal environmental conditions were recorded. The height was tested through means of dropping the ball from a certain height repeatedly, about 60.96 cm, and then the height the ball bounced on the first bounce was recorded through several trials and the averaged. The elasticity was then tested by gripping two opposite ends of the ball and pulling them apart slowly until torn and the length of the ball at that point was

recorded through several trials and then averaged as well. Previous steps were repeated to make two more balls for a total of three to be tested. One ball was heated on watch glass over a beaker of boiling water to simulate dry heat conditions on the ball that would be felt by the ball in New Mexico. The ball was then tested for the bounce height and elasticity. Thereafter another ball was heated held over the steam from the boiling water using wiring wrapped around the ball to simulate wet heat conditions the ball would be put through in the travels from New Mexico to Alaska. The ball was then tested for the bounce height and elasticity again. Finally the last ball was cooled by submerging it in a beaker of ice to simulate cold environmental conditions of Alaska on the ball and then test the bounce height and elasticity.

Results:
Figure 1:
*Elasticity of the balls were all found about 15 minutes after balls were held in specified condition.

Temperatures correspond to the condition of the regions the ball will be traveling through

Discussion:
The ball was tested for its durability and quality through a series of tests thought up by you to see how well your ball stands under conditions for a certain scenario, in this case travel from New Mexico to Alaska.

So the balls would therefore be tested under the weather conditions of the regions in which the balls would be transported through as closely as possible. At the start of the transport the balls would be under the conditions of the dry heat of New Mexico reaching temperatures of 46ºC in the summer which derived the dry heat test performed by putting the ball on a watch glass over a beaker of boiling water acquired and maintained using a hot plate as done in step 4 of the procedure [1]. The half way point of the transport, around Utah, would most nearly be comparative to the normal conditions of the room held at standard room temperature. Lastly, freezing weather condition aspect of the end portion of the transport is replicated with the submerging of the ball in a beaker of ice in an attempt to get as close to the Canadian-Alaskan region temperatures of the travels that the ball would be experiencing, 1ºC [1]. This being performed in the final part of the procedure, step 6. This will all show how the ratio of reactants in the selected combination really comes into play in an everyday life situation such as material or product transport across the

country.

Conclusion:
The balls, when put through the conditions of travel, did not preform, referring to bounce and stability or durability, quite that well. The results were far from impressive and did not actually even make any sense. For one, the ball held under the condition of dry heat should have that bounce height and feel comparatively to the ball under normal conditions but should not have had an elasticity the same as the normal. This is because the heat should increase the energy in the molecules giving them enough to be able to break the bonds between each other making the ball break apart which would therefore result in a farther stretch of the ball when pulled apart. Then thereafter, the wet condition should not have had that same issue but to an even further extent. The ball held under the wet heat conditions had a weaker elasticity than the normal ball when it should be just the opposite due to the increased activity of the molecules and break up of the structure in the ball. As to only make matters worse, the ball held under the simulated freezing weather condition temperatures of the Canadian-Alaskan regions of the ball transport route showed promising results for the bounce height and the feel just as the others did but with same consistent issue of the elasticity. The ball was even worse than the first two in having adverse results with the ball having a 2.54 cm longer elasticity when it should have been weaker and shorter of an elastic capacity. Being that the consistency of the proceeding issue was so precise the conclusion of the reasoning for the concerning matter at hand becomes clearer and clearer as just the expected reasoning. The reasoning being the balls’ 15 minute delayed testing of the elasticity. The delay giving the molecules of the ball plenty of time to return original temperature and reciprocal activation energy and even possibly going past that point to a further point in the opposite direction of the temperature needed. This therefore causing the balls to display similar results to that of the original ball and, if passed beyond the point of origin temperature, very antagonistic results to that of which would be expected based on previous knowledge of chemistry in the elasticity test. So in the end, with the assumption that that was in fact the syllogism to the issue, then everything falls into place and makes sense. Though with that being said, it can be concluded that the balls would not do very well in holding its structure transport across the country along that route due to the dry heat of New Mexico alone. Other than that, the normal and freezing weather conditions of the route would not pose a problem as the balls hold their structure fairly well under those tested conditions.

Research Connection:
In this experiment we brought together borax and polyvinyl acetate where the borax acts as a cross-linker for the polymer molecules in the polyvinyl acetate which makes chains of molecules stay together when you pick them up [2]. As such is happening in this experiment is also happening in the experiments of American chemist Charles Goodyear when he discovered that rubber could be made much stronger by heating it in the presence of sulfur. The sulfur acts like the borax does in this experiment by cross-linking the hydrocarbon polymer chains to form a stronger interlocking mass [3].

References:
[1] “Experiment While Making A Bouncy Ball." Science Bobs Science Experiment Blog RSS. N.p., n.d. Web. 29 Sept. 2014.

[2] “Weather.” Local 7 Day Weather Forecast, Radar, Long Range Predictions. N.p., n.d. Web. 24 Sept. 2014.

[3] Jia Lu Allan J. Easteal Neil R. Edmonds, (2011),"Crosslinkable poly(vinyl acetate) emulsions for wood adhesive", Pigment & Resin Technology, Vol. 40 Iss 3 pp. 161 - 168