Rubber Band Elasticity & Temperature

BIG QUESTION How does the elasticity of polymer (or example rubber) change with temperature? The purpose of this experiment was to determine the effect of temperature on the elasticity of a rubber band.

HYPOTHESIS My hypothesis was that if the rubber bands are stored in zero (0) degrees Celsius then it will be less elastic than the ones stored in 20 degrees Celsius or 80 degrees Celsius. I based my hypothesis on the observations and internet-sites which stated that solid materials generally expand and contract when cooled.

Interesting Facts Natural rubber was introduced to the western world by Charles de La Condomine in 1736. Rubber Band’s Elasticity, water resistance and lightness have made it a universal commodity. Close to 21 million tons of rubber band were produced in 2007. On an average most rubber bands are made out of natural rubber which performs better under extreme conditions than synthetic rubber. The holder for the world record for the largest ball made from rubber bands is John Bain of Wilmington, Delaware. He used 350,000 rubber bands.

Materials QUANTITY ITEM DESCRIPTION 75 Rubber Bands 1 each Spring Scale, Oven, Freezer, Glove

Procedures Gather all materials. Separate 3 groups with 25 rubber bands in each group. Put 1 group of 25 rubber bands in a freezer at 0 degrees Celsius temperature. Store it there for 3 hours. Take all of the rubber bands in that group out. Take 1 of the rubber bands and put it on the spring scale and pull it down. Right before it breaks read what it says on the scale. Record your data. Do this with every rubber band. Put another group of 25 rubber bands in room temperature set at 20 degrees Celsius temperature. Repeat steps 4 through 9. Put another group of 25 rubber bands in an oven at 80 degrees Celsius temperature.

Constants And Variables The Brand of rubber bands. The scale I will use. The size of the rubber bands. The amount of time the rubber bands are stored in the temperatures before testing. The oven. The freezer. The color of the rubber bands. Variables The manipulated variable was the temperature the rubber bands were stored in before the tests. The responding variable was how much force the rubber bands could take before they broke. To measure the responding variable I used a spring scale and I measured the elasticity in kilograms.

Observations The rubber froze at 20 degrees Celsius. The rubber melted a little at 80 degrees. They snapped at 0 degrees Celsius. They stretched more in hotter temperature.

DATA Temperature Trial 1 Trial 2 Trial 3 0OC 16cm 16.2cm 15.5cm 20OC

Analysis of Data Data demonstrates that the rubber bands do, in fact, stretch more when subjected to higher temperatures.

Conclusion The original purpose of this experiment was to determine if temperature affected the elasticity of a rubber band. Our hypothesis was that the rubber bands stretch more when subjected to higher temperatures. The results indicate that this hypothesis was correct and should be accepted. If I were to conduct this experiment again I would test the rubber bands in the temperature instead of storing them in it before the test. That would be a more useful experiment. Viewed in broad terms, it opens questions to how changes in temperature affect specific materials. Although the snap of a rubber band is not usually a cause of worry, the collapse of an operating bridge is. The experiment also points out the major weakness of a rubber band with increased temperature. The question now becomes: how do we build a better rubber band? 

References Sciencebuddies.org www.planetphysics.org www.lee-rubber.com