Rubber Band Elasticity and Temperature

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Question/Purpose

Hypothesis

How does the elasticity of a rubber band change with temperature?

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In warm temperatures the rubber band will be more elastic than in cold temperatures.

Materials

• Graduated cylinder
• 100 g steel weight
• Rubber bands
• Thermometer
• Scissors
• Water
• Ice
• Pot or kettle
• Stovetop
• Wooden spoon
• Ruler or tape measure
• Play dough
• Bamboo skewer or popsicle stick

Procedures

• Heat a pot of water to boiling on the stovetop. With the help of an adult, carefully pour the boiling water into the graduated cylinder.
• Using the scissors, cut one rubber band so that it is a straight ribbon rather than a circle.
• Tie one end of the rubber band to the middle of the skewer, and the other end to the hook (or knob) on the steel weight.
• Gently, being careful not to burn yourself on the hot water or steam, lower the weight and rubber band into the graduated cylinder. Rest the skewer across the opening of the graduated cylinder to prevent the whole thing from falling inside. Use putty or play dough to secure the skewer to the edges of the graduated cylinder.

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• Measure the water temperature with a thermometer. With the ruler, measure the rubber band stretch length between the skewer and the weight. Record both of these measurements in a data table in your lab notebook.
• Continue to measure the water temperature and stretch length every three to five minutes until the water temperature stabilizes around room temperature.
• Once the temperature has stabilized, pour out approximately 25 mL of water from the graduated cylinder. Add 25 mL of ice water to replace it. Mix the water in the graduated cylinder well with the handle of a wooden spoon or other long implement. Measure the water temperature and rubber band stretch length. Record the measurements in your lab notebook.
• Repeat step 7 until the final water temperature is approximately the same as your ice water.
• Repeat steps 3-8 twice more. Use a new rubber band each time. Make sure the starting length of your rubber bands (once they are tied to the bamboo and weight) is approximately the same each time.

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Test

Data Tables

Hot Water

Cold Water

Chart

Chart

Chart

Conclusion

My hypothesis was accepted because the rubber band was longer in hot water (high temperature) than cold water (low temperature).

Real world connection

From this experiment one can learn that materials expand or become longer when they are in higher temperatures. Therefore when engineers design structures, they have to consider temperature so that the structures function as intended during different seasons.