group 4 project

Group 4 Project: Group 3

Presented By: Victoria, Cindy, Pin, Ani

Introduction: Aim

The aim of this experiment was to determine how temperature affects the elasticity of rubber bands.

Rubber’s scientific name is polyisoprene, and is made of the repeating unit shown below.

Research Question

How do different temperatures, measured in degrees Celsius, affect the elasticity of rubber bands?

Materials

A pack of rubber bands Force gauge 1 tray (one that it relatively tall and long) Utility clamps or metal hooks Thermometer Hot plate Ice Beakers

Procedure

1. Place the utility clamp at the edge of the tray

2. Place a wooden stick in the clamp and tighten it so that the stick would not move

3. Add enough water to submerge the wooden stick

4. Take the temperature of water5. place rubber bands in the water and

make sure they are completely submerged

Procedure (cont.)

6. Leave rubber bands about 10 minutes in the water

7. Mark a point (A) on the stick and bind the rubber band around it and use a force gauge to pull the rubber band to point B. point B is located about 20cm above point A.

8. Record the force.9.After 10 trials using the same temperature,

change the temperature of the water.10. Either add ice to decrease the temperature,

or boil the water on the hot plate to increase the temperature.

Results of the investigationTemperature of water used (Celsius) Uncertainty:±0.5

degree Celsius

Average force of 10 trials (N) Uncertainty:±0.3

5.0 4.6

11.5 4.8

28.0 3.9

38.5 4.5

48.0 4.2

59.0 4.0

68.5 4.1

Results of the investigation (cont.)

Brief conclusion

Results for t test between highest temperature (68.5 degrees) and lowest temperature (5 degrees)

P value and statistical significance:   The two-tailed P value equals 0.0962  By conventional criteria, this difference is considered to be not quite statistically significant. 95% confidence interval of this difference: From -0.098 to 1.098

Evaluation: weaknesses/limitations

The length the rubber band was pulled may not have been the same during every trial, so the force may have been affected.

The force gauge was not always perpendicular to point A of the rubber band, so the force measured may have varied.

Evaluation: suggestions

Use a digital force gauge

Thank You : )