# Rubber Band Extension Experiment

Topics: Mass, Measurement, Eye, Force / Pages: 2 (406 words) / Published: May 24th, 2015
Extension of a Rubber Band – Experiment
Apparatus:
Retort stand (with clamp)
Spring (with hook)
Masses (50g)
Meter ruler
Setsquare
Rubber Band
Method:
1. Assemble apparatus as shown, making sure the meter ruler is absolutely vertical, and that the clamps of the retort stand are tightened enough to hold the apparatus in place.
2. Measure the initial length of the rubber band, without any masses on it to get a reading at 0g, using the setsquare (place vertically against the ruler and read off it from that), pulling the rubber band down gently to find its full length
3. Place 50g masses on the bend of the rubber band gradually, reading off the ruler after each mass is added
4. Continue until 600g of masses have been added (max mass before the rubber band snaps)
Results:

Variables:
Independant variable
Changing the mass (g) ჻ weight force (in Newtons)
Dependant variable
Extension of the rubber band (cm)
Controlled variable
Dimensions of the rubber band (length, temperature, etc...)
Height of retort stand

Conclusion:
As the weight increases, the extension increases. This will continue as the rubber band stretches, but only up into a certain point (for us it would be 600g+), when the rubber band’s elasticity becomes too weak, and the rubber band snaps. The elasticity is also not directly proportional to the force applied (so there is a positive correlation), so the line of best fit would be a curve, rather than a straight line that goes through zero, therefore Hooke’s Law does not apply.

Evaluation:
The results may not be totally accurate, as the measurements were taken off a meter ruler by the human eye to the nearest mm. By using a setsquare, we tried to eliminate the chances of incorrect readings being obtained, but there could still have been some inaccuracies due to, for example, the rubber band still bouncing when the measurements were taken.

Ways to prevent further inaccuracies:
Using a