What Factors Influence the Spring Constant of a Rubber Band?

[dilpreet28]

Hey

I am doing a practical on the spring constant of a rubber band, we have studied hooke's law and from that found that the spring constant of a spring is well F = -kx so F is proportional to x. While i did the same experiment with a rubber band, hung it on a clamp connected to a retort stand, added mass and measured the length, did this for 5 different masses, did 3 trials of each mass. What i found out was that in the 2nd trials the rubber band expanded more with the same masses, with the 3rd trial even more. What would be the reasoning behind this? does the rubber band follow Hooke's law in general? and what could be the reason of it extending more and more?

Thanks

 

[humanbeing]

may be, the elasticity of the rubber bands decrease after experiment.

try to use the spring, its elasticity is hard to decrease. Because the stuctures are different, the changing of elasticity also different