Hysteresis of Rubber Bands

 

I got this idea from Richard Walding’s Senior Physics page, and it is absolutely amazing. Here is what he said about it:

Hysteresis and rubber bands
When you stretch a rubber band and then let it go, you can notice that the band does not behave like a spring. A rubber band, made of latex and rubber, does not return to its exact original shape after being stretched. This is an example of a phenomenon called hysteresis. Small vehicle suspensions using rubber (or other elastomers) can achieve the dual function of springing and damping because rubber, unlike metal springs, has pronounced hysteresis and does not return all the absorbed compression energy on the rebound. Mountain bikes have frequently made use of elastomer suspension, as did the original Mini car. By studying the relationship between the rubber band during stretching and unstretching as weights are added or removed, you can determine the amount of work done on the rubber band, the amount of energy (in joules) lost by the band and plot a hysteresis curve. Of course, you’d need more than one rubber band.

As I had a burette stand, a clamp, and a weight set available, I set up the clamp so it was holding a ruler vertical. I could then place the rubber band on the end of the clamp, and measure its length with the ruler, then add a 50 g weight and record the length. This made it extremely easy to do multiple tests. Some of my results are shown below.

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The hysteresis also changed each time the thin rubber band was stretched, as the graph below shows. A fascinating subject to investigate, and it’s easy to do as well.

rubber-band-hysteresis-6

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