Elastic bands

[helpful mum]

My son has a homework assignment to plan an experiment as to what things affect the stretching of an elastic band, I am not sure in which respect? Do you think that this would mean testing different weights etc hanging on the band?

[brachiopod]

You don't say what age he is - but the classic experiment demonstartes Hooke's law.

This states that an elastic band (or a spring) will stretch proportionally to the mass (weight) applied.

If your son hangs different weights on the band and measures the 'amount of stretch' - (ie the lenght of the band) - he should find that the heavier the weight, the longer the stretch, and if the weight doubles, the length (stretch) also doubles.

Have Google for "Hooke's Law" for some more background.

[helpful mum]

Thankyou very much for your help, I hope for a stress free weekend!

[brachiopod]

There is a proviso that states Hooke's Law applies provided the elastic limit is not exceeded.

For a spring, the elastic limit is exceeded when it stretches and becomes bent out of shape and won't return to its original shape.

For an elastic band, when the limit is reached it snaps !!

So a stress-free weekend? I think not - lots of 'laccy bands flying about the place !!! Good luck !

[dilf]

what affects a elastic band stretching could be heat ,cold ,abrasion and such like dont you think.

[bobjim1705]

On a different note, you could also test the effect temperature will have on an elastic band.

An elastic band left in the freezer overnight won't have as much stretch in it as a room temperature one.

[erimus1]

Also consider pressure - i.e. air tight and/or under water.