How do you attempt to find the young's modulus of hair?

Question

Coursework. Thank you very much.

I mean what kind of apparatus and setup would you use? The kind available to High schoolers.

Answer 1

this is going to be hard, but you need to extend the length of hair by adding weights on it. and measure the extension, length, area of the hair and weight added.



young modulus, is equal to STRESS/STRAIN
STRESS=Force(N)/area(metre squared)
STRAIN= extension(m)/original length(m)

just set up a experiment where theres a piece of hair , and add like 1g of weight each time, then note down the extension created, like 0.0001m . then you need to set up a scatter graph of STRESS and STRAIN. then take the gradient of it. then thats your young modulus,.

Answer 2

The first answer is partially correct. The Youngs Modulus is the modulus of elasticity. The experiemental difficulty is determining howmuch of the extension (the increase in lenght due to the added load) is elastic and how much is plastic. Elastic is like a rubber band, it stretches but when you remove the load, it returns to its original length. Plastic deformation is like silly putty, once it is stretched, it does not go back to it's original length. The best way to determine E (Young's Modulus = the Elastic Modulus) is with a tensile test machine that accurately and precisely measures load and elongation. For a material like hair, the elastic modulus may be very small, i.e., it may go from elastic to plastic at a very low load, maybe less than 1 gram.