Salters Hornes CWK Young Modulus of a scooby

My cwk is investigating the youngs modulus of a scooby. A scooby is a hollow plastic string like thing. My experiment used the pulley clamped to the bench method and attaching weights.

I have my results and have worked out the change in area for each load and have a graph of stesslog10 vs strain.

I'm a bit lost as to what to do next though (I've lost my cwk guide thing). I'm a bit stuck on what error bars i should do, i thought I could have made an error of 0.005m on measuring the extension and so on the x axis of my graph an error bar of +-0.005. But what for stress?

What do i need to conclude? How do I tell if my sample obeyed hookes law?

And then do i evaluate my method? I read in this thread Morbo's suggestion for a more accurate experiment, but I don't quite understand the reasoning for it (something about temperature change) or how exactly its done

Reply 1

electromagnetic

P.S

If anyone knows of any websites with cwk guides or tips or anything that would be much appreciated.

Thanks

Reply 2

Zen90

I'm doing Salters Horners c/w too, we got to find 2 parts of physics at the Bradford Museum we went, a few weeks ago and I cant find much advice on the net either. The best thing to do is ask your teacher because nobody does the same c/w for salters (at least I dont think so)