Elastic Band Investigation.

Elastic Band Investigation

The things that might affect this are:

• Downward force applied to the elastic band
• Length of elastic band
• Thickness of band
• Band material

My prediction for this experiment is that I think that the more force you exert on the elastic band then the longer its length will be. This is because extension is proportional to load and so if the load increases so does the extension and so does the stretching distance. Shown on a graph, I think it will look like this:

This shows that as the force (f) gets bigger, then the extension (x) will also get bigger. Higher values represent stronger, less stretchy bands, and lower values represent weaker, easier to stretch bands.

I have done some research and found that this experiment is based on ‘Hooke’s Law’

Hooke’s law is when you stretch or compress an object and they change shape, for some elastic materials a steady change in force produces a steady change in shape. Another way of saying this is that if you apply a force to a spring, the spring will stretch by some length. Double the force, double the stretch, and so on. This is known as a mathematically direct relationship. A graph showing this is similar to the one above. On a graph, since it has a direct relationship, a line is the best representation. A direct relationship can be represented by the generic formula:

y = mx + b

where m is the slope and b is the y-intercept.

More specifically:

y = mx + b                                F = Force in Newtons

k = Spring constant

Zero                        x = Extension in Meters

F = kx

Here, k is called the spring constant. It is measured in units of N/m.

Hooke’s law applies to both stretchable and compressible springs (and of course elastic bands!).

There is only one limitation to Hooke’s law, and that’s if you stretch the spring beyond it elastic limit. ...