Investigating Force and Materials

Investigating Force and Materials

For this investigation I will be testing various materials to

determine how much force is required for them to snap. Figure 1 below

shows the forces that will be acting upon the test material.

[IMAGE]

The set-up above will increase the force applied to the test material

until a crack, started in the surface in tension, propagates to cause

the material to break. To experimentally determine the level of stress

that is required to break an object, I need to be-able to exert a

force onto an object and be able to quantitatively measure and record

that force. This, I found, is not as simple as it sounds due not only

to the limited equipment available to me, but also to what I could use

practically and safely. I came up with many methods of measuring the

force exerted as well as many ways of creating that force. A summary

of the major methods and their associated problems is included below.

Method 1: Creating force using my own strength.

This has several obvious advantages including ease of use. My own

strength requires no preparation to use, is easy to store when I'm not

using it and can create a very broad range of force i.e. up to 800N.

Unfortunately for all the benefits, there are several disadvantages

that make this method untenable. The greatest concern is safety,

namely my own safety. To apply the force needed to break the objects,

I would have to lean heavily on the object. This placed me in danger

of being impaled on the device I was using to concentrated force onto

the object. As well as this, there was the problem of splinters from

the object damaging my hand or eyes.

Method 2:Measuring the force using bathroom scales.

The main advantage of this method is that a large range of forces can

be measured i.e. over 1,000N. Also, they are easy to set up and use,

difficult to break and can be stored easily ready for repeating

experiments.