# To investigate the relationship between the extension and the force added, whether they are linked through proportionality.

Ahmad Mattar 11B                  Science Coursework (Hooke’s Law)                                        01/05/07

Aim:

To investigate the relationship between the extension and the force added, whether they are linked through proportionality.

Hypothesis:

I predict that there will be a relationship between the force and the extension.  I believe that as the force added increases so will the extension.  There should also be a pattern, which will help describe the relationship between the force and the extension.  I am led to believe this from the scientific theory of Hooke’s Law, which states that:

## “The extension is directly proportional to the stretching force”

This means that if the force is doubled the extension will be doubled or if trebled it will be also trebled and it follows this same pattern.

Fair Test:

For this experiment I will be using elastic bands rather than springs.  I will have to make sure that it is a fair test to have the most accurate results possible.  Factors, which I have to take into consideration, are things like the length and thickness of the rubber bands.  I must also make sure to use a new rubber band so it won’t be worn out or damaged as not to get wrong results.  To overcome this problem I’ll use one average sized and thickness rubber band throughout the whole experiment.  I must not put to much weight on the rubber band or it will reach its ‘elastic point’ and be permanently damaged.  For this experiment to be a fair test I will keep everything the same and only the controlled variable, the weights, will change.  To ensure to get the best possible results I will record three sets of results and find the average.

Apparatus:

• 1 metre rule
• Retort stand
• Medium sized elastic band
• Weights
• Clamp

Diagram:

Method:

1. Set up the apparatus like in the diagram
2. Measure the original length on the elastic band before putting any weights on
3. Put 50g of weight on the hook of the elastic band
4. Next measure the new length of the elastic band
5. Work out the extension (New length – Original length = extension)
6. Record ...