Experiment to investigate the relationship between the force applied to a spring and how much it stretches
Hypothesis: I think that the force required to stretch a spring will be proportional to the amount by which it stretches.
1) Set up a clamp and stand and G-clamp it to the table so that it does not fall off. Place a bucket with a sponge in underneath so that the masses do not fall on anyone's toes.
2)Hang a spring off the top of the clamp and clamp a ruler next to the spring. Make a mark of the origional length of the spring and move the zero mark of the ruler to it.
3) Add masses to the spring, 100g at a time up to 1Kg, and record the extension of the spring.
4) Repeat with a similar spring
At first the graph is a straight line that passes through the origin. This shows that the extension is proportional to the force applied to the spring. In this region, labelled on the graph as the Hooke's law region, F=kx, as expected. However, after this region, it becomes easier to stretch the spring but the spring becomes permanently deformed.
We used similar springs for the repeats as the original spring was deformed. It would be more reliable to use the same spring but we would have to ensure that it was well within the elastic limit.
It was difficult to read off the ruler accurately. To improve this we could use another ruler, placed at right angles to the spring and the ruler to ensure a better measurement, or we would put a magnifying lens in front of the metre rule to read the scale more accurately.