Fun with springs - Hooke's Law

The idea for this experiment came from learning about forces in school. I wanted to make an experiment to share my new knowledge with my class.

This experiment is about seeing how much a spring will stretch if a certain amount of weight pulls from it. This is called Hooke's law, after the scientist that first proofed this concept, Robert Hooke.

Procedure

I attached a spring under a table with a hook at the end, so that I could hang different weights. I also fixed a ruler to the leg of the table to do the measurements

Then I created different weights by putting water in a bottle for specific amounts of weight. For reference 100 ml of water is 100 grams.

Next I hung the bottle and measured the amount of stretching on the spring from its original position

I made note of the measurements in my notebook and then put them on a graph

I discovered that the points formed a line. That's very interesting!

That made me think, can I use this graph to predict what will happen if I hang any weight?  

Second Experiment

So, as a second experiment I put an unknown amount of water in the bottle without measuring. I hung it and measured the stretch.

Then, with the graph I predicted the weight. Finally, I put the bottle on the scale and verified that it was correct