1. The problem statement, all variables and given/known data So I have before me a set of springs about this size: http://tinyurl.com/8g7kvu5 [Broken]. Some are a little longer, some are wider, and some are slightly stronger. I need a home-made way to measure how much potential energy each spring can build up if I compress it at 2 inches or 3 inches (or any inch for that matter). There just has to be some sort of constant thing you can measure for each spring that tells you how "strong" it is. How would I do that? 2. Relevant equations F=kx 3. The attempt at a solution I've tried compressing each string with my thumb and index finger, but I don't quite trust my subjective evaluation. I was hoping to get something more standardized. Should I use a spring scale? Do you guys know if there's a home-made method of measuring spring potential energy?