# How do you measure how strong a spring is?

1. Oct 24, 2012

### KnightOfGlass

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?

Last edited by a moderator: May 6, 2017
2. Oct 24, 2012

### SHISHKABOB

so you're trying to measure the Spring Constant for each spring?

3. Oct 24, 2012

### HallsofIvy

Staff Emeritus
Hang the spring from a hook and measure its length, $x_1$. Add a weight to the end of the spring and measure the length, $x_2$, of the spring with the weight. The spring constant, k, is $x_2- x_1$ divided by the weight.

And then the potential energy, when the spring is compressed a distance x, is $(1/2)kx^2$.

4. Oct 24, 2012

### KnightOfGlass

^suppose I'm able to get the K constant, and thus the Force/Inch-of-compression for that spring. Is there a way I can plug into some equation and get how much potential energy is built up in the spring? My main goal is that I was hoping I could get some ideas for how to practically do this at home.

5. Oct 24, 2012

### SHISHKABOB

the method that HallsofIvy described should be practical to do at home

you just need a ruler and something with known mass or a scale