# Connection between ppm and length?

1. Jul 26, 2004

### mjdwyer23

Hi everyone-
I'm a junior at U. Penn doing a research project on thermal expansion in complex perovskites. I'm having trouble with a computer program that I'm using to control and obtain data from our dilatometer. The problem is that the software was made in the mid to late 80's, and it only gives data in ppm. What I need to do is convert the expansion to a percent. The program, however, seems to not measure the original length at all. It looks like it tares the sensor at the programmed reference temperature and goes from there, but the alpha (thermal expansion coefficient) needs to be calculated with the original length. Is there any way I can convert from ppm to cm to get a percent change somehow? Thanks

Matt Dwyer

2. Jul 26, 2004

### Staff: Mentor

ppm = parts per million

ppm means parts per million, so you should be able to convert it to a percent: x (ppm) = $x/10^4$ (percent).

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