# Question: Determining absolute zero with a piston

1. Oct 6, 2009

### PrinceOfDeaf

I am working on a lab report related to Ideal Gases at the moment, and I can't quite grasp how you would go about finding the temperature for absolute zero. Here's a brief synopsis of our experiment: We inserted a piston into a cylinder of water to keep the piston at a steady temperature of 23 degrees Celsius. Then, we placed known masses on top of the piston and measured the height change, thereby allowing us to determine the pressure that the gas exerts (1kg, 2kg, ..., 5kg). We repeated this experiment but now with ice in the water, and this changed the system to be at a steady 3 degrees Celsius. We graphed height vs 1/pressure for both cases and computed regression lines if that has any significance to the question at hand.

How would you go about extrapolating absolute zero from this experiment?

2. Oct 7, 2009

### Mapes

Hi PrinceofDeaf, welcome to PF. What is the ideal gas law? What quantity (hint: what product) would be zero at $T=0\,\mathrm{K}$?