Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Absolute Zero

  1. Dec 29, 2006 #1
    How can we say that Absolute zero is the lowest possible temperature?
    Is there any experimental evidence for it?

    Keep Smiling
  2. jcsd
  3. Dec 29, 2006 #2
    Temperature is a measure of the kinetic energy (movement) of the particles in a substance. Theoretically, absolute zero is the temperature at which everything stops moving, making it the lowest possible temperature.

    People first got the idea from looking at temperature vs. volume graphs of gasses. At constant pressure, they are directly proportional and form a straight line. Imagine a graph with a y intercept of 5 liters at 0 degrees celsius. As you decrease temperature into the negatives, the volume will decrease linearly until a certain point. What happens at the x intercept, with zero volume? The answer is the same for all gases and is called absolute zero. If you extend the line enough, you get to the lowest temperature possible
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook