Why Do Volume-Temperature Curves of Ideal Gases Intersect at Absolute Zero?

[abhinavjeet]

Why do all the volume temperature curves of an ideal gas intersect at the same point on the temperature axis ?

 

[jbriggs444]

If you decide to model a gas as a large collection of tiny balls in a large otherwise empty space then, as you reduce the ball size toward zero you get the behavior of an ideal gas.

If you decide to model temperature as the average kinetic energy per ball in such an arrangement then you get the Charles law. The zero point on the temperature scale is the point where the average kinetic energy per ball is zero.

Neither model is exactly correct for real gasses. But they are good approximations for many purposes.