Why Must We Use Absolute Temperature for Ideal Gas Law?

[jack1234]

Question
Why must we use absolute temperature in the ideal gas law (PV = NkT)?
Why using the Celsius scale would give nonsensical results?

I am not sure what is the reason, can anyone helps?

 

[fotisz]

The temperature measured in Kelvin degrees cannot ever be negative.

 

[Dick]

At 0C the pressure in an ideal gas is not zero. It's zero at absolute zero. Which is 0K.