Reply To: How cold will it be tomorrow?

[SteveInCO]

Heat is simply the average kinetic energy of the molecules of the substance. OK, or -459F or -273C (I dropped fractions because I don’t remember them) is the temperature where the kinetic energy is zero, of course you can’t get less than that.

Because only kelvins shows a linear relationship between heat and the number on the scale, it’s preferred by physicists; many formulae have “temperature” as a variable and it needs to be absolute, just like distances, etc., are, with zero being the lowest possible value. Celsius or fahrenheit are more useful in a day to day context becuase the numbers are reasonably small for temperatures we are likely to run into in our daily lives. (Fahrenheit, in fact, was originally designed so that weather would be in the range 0-100, but of course there’s plenty of weather outside that range.)

Given that zero is in different places on all three scales, as pointed out, it’s important to know the scale when presented with a question like Unseen’s.