The Kelvin Temperature Scale

It probably won't surprise you to learn that physical scientists don't measure temperatures in degrees Celsius. After all, the zero point of the Celsius scale was chosen as the freezing point of water; which is pretty arbitrary in the scheme of things.

Instead, a unit of temperature called the kelvin (symbol K) is used, which is almost identical to degrees Celsius, except the zero point is shifted to -273.15°C. You can convert between degrees Celsius and kelvins as follows:

T_kelvin = T_Celsius − 273.15,	where (of course):	T_kelvin ≡ temperature in K
	and	T_Celsius ≡ temperature in °C

The zero point in the kelvin scale (0K or -273.15°C), is called absolute zero. It's called that because it's actually the lowest temperature that's physically possible to obtain anywhere in the universe. There are no below zero temperatures in the kelvin scale - anything lower than 0K is impossible.

Don't believe me? Now read the next page, What is temperature?, and all will become clear.

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