Question about absolute and relative measurements?

[Theminecraftaddict555]

Doing some google searches of both terms, Is it correct that relative measurements require comparing one thing to another? For absolute measurements, is it right that it requires mathametical equations and some absolute value like measuring wattage?

 

If you have any more differences between them, please do share. 

[Dash Lambda]

Absolute scales start at some natural zero-point and go up, relative scales start at an arbitrary point and express deviation in any direction from that point.

 

For instance, the Kelvin scale starts at absolute 0, while Celsius starts at the triple point of water (well, just below it actually). Absolute 0 is a natural zero point, it's the lowest you can go. (Yes, the magnitude of the Kelvin is still determined by the triple point of water, but it still starts at a natural zero).

Length is also generally measured on an absolute scale, because no length is a natural zero point. Distance, however, is a measurement of how far one thing is from another, and so is relative.

 

Usually, a measurement in an absolute scale will be expressed in simple units, while measurements on a relative scale can be expressed as units in that scale. That's why it's either Kelvins or Degrees Celsius/Fahrenheit, not Degrees Kelvin.