What are absolute, relative and arbitrary scale?

Question

I have seen the wikipedia page but still a bit confused. Can anybody elaborate it in simple laymen terms with examples.
Thanks

In: Other

Answer 1

Absolute scale means something is measured from zero, and everyone has the same reference point. Temperature is measured day to day in Celsius (if you’re in a modern country) or Fahrenheit (if you don’t).

Temperatures measured in Kelvin start at zero and can’t go below. There is no condition under which anything will get under zero kelvin and we measure everything up from there.

It can go below zero in C or F-> they are not absolute.

+1C is the same as +1K but the starting point (zero) isn’t. Celsius is temp in K minus 273.15. -> this is a relative scale.

Now the 1 scale is based on freezing and boiling point of water divided by 100. That’s arbitrary. So the zero isn’t but the steps are.

Fahrenheit is arbitrary as it’s just conveniently spread across the freezing point of water and brine (zero F), the freezing point of pure water (32F) and human body temperature at 96 (later adjusted to 98). The split between 32 and 96 is 64 steps. That was decided because it easier to mark (making half dissections 6 times). See Fahrenheit wiki page.

So this scale wasn’t based on observations or facts, just basic human convenience. And that’s as arbitrary as it can get.