Lets make it simple for you to understand this concept. If your glass is empty that it means you have absolute zero of water. No water in it. You need an egg. You open the fridge, and no egg inside the fridge that it means you have absolute zero of egg. In another case, a student got zero for his/her test, this is not an absolute zero or what you call true zero, because it doesn't mean the student know nothing about the test. The score zero is just the lower score that she/he got perhaps by answering all the questions wrongly. One more example, the time 00.00 is not an absolute zero because it doesn't mean no time here, but the zero here is a recursive of the starting point of the counting of a new day

Some other examples, beyond temperature, I’ve seen given in stats books:

* pH values (acidity/alkalinity)

* time of day (e.g., 2pm-1pm = 3pm-2pm, but the ratios 2/1 & 3/2 are not meaningful)

* the rank-order place of competitors (1st place, 2nd place, …)

* IQ test scores

Temperature in classical Thermodynamics / Physical Chemistry is defined as the amount of molecular motion so measuring in Kelvin does have a meaningful zero - absolute zero with zero molecular motion.  pH does have a meaningful zero (pH = 7 for no hydrogen ions), though it’s not 0 and the scale isn’t really interval because it is logarithmic (each interval of 1 toward acidity is a 10 fold increase in acidity).

Sometimes I feel stats discussions trying to categorize variables like this create more confusion for scientists than anything they clarify.  To me, it seems if you understand the science of what you’re measuring, it’s immediately apparent what the meaning would be, if any, if you found the difference or the ratio.

Best wishes Sabri.

Kevin

Hello Sabri,

maybe I got you wrong here, but just to make sure: Temperature is such a good example for the different scales of measurement, because Celsius and Fahrenheit have interval scales, but Kelvin has in fact ratio scale (0 Kelvin is the absolute, non-arbitrary zero).

Best,

Steffen

Lets make it simple for you to understand this concept. If your glass is empty that it means you have absolute zero of water. No water in it. You need an egg. You open the fridge, and no egg inside the fridge that it means you have absolute zero of egg. In another case, a student got zero for his/her test, this is not an absolute zero or what you call true zero, because it doesn't mean the student know nothing about the test. The score zero is just the lower score that she/he got perhaps by answering all the questions wrongly. One more example, the time 00.00 is not an absolute zero because it doesn't mean no time here, but the zero here is a recursive of the starting point of the counting of a new day