# What's with the weird definition for the Calorie? [duplicate]

I came across this definition for the calorie, which I found... strange:

"The (15°) calorie is the heat required to raise the temperature of one gram of water from 14.5°C to 15.5°C."

Subsequent searches on-line revealed that this was (one of) the standard definitions for the Calorie.

Now two issues came to my mind after I read that definition:

1) Why is the term 'heat' and not 'energy' used?

From what I recall from my Thermodynamics classes at school last year, heat is energy in transit. I'm under the impression 'heat' is more of a 'surface phenomenon' if you will; there's 'heat' at the junction between two surfaces, but no matter how much you 'heat' up a body it can never contain heat (strictly speaking).

2) What's so special about the 14.5°C and the 15.5°C range?

Seriously, why that particular range? Why not 0°C to 1°C, or even 1°C to 2°C? Heck even 14°C to 15°C would go down (mildly) well with me, but 14 .5 °C to 15 .5 °C? What's with the inordinate fondness for the 0.5°C? A 1°C difference is a 1°C difference in temperature, so why specify any range at all? Why not define the calorie as 'The energy required to raise the temperature of one gram of water by 1°C' ?

I didn't have this question before because I, for all practical purposes, only used to see the calorie as being roughly equal to 4.19 Joules.

Would anyone happen to have the answer to those two queries?

EDIT-

I've already seen this particular question, and I believe it is necessary to state that this does NOT answer my question. My question is distinct from it in the following respects:

1) I'm asking for a clarification regarding the use of the term 'heat' over energy.

2) I want to know why a generalization of the definition, replacing the arbitrary temperature range with a '1° difference' wouldn't suffice.

3) I want to know why the range is demarcated by two fractions (14.5° and 15.5°) instead of integers.

• – Loong Oct 9 '16 at 14:40
• hope i get the satisfactory answer here for my question(chemistry.stackexchange.com/q/60321/7951) – Vidyanshu Mishra Oct 9 '16 at 16:07
• I also use related, when it is related. You're asking about the same thing here. – Mithoron Oct 9 '16 at 16:16