# Definition of 1 calorie

Why has the definition of 1 calorie been taken to be the energy required to heat 1 gram of water from 14.5 to 15.5 degree centigrade at standard pressure? Is there any specific reason for taking the temperature from 14.5 to 15.5?

• There are several definitions of calorie. See wiki page. – Gonenc Mogol May 28 '15 at 18:30
• Are you asking why some specific range was chosen, or are you asking why the starting point of 14.5 was chosen for the specific range? – BowlOfRed May 28 '15 at 18:33
• Pretty sure he's asking why the starting point is 14.5 degrees centigrade. As far as I know, no reason. I've always learned that it was the energy required to warm 1 gram of water by $1^{\circ}C$. – CoilKid May 28 '15 at 18:50
• I suspect this belongs on hsm.stackexchange ... our sister site for "history of science and math". – Floris May 28 '15 at 19:25

• That's one nice thing about water though, the different states have their own names. In my experience, when someone says "water" it is assumed they are referring to liquid $H_2O$ unless otherwise stated. Anyway, you make some good points. +1! – CoilKid May 28 '15 at 21:43