Definition:Calorie

Definition

The calorie is a CGS unit of heat energy.

It was originally defined as equal to the energy required to raise the temperature of $1$ gram of water by $1 \cels$.

However, it is noted that this energy depends upon the initial temperature of the water itself.

Hence there are a number of different definitions for the calorie:

$4 \cels$ Calorie

The $4 \cels$ calorie is a CGS unit of heat energy.

It is defined as equal to the energy required to raise the temperature of $1$ gram of water from $3 \cdotp 5 \cels$ to $4 \cdotp 5 \cels$ at standard atmospheric pressure.

$\ds $

$\ds 1$

$4 \cels$ calorie

$\ds $

$\approx$

$\ds 4 \cdotp 204$

joules

$\ds $

$\approx$

$\ds 0 \cdotp 00398 \, 5$

British thermal units

$\ds $

$\approx$

$\ds 1 \cdotp 168 \times 10^{-6}$

kilowatt-hours

$\ds $

$\approx$

$\ds 2 \cdotp 624 \times 10^{19}$

electron volts

$15 \cels$ Calorie

The $15 \cels$ calorie is a CGS unit of heat energy.

It is defined as equal to the energy required to raise the temperature of $1$ gram of water from $14 \cdotp 5 \cels$ to $15 \cdotp 5 \cels$ at standard atmospheric pressure.

$\ds $

$\ds 1$

$15 \cels$ calorie

$\ds $

$\approx$

$\ds 4 \cdotp 1855$

joules

$\ds $

$\approx$

$\ds 3 \cdotp 087$

foot-pounds

$\ds $

$\approx$

$\ds 0 \cdotp 00396 \, 71$

British thermal units

$\ds $

$\approx$

$\ds 1 \cdotp 1626 \times 10^{-6}$

kilowatt-hours

$\ds $

$\approx$

$\ds 2 \cdotp 6124 \times 10^{19}$

electron volts

$20 \cels$ Calorie

The $20 \cels$ calorie is a CGS unit of heat energy.

It is defined as equal to the energy required to raise the temperature of $1$ gram of water from $19 \cdotp 5 \cels$ to $20 \cdotp 5 \cels$ at standard atmospheric pressure.

$\ds $

$\ds 1$

$20 \cels$ calorie

$\ds $

$\approx$

$\ds 4 \cdotp 182$

joules

$\ds $

$\approx$

$\ds 0 \cdotp 00396 \, 4$

British thermal units

$\ds $

$\approx$

$\ds 1 \cdotp 162 \times 10^{-6}$

kilowatt-hours

$\ds $

$\approx$

$\ds 2 \cdotp 610 \times 10^{19}$

electron volts

Mean Calorie

The mean calorie is a CGS unit of heat energy.

It is defined as equal to $\dfrac 1 {100}$ the energy required to raise the temperature of $1$ gram of water from $0 \cels$ to $100 \cels$ at standard atmospheric pressure.