Joules
The joule (J) is the SI unit of energy. It is named after the English physicist James Prescott Joule. It is the amount of work done when a force of one newton moves an object by one meter in the direction of the force also known as a newton-meter.
Calories
A calorie is a unit of energy often used in nutrition to quantify the energy content in food. Specifically, one calorie (cal) is defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere.
Calories (15°C,CIPM, 1950)
The calorie defined as CIPM, 1950 or the "15°C calorie" is a unit of energy that was historically used to quantify the amount of heat required to raise the temperature of one gram of water by one degree Celsius at 15°C. This definition was established by the International Committee for Weights and Measures (CIPM) in 1950.
Calories (15 °C, NBS 1939)
The 15 °C NBS 1939 calorie is the amount of energy required to raise the temperature of one gram of water by one degree Celsius, from 14.5 °C to 15.5 °C, at standard atmospheric pressure. This specific definition was established by the National Bureau of Standards (NBS) in 1939.
Calories (20°C)
A Calorie (20°C) is sometimes referred to as a small calorie or gram calorie. It is a unit of energy defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius from 19.5°C to 20.5°C.
Calories (I.T.)
The Calorie (I.T.) or International Table Calorie is defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere which is approximately 4.1868 joules.
Calories (Kilogram,I.T.)
The kilogram calorie is often referred to as the kilocalorie or Calorie with an uppercase 'C'). It is defined as the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius at one atmosphere of pressure.
Calories (Kilogram,mean)
The kilogram calorie sometimes referred to as a "large calorie" or "food calorie" is the energy required to raise the temperature of one kilogram of water by one degree Celsius at one atmosphere of pressure.
Calories (Kilogram,thermoc.)
The kilogram calorie (also known as the large calorie, food calorie, or kilocalorie) is the energy to raise the temperature of one kilogram of water by one degree Celsius at a pressure of one atmosphere. This unit is widely used in nutrition to quantify the energy content of foods.
Calories (mean)
A mean calorie is a unit of energy that was historically used to quantify the amount of energy required to raise the temperature of one gram of water by one degree Celsius, approximately equal to 4.184 joules.
Calories (nutritional)
A nutritional calorie, specifically a kilocalorie (kcal), is the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius. In nutritional contexts, the term "calorie" typically refers to a kilocalorie.
Calories (thermoc.)
A thermochemical calorie, often abbreviated as cal_th, is a unit of energy that is primarily used in the field of chemistry. It is defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere, precisely defined as 4.184 joules.