Kalor

Kalor is a unit of energy. Historically, it was defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius. This definition led to two common versions: the small calorie (cal) and the large calorie (Cal), also known as the kilocalorie (kcal). The small calorie is equal to 4.184 joules, while the large calorie is equal to 1,000 small calories, or approximately 4,184 joules.

In scientific contexts, the joule is the standard international (SI) unit of energy and is generally preferred. However, the calorie is still widely used, particularly in nutrition, where the kilocalorie (Cal or kcal) is the common unit for measuring the energy content of food. When referring to the energy in food, the term "calorie" almost always means kilocalorie.

The concept of the calorie arose from early studies of heat and thermodynamics. Early experiments by scientists like Nicolas Clément and Pierre Antoine Favre helped establish its value. While the fundamental definition of the calorie has been refined over time with a greater understanding of physics, its practical application, especially in dietary contexts, remains significant. The transition to the joule as the primary scientific unit reflects a broader standardization of measurement across disciplines.