Energy
Energy balance is the homeostasis of energy in living systems. It is measured with the following equation:
Energy intake = internal heat produced + external work + storage.
When calculating energy balances in the body, energy is often measured in calories, with the definitions of a calorie falling into two classes:
- The small calorie or gram calorie (symbol: cal) approximates the energy needed to increase the temperature of 1 gram of water by 1 °C. This is about 4.2 joules.
- The large calorie, kilogram calorie, dietary calorie or food calorie (symbol: Cal) approximates the energy needed to increase the temperature of 1 kilogram of water by 1 °C. This is exactly 1,000 small calories or about 4.2 kilojoules.
Read more about this topic: Human Homeostasis
Famous quotes containing the word energy:
“Since the beginning of time, three-quarters of the mental energy and of the lies inspired by vanity have been expended for their inferiors by people who are only abased by such expenditure. And Swann, who was easygoing and unaffected with a duchess, trembled at the thought of being scorned and put on airs when he was with a housemaid.”
—Marcel Proust (1871–1922)
“I say, stamping the words with emphasis,
Drink from here energy and only energy,”
—Stephen Spender (1909–1995)
“Parents find many different ways to work their way through the assertiveness of their two-year-olds, but seeing that assertiveness as positive energy being directed toward growth as a competent individual may open up some new possibilities.”
—Fred Rogers (20th century)