1, the unit of heat is called card, abbreviated as card and abbreviated as cal, which is transliterated from English. It is defined as the heat required to raise 1 gram of water to 1 degree Celsius at 1 atmospheric pressure; It is widely used in nutrition measurement and fitness manuals, and the international standard energy unit is Joule.
Most of us associate calories with what we eat or drink, such as "This soda contains 200 calories". In fact, the calories listed on food packaging are calories, and the capital letter C is also marked, which is equivalent to the heat required to raise 1 000 grams of water from 14.5 degrees Celsius to 15.5 degrees Celsius at1atmospheric pressure, which is about equal to the internal energy of 4 186 joules.