Heat refers to the energy transferred due to temperature difference; It also refers to the energy generated by the temperature rise of 1 gram of water at 1 atmosphere 1 degree Celsius; Between objects with different temperatures, heat is always transferred from high-temperature objects to low-temperature objects.
Even in the isothermal process, the temperatures between objects are constantly slightly different, and a new balance is constantly reached through heat transfer. All life activities of human body need energy, such as synthetic reaction of substance metabolism, muscle contraction, gland secretion and so on.
Extended data
Calculation method of food calories
Generally, it can be found from the food composition table, or it can be accurately measured by calorimeter. Put the sample to be measured into the combustion chamber of calorimeter for complete combustion, and use water to absorb all the released energy. When a millilitre of water rises once at normal pressure, it needs to absorb 4. 187 joules, and record the changes of water quality and water temperature, and make corresponding conversion.
When heating 1 ml (mass 1 g), the heat of food samples is defined as 4. 1 87 joules for every increase of1degree Celsius.
(1) staple food: such as rice, porridge, noodles, etc. If 80 calories are taken as the calculation unit, the calories of 1/4 bowls of rice, half bowls of porridge or half bowls of noodles commonly used in daily life are equivalent to 80 calories.
② Meat, tofu and eggs: 37 grams of lean meat, 20 grams of fat meat, 80 calories. 125 grams of milk, two teaspoons or half a tablespoon of oil are 80 calories. It is worth noting that the calorie of 1 boiled eggs is 80 calories, but the calorie of 1 fried eggs is 120 calories.
Vegetables: 600 grams of any vegetable equals 80 calories.
④ Seafood: 100g is about 80 calories.
⑤ Fruit: 300 grams of watermelon and 2 oranges, all of which are 80 calories.
Baidu encyclopedia-food heat meter