A thermos is a household appliance used to hold boiling or warm water.
The thermos was invented by the Scottish physicist and chemist Sir James Dewar (1842-1923), a Scottish chemist and physicist, in 1892 thanks to an improvement from Newton’s calorimeter barrel.
Pour a cup of boiling water, leave it in the air, and soon it will cool down. But, if you put boiling water in the hot water thermos, the temperature of boiling water can be maintained for a long time.
Hot water thermos retain heat is determined by the structural characteristics of the thermos.
Hot water thermos retain heat is determined by the structural characteristics of the thermos . The thermos is made up of two thin layers of glass, which pulls out the air between the two shells and coats one side of the thermos with a thin layer of mercury. The thermos has a mouth much smaller than its “body” . The mouth of the thermos can be closed with a soft wooden stopper. It is thanks to such a structure that the hot water thermos becomes a thermos “hot inside, cold appearance”.
When boiling water is finished, the structure of the thermos makes the heat of the water unable to be transferred by normal methods.
The ideal case is, after the thermos has cut off the three modes of heat transfer, the hot water in the thermos can hold heat forever. But in reality, the thermal insulation effect of hot water thermos is not so perfect, so the heat retention of thermos is always limited in time. Beyond that limit, the thermos will no longer hold heat.