Because the thermos bottle is mainly used for hot water heat preservation in the family, it is also called hot water bottle. The construction of thermos is not complicated. In the middle is a double-layer glass bottle, which is vacuumed between the two layers and plated with silver or aluminum. In the vacuum state, heat convection can be avoided. The glass itself is a bad conductor of heat. The silver plated glass can reflect the heat radiated from the inside of the container back. In turn, if the cold liquid is stored in the bottle, the bottle can prevent the external heat from radiating into the bottle. The stoppers of thermos bottles are usually made of cork or plastic, both of which are not easy to conduct heat. The outer shell of the thermos bottle is made of bamboo, plastic, iron sheet, aluminum, stainless steel and other materials. The opening of the thermos bottle is provided with a rubber washer, and the bottom of the thermos bottle is provided with a bowl shaped rubber cushion seat. All these are used to fix the glass bladder to prevent collision with the outer shell. The poor Zui function of thermos bottle is around the bottleneck, where the heat is mostly circulated by means of conduction. Therefore, the bottleneck should be shortened as much as possible during manufacturing. The larger the capacity and the smaller the bottle mouth, the better the heat preservation effect. Under normal circumstances, the cold drink in the bottle can be kept at 4 within 12 hours. C or so. The boiling water is 60. C or so. Thermos bottle is closely related to people's work and life. It is used to store chemical Yao products in the laboratory, food and drink in picnic and football match, contact thermos, etc. But the principle of heat preservation remains unchanged.