Development of thermos bottle
Archaeologists found a double-layer container in the ruins of ancient Rome, which is the earliest thermos-like object found in the world.
1643, the Italians put forward the vacuum principle, which laid a theoretical foundation for the invention of thermos bottles.
188 1 year, British chemists plated a layer of silver on single-layer glass, which can reduce thermal radiation and slow down heat loss.
1892 British scientific research institutions made a double-glass container, painted the inner glass wall silver, and then evacuated the air between the double glasses, and applied for a patent. Inventor of thermos bottle: British chemist james dewar, so it is also called Dewar bottle.
1904, the Germans put a coat on the glass and blocked the bottle mouth with soft rubber or plastic to achieve better insulation effect. This is a modern thermos.
China was first made of glass and painted with mercury in the Song Dynasty. Its shape is not much different from that of a modern thermos. It has a wide mouth, a long neck and a handle. At that time, it could only be used in the palace, which was very precious. The emperor gave this thermos bottle to the princess as a dowry.
How is the thermos kept warm?
People will feel warm when they are close to the fire source. This is the heat transferred from the fire source to people. This is thermal radiation. The best way to prevent heat radiation loss is to reflect it back with a mirror.
Where a cup of boiled water is placed, the heat emitted by boiled water will be slowly absorbed by convection with air, and the boiled water will become cold. If you put a lid on the cup, the heat will not convection with the air, which will slow down the cooling time of boiling water.
The thermos bottle is made of double glass, and the glass wall is plated with silver like a mirror, which can reflect the heat flowing in the bottle back. The air between the double glazing is pumped out, forming a vacuum. Air is the medium of heat transfer, and the vacuum layer increases the difficulty of heat dissipation. Adding a cork to the bottle mouth cuts off the heat dissipation path, but the boiled bottle can't keep warm all the time and can only slow down the heat dissipation time.
A thermos bottle can not only keep warm, but also keep things with lower temperature cold. When a popsicle is put in, it can also isolate the outside hot air from entering the bottle, and the cold and hot air cannot convection, thus achieving the effect of keeping cold.