When boiling water is poured into a thermos, the reason for the sound is that an echo is formed in the thermos, because the thermos is relatively dense and the space is relatively small, and it is easy to form an echo.
Basic information
The thermos container is made of double-layer glass, and both layers of glass are silver-plated, which can reflect heat rays back like a mirror, thus cutting off the path of heat radiation. The vacuum between two layers of glass in a thermos bottle destroys the conditions of convection and conduction. The thermos bottle cap is made of cork, which is not easy to transfer heat, thus blocking the passage of convective heat transfer.
If the three paths of heat transfer are completely blocked, heat can be preserved for a long time. However, the insulation of thermos is not so ideal, and some heat can still escape, so the insulation time of thermos is limited.
The function of a thermos bottle is to keep the temperature of hot water in the bottle and cut off the heat exchange inside and outside the bottle, so that the "heat" inside the bottle can't get out and the cold outside the bottle can't get in. If you put the popsicle in a thermos, the heat from outside will not easily run into the bottle, and the popsicle will not easily melt. Therefore, it is scientific to call the thermos bottle a thermos bottle, because it can keep warm and cold.