How to choose a thermos, also called a thermos or a thermos, is an essential daily appliance for every family. However, it is often said that the thermos bottle you bought is not insulated, or the insulation time is too short.

Therefore, it is very important to pay attention to the correct selection method when buying. 1. See if the gas tail at the bottom of the bottle is complete.

If the gas tail is broken or knocked off, it is defective, because the bottle liner is two layers of glass, and there is no air in the middle. The damaged gas tail indicates that air has entered and has no heat preservation effect. 2. Tap the glass on the bottle liner with your fingers. If the sound is crisp, it is a good bottle liner without cracks.

3. Check whether the silver plating is uniform, because the silver plating avoids thermal radiation and prevents heat energy loss. 4. See if the thermos bottle is round, whether the cork is tight and whether it leaks.

People often choose hot water bottles by listening to the sound, which is unscientific. The broken outer glass bottle liner will also make a "buzzing" sound, which is the sound made by air convection in the liner.