Why do we need a vacuum?
What could not be done in the atmospheric state, it comes to be able to be done by utilizing the various characteristics of the vacuum.There are countless gas molecules on the ground, which hinder various phenomena.Therefore, the molecule which had been a failure by vacuum is greatly reduced, and it becomes a space with few obstacles.
In other words, the pressure is low, the air is less than in the atmosphere.Various advantages are created by creating a state where the pressure is lower than atmospheric pressure.
As a characteristic of the vacuum
Because the pressure is lower than the atmosphere, there is a pressure difference.
Because there is little oxygen, things are hard to oxidize (no rust)… Vacuum packs and vacuum chilled can be used to maintain freshness of food and other products.
Because the heat is not deprived to the air by the fact that there are few molecules that transmit heat, the heat is hard to cool down.Thermos take advantage of this feature.The thermos has a double structure, and the vacuum between the inside and the outside makes it difficult for the heat to escape.
Because the pressure is lower than the atmosphere, the boiling point is lowered.Therefore, in the vacuum, the moisture evaporates while it is frozen, so only the dry ones remain.This is useful for the production of instant coffee and instant ramen.It is a technology called dry freezing.
Because the sound is transmitted by the vibration of the air, the sound is not heard.Because there are few molecules in the air that transmit vibrations, they can’t reach our ears through the air.
The number of gas molecules decreases and becomes insulated, making it difficult to pass electricity.
All, it is due to the small number of molecules in the air to transmit something.