Open the refrigerator in summer, and there is white fog in the freezer. What is this?

This layer of white fog from the freezer of the refrigerator is small water droplets formed by condensation of air outside the refrigerator.

This is a common physical phenomenon of condensation. When the refrigerator door is opened, the low temperature in the refrigerator will drift outside the refrigerator, which will make the water vapor in the surrounding air quickly cool and liquefy, forming many tiny water droplets, thus forming "white fog". Especially when the weather is hot in summer, it is easy to see this phenomenon.

When water vapor condenses in the air, it must be like a condensation nucleus composed of dust or charged particles, otherwise it will form supercooled or supersaturated steam. When fine dust or charged particles are blown into it, the supersaturated steam will condense quickly.

This also shows that condensation nuclei are essential for the formation of clouds. The heat released by unit mass of liquefied steam as a liquid at the same temperature is called the condensation heat of this substance. The heat of condensation is actually equal to the heat of vaporization in quantity. For example, 1Kg steam is liquefied into water, and the heat of condensation is 539 calories =2253 joules.

Matters needing attention in summer:

The weather is getting hotter and hotter, and the utilization rate of refrigerators is higher. However, you should know that the refrigerator can only extend the shelf life of food, and it is not a foolproof "safe". If it exceeds a certain period of time, all kinds of foods stored in the refrigerator will lose their original deliciousness and nutrition.

Because some bacteria and viruses may have been brought in when food is put in, the temperature of the refrigerator is not zero, and many bacteria can lurk in a low temperature environment. If you wait for a long time, you will wait for opportunities to breed and make waves, so that the preserved food will be moldy, corrupt and spoiled. Therefore, the following precautions must be taken:

1. The food in the refrigerator must be clean and tidy. Raw food such as fruits and vegetables can only be put in after washing and draining. Raw fish, chickens and ducks should be eviscerated first, washed with clear water, and then put into the refrigerator.

2. After using the refrigerator for one to two weeks, wipe it once or twice with a soft cloth soaked in warm water. Do not use washing powder, detergent or gasoline to wipe.

3. Raw food and cooked food should not be put in one container, and raw vegetables and fruits should not come into contact with raw meat and raw fish to prevent bacterial contamination.

There should be a certain gap between the foods in the refrigerator. Don't cling to the left and right back walls of the refrigerator to facilitate cold air convection. The refrigerator should not be too full.

5. Try to reduce the time and frequency of opening the refrigerator door and reduce the entry of hot air from outside. The author understands that food should not be put into the refrigerator for more than five to seven days, and the food taken out should not be eaten again if it is found to be moldy, corrupt and stale.

6. Hot weather in midsummer, cold drinks, cold drinks, fruits, food, etc. After being taken out of the refrigerator, it should be placed at room temperature before eating, so as to avoid the sudden stimulation of cold drinks causing stomach pain, enteritis, diarrhea or aggravating the original diseases such as hypertension, coronary heart disease and stroke, especially for the elderly and children.

7, the refrigerator is also exquisite, generally pay attention to the following two issues:

When placing the refrigerator, it is generally necessary to reserve 5- 10 cm on both sides, 10 cm above and 10 cm behind, which can help the refrigerator to dissipate heat. Don't put it with audio, TV, microwave oven and other electrical appliances. The heat generated by these appliances will increase the power consumption of the refrigerator.

Baidu encyclopedia-refrigerator