White dew and cold dew belong to two of the 24 solar terms in my country. These two solar terms are both after autumn and represent changes in weather temperature. Relatively speaking, the temperature is higher in the white dew. At this time, it is recommended not to expose your arms and legs, so as to keep warm. After entering the cold dew, it is more necessary to put on socks to keep your feet warm and protected, so as to prevent you from getting sick. This proverb, "Body exposed in white, bare feet uncovered in cold weather," reminds people of changes in the weather and makes them pay attention to changes in clothing, so as to prevent the body from getting sick. To be precise, entering the white dew season means that the weather is getting colder, so it is not advisable to go bare-chested; during the cold dew season, the weather is even colder, so you need to pay attention to keeping your feet warm. In fact, it is very easy to understand. The ancients have always followed this custom to add clothing and pay attention to keeping warm.
Temperature changes
Bailu is the 15th solar term of the year. At this time, the position of the sun shifts to 165 degrees of ecliptic longitude, entering the Mid-Autumn Festival of autumn. Although the ancients were not as technologically advanced as today and could accurately measure the changes in weather temperature to remind themselves to add more clothes, they knew how to grasp the time of sunrise and sunset. The origin of the name "Bailu" is recorded by the ancients: "Water, soil, and moisture condense into dew." Autumn belongs to gold, gold is white, and white is the color of dew, and the air starts to get cold. ?
This record clearly shows that after entering the white dew, the moisture in the water and soil will condense into dew. It may continue to be hot during the day, but it will gradually feel chilly at night, and the temperature difference is also relatively large at this time. , which can accelerate the condensation of water vapor in the air into water droplets.
Changes in intervals
The difference between cold dew and white dew is 30 days, which is one month, and the temperature is lower at this time. It is recorded in "The Collection of Seventy-Two Hours of the Moon Order": On the ninth day of the ninth month, the dew will be cold and will condense. ?This means that the water at this time can condense into dew at night, which is obviously colder than white dew, and can even condense into frost. At this time, it is recommended that people should not expose their feet.
In ancient times, although people were not as advanced in using technology today, they were good at discovering common phenomena in life. For example, water vapor. Everyone knows that when the weather is hot and it rains, it is easy to form water vapor. But when the temperature drops, the water vapor will gradually decrease and gradually become dew. If the temperature is lower, then It's frost.
Changes in health preservation
In ancient times, although the lifestyles were different, people also paid great attention to health preservation. For example, the body is not exposed when it is white, and the feet are not exposed when it is cold. It is for these two solar terms. , pay attention to the measures to prevent cold and heat preservation. In addition to paying attention to adding clothes during this solar term, people also need to prevent dryness in autumn. There is less rain in autumn, the weather is prone to dryness, and the temperature gradually drops. At this time, it is cold outside and hot inside, and people are prone to colds and illnesses.
So after entering autumn, people need to prevent dryness, pay more attention to lung diseases, and eat more foods that are good for the lungs. For example, white foods are good for the lungs, such as yams, lilies, white fungus, and carrots. Waiting for these, drinking more soup and eating more porridge will be of great benefit to the human body.