Why boil water at a high altitude, the water boils very quickly 5

The temperature at which water boils is called the boiling point of water, and we usually say that "the boiling point of water is 100", which refers to the temperature at which water boils at one atmosphere (standard atmospheric pressure). So is the boiling point of water set in stone? No.

The boiling point of water varies with the atmospheric pressure: as the air pressure increases, the boiling point rises. Because the atmospheric pressure on the surface of the water always prevents water molecules from evaporating, when the air pressure rises, the water must have a higher temperature to turn into water vapor.

Generally at low altitudes, atmospheric pressure is basically one atmosphere. Boiling water at a place below sea level (e.g., in a very deep mine) where the air pressure is higher than one atmosphere, and the boiling point of the water rises, and it has been determined that an increase in depth of one kilometer increases the boiling point of the water by 3 degrees.

Conversely, when the air pressure decreases, the boiling point decreases. For example, the higher the altitude, the thinner the air and the lower the air pressure, the boiling point of water in this place decreases. Boil water on Mount Everest, the top of the world, and as soon as it is boiled, the water is boiled "boiled".

Such "boiling water" does not cook the meal and does not kill certain bacteria. For this reason, geologists and mountaineers use high-pressure cookers – pressure cookers – when working in the mountains. It is made using the principle of rising boiling point under high pressure.

The sealed lid prevents the vapor inside the pot from escaping, so the air pressure increases, the boiling point increases, and the meal cooks quickly. Under normal use, the air pressure in the household pressure cooker is an atmospheric pressure, and the temperature is generally around 125. When the air pressure in the pot is too high, the safety valve on the pot will automatically open to release a part of the vapor and reduce the air pressure.

The air in the highlands is thin and the air pressure is small, and the boiling point of water is reduced, so it is easy to boil.

The boiling point of water is harmed by air pressure, and the higher the air pressure, the higher the boiling point. And the higher the altitude, the lower the air pressure. Therefore, in the plateau, the boiling point of water decreases because of the decrease in air pressure.

The temperature of water boiling on the plateau is only about 70, the higher the altitude, the lower the air pressure, the lower the boiling point, the higher the altitude of the plateau, so the boiling point of water is low. To increase the boiling point, you need to increase the air pressure, and the pressure cooker is the basic principle. Water boils when the partial pressure circuit of the water vapor on the page is equivalent to the saturated vapor pressure of the water at that working pressure.

When the air pressure is high, due to the large number of gas molecular structures, the partial pressure circuit of water vapor on the page is not easy to achieve saturated vapor pressure, and the water is not easy to boil. That is, more and more water must be turned into vapor to occupy the part of the molecular structure of other gases. When the air pressure is low, the total number of gas molecular structures is small, and the molecular structure of water vapor can occupy all parts with a small total number, so water can boil at a lower temperature.

Characteristics of the plateau area:

The plateau has a high altitude, low air pressure, and low oxygen content, and the use of this natural environment of low voltage oxygen deficiency can improve the body's energy and physical literacy, so it has become a "blessed land" for endurance training in the football world.

In 1968, the 19th Olympic Games were held in Mexico City, a large city in the highlands, and the runners from the African highlands won 5 championships, 5 third places, and 2 third places in the middle-distance running and marathon races. Since then, the plateau has become a "blessed place" for the practice of physical events such as long-distance running, marathon races, and race walking in football around the world.

In addition, the plateau area receives a lot of solar radiation, has long sunshine hours, and is very rich in solar energy resources. The boiling point of water in the plateau area is less than 100, and if you cook in a regular rice cooker, it will be half-cooked.

The boiling point of a liquid

The boiling point of a liquid is positively correlated with air pressure, the higher the air pressure, the higher the boiling point, and the smaller the air pressure, the lower the boiling point. This principle is very easy to understand, when the water is boiling, you will see bubbles appear from the bottom of the pot, and then continue to increase until the surface of the river is destroyed. In this process, you can see that the "small bubble" is empty, full of gas, and has air pressure (called "blind saturated vapor pressure").

This air pressure slowly grows from small to large as the bubble grows, rises, and destroys, and finally becomes the same as the atmospheric pressure outside. Therefore, if the atmospheric compression is small, the bubbles will rise and die too early, and the water will boil early. If the atmospheric pressure increases, the water will boil later.

The higher the altitude, the lower the boiling point of water, because the higher the altitude, the lower the atmospheric pressure, and the boiling point of water will be correspondingly lower. At high altitudes, hail is not very hot even in boiling water. This is because the higher the altitude, the lower the atmospheric pressure, while the boiling point of the liquid decreases as the air pressure decreases.

The boiling point of water on the plateau does not reach 100, making it difficult to cook rice quickly.

Therefore, it is best to use a pressure cooker to cook rice on the Liangdan Plateau, which can increase the air pressure in the pot, increase the boiling point of water, and also increase the temperature of cooking food, which saves fuel and time.

The boiling point of water as well as the atmospheric pressure relationship. Respectfully.

The boiling point of water is 100 under standard atmospheric pressure, the lower the atmospheric pressure, the lower the boiling point, and the higher the atmospheric pressure, the higher the boiling point. When the pressure of the vapor is equal to the pressure of the outside, the vapor pressure has reached a saturated state, and the water will boil at this time, and the temperature of the water when it boils is the boiling point of the water.

When the external pressure increases, the pressure of the vapor will also increase, and at this time, the temperature needs to be raised to make the vapor pressure reach a saturated state, and at the same time, the boiling point of water will also increase, so the higher the atmospheric pressure, the higher the boiling point of water.

The above content refers to Xinhuanet - the truth! Does water have a boiling point of 100?

Reason: The boiling point of the liquid is related to the external pressure, when the pressure of the liquid increases, its boiling point increases; When the pressure decreases; The boiling point decreases. In high-altitude areas, water cannot be boiled because the atmospheric pressure decreases with the increase of terrain, and the boiling point of water also decreases with the increase of altitude.

At an altitude of 1900 meters, the boiling point of water is; And at an altitude of 5,000 meters, although the water in the pot is boiling, the total temperature does not exceed 85. Therefore, the high altitude does not boil water.

The higher the altitude, the lower the boiling point of water. At high altitudes, the air is thinner and the natural atmospheric pressure is smaller. The boiling point of water is related to the air pressure of the liquid surface, and the lower the air pressure, the lower the boiling point.

For example, the steam pressure in a steam boiler is about a few tens of atmospheres, and the boiling point of water in a boiler can be more than 200. For another example, when cooking rice in a high mountain, the water is easy to boil, but the rice is not easy to cook.

This is due to the fact that the atmospheric pressure decreases with the increase in the topography and the boiling point of water also gradually decreases with the increase in altitude. (At an altitude of 1,900 m, the atmospheric pressure is about 79,800 Pa (600 mm Hg), and the boiling point of water is that those with a low boiling point generally vaporize first, while those with a high boiling point are generally more difficult to vaporize.)

Different liquids. At the same atmospheric pressure, the boiling point of different kinds of liquids is also different. This is because the saturation vapor pressure is related to the type of liquid. At a certain temperature, the saturated vapor pressure of various liquids is also constant.

For example, at 20, the saturated air pressure of ether is Pa (44 cm Hg) lower than the atmospheric pressure, and the temperature rises slightly, so that the saturated vapor pressure of the ether is equal to the atmospheric pressure, and the ether can be boiled by heating it to 35.

If the liquid contains impurities, it will also affect the boiling point of the liquid. The boiling point of a liquid containing solute is higher than that of a pure liquid, which is due to the fact that the gravitational force between the liquid molecules increases after the presence of a solute, the liquid is not easy to vaporize, and the saturated vapor pressure is also smaller.

To make the saturation vapor pressure the same as the atmospheric pressure, the boiling point must be raised. Different liquids have different boiling points under the same external pressure. The boiling point changes with pressure, and the dust distribution relationship can be obtained from the Clausius equation.

At higher altitudes, the lower the air pressure, the lower the boiling point of water.