What is the reason for not using atmospheric pressure as a unit in China?

It is not that the use of domestic units is not allowed, but the internationalization of units is an international trend, and now all international exchanges use the International System of Units units, and the units of standard atmospheric pressure are gradually used less, and some old instruments in the industry are still using industrial air pressure, but the new instruments are using megapascals.

The reason why the unit of atmospheric pressure is not allowed in China is that it is in line with international standards, and the international system of units is used: Pascal.

Air pressure and boiling point The boiling point of a liquid generally varies with the pressure of the surrounding atmosphere, when the air pressure is low.

, the boiling point of water decreases. On the plateau of more than 6,000 meters, the air pressure is low, the water is boiled at 80, the water begins to fully vaporize, the temperature no longer rises, and the rice is not cooked. And in the pressure cooker.

Inside, due to the high air pressure, valence and electrons must have a high rate to reach boiling, so the temperature in the pot is also high, more than 100, so that the pressure cooker cooks quickly cooked. Because in the molecules of gas, the valence and electrons are in three-dimensional operation, and the shell formed by the operation makes the molecules repulsive, when the pressure is high, the distance between the molecules is forced to be closer, and the repulsion force generated by the valence and electrons interferes with each other, and the core increases the rate of valence and electrons to increase the repulsion force and the frequency of the repulsion force.

The number of occurrences per second of each part) valence and the rate of electrons are high, and the temperature of the substance increases. Conversely, the pressure decreases, the distance between the molecules increases, and the valence and electron rates are correspondingly lower. When water is under greater pressure, valence and electrons must have a higher rate to produce enough repulsion to form vaporization.

And for the valence and electrons to have a higher rate, it must have a higher temperature, so when the pressure is high, the boiling point of water is high. When the plateau air pressure is low, the valence of water and the rate of electrons do not need to be very high, and there is enough repulsion to push the distance between the molecules, and the conditions for vaporization to occur are reached. That is, when the water temperature is not very high, internal vaporization has taken place, so the boiling point is low.

Answer, support me.

1. First of all, it is clear that the atmospheric pressure near the ground is almost equal, that is, the atmospheric pressure above and below the roof is equal, and according to f=ps, the pressure up and down the roof is also equal, so the roof balance will not be crushed. There are two mistakes in your understanding: first, the internal and external air pressure is generated by atmospheric gravity above the roof, not the air pressure in the room is generated by the gas in the room; 2. Will there be a difference in the height of the internal and external gases due to the thin roof? As a matter of fact.

The inner and outer atmospheres are connected and the gases are fluid, so the pressure is equal.

2. The atmospheric pressure on the roof is downward, and the atmospheric pressure in the room is upward on the roof, and the upper and lower pressures are equal, so the roof is in a state of equilibrium and will not be crushed. As for the pressure on the stone, it is another problem, the force has two effects, changing the motion of the object from rest to motion, changing the shape of the object, and the problem you add belongs to the latter type.

3. The left and right hands give force is mutual, the left hand gives force to the right hand when the right hand also gives the left hand, and it is equal, without the right hand, the left hand can not give force, so the pressure of the left and right hands for the first time is 10N, and the pressure of the left and right hands is 13N for the second time.

1. Your understanding is not entirely correct, it is true that the air pressure does not want to wait, but the lower the altitude, the greater the air pressure, so the hydrogen balloon will fly into the sky, because the buoyancy generated by the unequal pressure above and below is greater than the gravity, 2 atmospheres = Pascal, not enough to press the bie stone, bones, stones are composed of molecules, and there will be no interaction force within the molecule, which will cancel out the pressure from the outside.

3. The pressure of the left and right hands is 10N, if the right hand is 13N, the pressure between the left and right hands is the interaction force, and the interaction force is equal and the direction is opposite, so the pressure of the left and right hands is 13N

Hehe: That's too hard, isn't it?

You mean to turn the bottle upside down, if so, the bottom of the bottle is a vacuum, then the height of the bottle is at least: h=p (water g)--p is the atmospheric pressure outside.

According to the standard atmospheric pressure: p = is 10 to the 5th power).

h water = that is, a standard atmosphere can support a high column of water, if the bottle is higher than this height, the higher part is the vacuum.

The vacuum height of this section is not fixed (related to the local atmospheric pressure at the time, and related to the height of the bottle).

If the atmospheric pressure changes, use the real atmospheric pressure instead of the standard atmospheric pressure value to recalculate the H water, please click to adopt, you can ask if you don't know.

101300 1000 10 = meters.

The height of the liquid level is maintained in meters.

Not fixed, subtract by the height of the bottle.

1.Objects generally do not ignore large changes in air pressure.

2.The objects are surrounded by air, and the atmospheric pressure action cancels each other out.

The object is still in the horizontal plane, so why is the pressure of the object on the horizontal plane only equal to the gravitational force of the object and not the atmospheric pressure.

3.If the contact surface is absolutely flat and no air enters the atmosphere, the pressure comes into play, which can be determined by the symmetry, microelement method.

The net force of an irregular object under atmospheric pressure is 0

1. Generally speaking, there is atmospheric pressure around the space object, even if it is a very delicate wooden block placed on a very smooth wooden board, there are capillaries between the contact surfaces, and the resultant force of the object under atmospheric pressure is 0;

2. Two "absolutely" tight pieces of plastic (or film) overlap and are difficult to pull apart, mainly due to atmospheric pressure.

3. Only a small part of a large stone at the bottom of the lake is exposed on the mud surface, and the pressure on the stone = water pressure + atmospheric pressure.

The weight of the suction cup is inside the air that goes in. The air inside has downward pressure on the suction cup. Force Analysis:

Ideal force: The suction cup is subjected to the tension of the heavy object and the pressure of the outside air, and when the two forces are balanced, the suction cup falls off. Actual Force:

The suction cup is pulled down by the external air pressure and the internal air pressure, which causes the weight to be pulled down when it is light. Thus smaller than it actually is.

With a pull of the suction cup, the area decreased.