Regarding the question of air pressure, what factors affect the magnitude of air pressure?

I think so, your teacher is really weird. As long as the volume of the solid increases when it becomes liquid, it will definitely become solid when pressurized. But water can't, because water is anti-expansion, and pressurizing the ice makes it liquid.

So it really depends. Your teacher is too categorical.

It is not that the phase change can occur under pressure, and it is recommended that you look at the phase diagram of the gas-liquid-solid three states, one phase diagram for each substance.

To give you a three-phase diagram of water:

Personally, I don't think it's general, because there are other factors. For example, temperature, I remember my teacher said in junior high school: some gases can be liquefied when they are cooled, such as water vapor; Some cannot, for example, oxygen, which must be cooled and pressurized.

As far as I know, there is solid air on Pluto, but it seems to be caused by low temperatures and has little to do with pressure. I think it should be said: "It's hard but not impossible".

I suggest you ask your teacher this question, and when you ask it, tell your teacher this question, and he will definitely give you a satisfactory answer after listening. Because I'm a teacher, if a student asks a question like this, it means that they're using their brains.

That's definitely pulling. The air expands and the volume increases.

According to the formula. Density.

Mass volume, mass must increase volume, density of course smaller. It's the same thing with air columns.

Volume is certain. The density is less.

The mass is of course lighter.

Categories: Education, Science, >> Science & Technology.

Problem description: During the Magdeburg hemispheric experiment, if the atmospheric pressure was standard atmospheric pressure at that time, the pressure of the remaining air in the ball would be a standard atmospheric pressure after the first pumping; After the second pumping, the pressure of the remaining air in the ball is one standard atmosphere. In these two cases, the ratio of the tensile force used to pull the two hemispheres apart is f1:f2

Analysis: At that time, the atmospheric pressure was one standard atmosphere (1atm) for the first pumping.

If the pressure inside the ball is sailing, then the difference between the internal and external pressure is δp1=(

Second pumping.

The pressure inside the sphere is , then the difference between the internal and external pressure is δp2=(

The area where the atmospheric pressure acts is the same.

Pressure f=ps

The ratio of the pressure difference between the two times.

f1δ/f2=（δp1*s）/(p2*s)=

Air has a weight of exerting pressure. The more air, the heavier the weight and the stronger the pressure. The depth of the air – the atmosphere.

The thickness varies depending on the topography of the earth. At the top of the mountain, there is less air, hence the atmospheric pressure.

It's lower than the air pressure in a valley.

Air pressure is also affected by temperature, which indicates the degree of molecular movement. Air molecules are constantly moving back and forth with each other, and any molecule around them may happen to collide with them. This impact, in turn, generates heat.

Therefore, the stronger the air pressure, that is, the more molecules collide with each other, and the higher the air temperature. In addition, the greater the number of moving molecules, the more space they occupy. So, for a given volume of warm air and cold air of the same volume, the former contains less molecules than the latter.

The lesser density of warm air means that it is lighter and more likely to rise than the denser, heavier, cooler air that tends to sink.

What are the factors that affect the magnitude of atmospheric pressure, the change of atmospheric pressure and altitude? The higher you are above the ground, the thinner the atmospheric pressure will be, and the lower the atmospheric pressure will become, and the base layer will be subjected to the gravitational force related to the void. The change of atmospheric pressure, so the atmospheric pressure decreases with the height is also uneven, the change of atmospheric pressure is also related to the weather, the atmospheric pressure in the same place is exactly the same between different places, we know that the density of water vapor is smaller than the density of air, way, when there is more water vapor, the air density will become smaller and the atmospheric pressure will also decrease, generally speaking, the atmospheric pressure on a rainy day is smaller than that on a sunny day, and the sudden decrease in atmospheric pressure on a sunny day is a precursor to the rain, and it has rained heavily for several days, It is found that the atmospheric pressure is expected to be transformed when the atmospheric pressure increases, and the change is also related to the temperature, so the air density becomes less when the temperature is high, so the atmospheric pressure is lower than the air temperature when the temperature is high.

The force on the unit area of an object is called pressure, which is often customarily called "pressure" in engineering technology, expressed in p, and the unit is pa (pa), where the pressure (pa) expressed by absolute vacuum (zero pressure) as the benchmark is called absolute pressure; The pressure (pg) expressed in terms of actual atmospheric pressure is called gauge pressure; The pressure (ps), expressed in reference to standard atmospheric pressure, is called the sealing pressure; The gauge pressure (also called vacuum) when it is less than the actual atmospheric pressure is called negative pressure.

The International System of Units (SI) uses Pascal as the universal unit of pressure, expressed in Pa or Pa. For example, when the force used for an area of 1 m2 (square meter) is 1 n (Newton), it is 1 pa (Pascal), which is expressed by the following formula:

pa=n/m2

Tips: Unit conversion of pressure and pressure: 1 bar (bar) = 105 Pa, 1 Pa = 1n S2 (Newtons per square meter), 1 standard atmosphere = ; 1mmHg (millimeter mercury column) = .

Barometric pressure is the atmospheric pressure acting on a unit area, i.e., the gravitational force exerted on a vertical column of air that extends up to the upper boundary of the atmosphere per unit area. The famous Magdeburg Hemispheric Experiment.

Proof of its existence. The SI unit of air pressure.

It is Pascal, abbreviated as Pa, and the symbol is Pa.

Meteorology. People generally use kilopascals (kpa) or hectopa (hpa) as the unit. Other commonly used units are:

bar (1 bar = 100,000 Pa) and a centimeter of mercury (or centimeters of mercury). Air pressure varies not only with altitude but also with temperature. Changes in air pressure are closely related to weather changes.

The atmospheric pressure is created as a result of the gravitational pull of the Earth, due to which the atmosphere is "sucked" towards the Earth, thus creating pressure, which is greatest near the ground. In meteorological science, air pressure refers to the weight of the atmospheric column (atmospheric pressure) per unit area, that is, the pressure exerted by the atmospheric column per unit area.

There are two units of air pressure: millimeters and millibars: the height of the mercury column is used to express the unit of air pressure, and the unit of air pressure is millimeters (mm). For example, a barometric pressure of 760 mm means that the atmospheric pressure at that time is equal to the pressure generated by the mercury column at a height of 760 mm.

The other is millibars (MB), which are often heard on weather forecast radios. It is a unit that expresses the level of air pressure by the amount of atmospheric column pressure per unit area. 1 mbar 1000 dynes square centimeter (1 bar 1000 mbar).

Therefore, 1 millibar represents a force of l000 dynes on an area of l square centimeters. A pressure of 760 mm is equivalent to millibars, and this pressure value is called one standard atmosphere.

Air pressure varies with the altitude of the atmosphere. The higher the altitude, the lower the atmospheric pressure; The greater the difference in altitude between the two places, the greater the difference in air pressure.

The weight of the atmospheric column is also affected by the change in density, and the denser the air, that is, the more mass of air per unit volume, the greater the atmospheric pressure it generates.

Since the mass of the atmosphere is denser to the ground and thinner the higher it is at altitude, the change in air pressure with altitude is also greater the closer to the ground. For example, in the lower layers, the air pressure decreases by about 10 millibars for every 100 metres of ascent. At an altitude of 5 6 km, for every 100 meters of ascent, the air pressure decreases by about 7 millibars; At an altitude of 9 10 km, for every 100 metres of ascent, the air pressure decreases by only about 5 millibars.

Air pressure changes all the time. Under normal circumstances, the air pressure rises in the morning and decreases in the afternoon; The air pressure is highest in winter and lowest in summer. Sometimes, for example, during a cold wave, the air pressure rises quickly, and the air pressure slowly decreases as soon as the cold air passes.

The pressure exerted by the atmosphere on an object submerged inside it.

Standard value: PO = 760 mmHg

The air pressure telescopic rod of the air pressure lift chair is filled with high-pressure nitrogen.

If you want to save money, you may be able to inject high-pressure air.

Now let's look at it as a balloon that hasn't reached a tipping point yet.

When he is not pressed, the pressure inside is the lowest state of his accumulation.

When you squeeze him.

The internal pressure increases.

It is possible when the breaking point is exceeded.

So. Give it the longest stretch to compare won't**.

Usually its load test and impact test are 200 kg.

Remember to report it if you **.

The above is an excerpt from the Internet, and I will share my own opinion below.

I've also seen the news of the air pressure chair**, and I'm really shocked, but we can't waste food because of choking! Nothing is completely safe.

The matter of the air pressure chair**, I have grown so big or heard of it for the first time, don't we buy it after hearing it once? On the contrary, we can hear about plane crashes and car accidents almost every day, so don't we take planes and cars?

In my opinion, you can still buy an air pressure chair, choose a more expensive one when you buy it, and it is no problem to choose a thicker air pressure tube. Thank you!

Atmospheric pressure is the atmospheric pressure acting on a unit area, that is, the gravitational force that is numerically equal to the vertical column of air that extends up to the upper boundary of the atmosphere per unit area. The famous Magdeburg hemispheric experiment proves its existence. The SI unit of air pressure is Pascal, abbreviated Pa, and the symbol is Pa [1].

In meteorology, people generally use kilopascals (kpa) or hectopa (hpa) as the unit. Other commonly used units are: bar (1 bar = 100,000 Pa) and centimeters of mercury (or centimeters of mercury).

Air pressure varies not only with altitude but also with temperature. Changes in air pressure are closely related to weather changes.

From the point of view of the molecular motion of air, it is the result of the combined action of the molecular motion of the air and the gravitational field of the earth. Under this combined effect, the impact force exerted by many air molecules on a plane per unit area at an average of each moment is expressed as air pressure. Where the density of air molecules is high, it is also the place where the average kinetic energy of air molecules is large, so the impact force is greater, so the air pressure is also greater.

Temperature: high air pressure, low air pressure, low temperature high air pressure.

Reason: The air column is relatively light at high temperatures, and heavy on the contrary.

Altitude: low air pressure at high altitude and low air pressure at high altitude.

Reason: The length of the air column can be seen as the upper limit of the atmosphere, so the high altitude, the short air column is low, and vice versa, the air pressure is high.

Air movement: The updraft corresponds to the high air pressure, and the downdraft corresponds to the high air pressure of Yandanhuai.

Rationale: The pressure of the downdraft on the lower surface is relatively large, and the pressure of the updraft on the lower surface is relatively small.

The air pressure varies with the height of the atmosphere because the air itself has weight, and the earth has a gravitational pull on matter, and the closer the center is, the greater the gravitational pull. Therefore, the closer the atmosphere is, the denser the scene, the thinner it is towards the upper altitude, and the air pressure also changes with the change of late mode air temperature, because the gas has the effect of thermal expansion and cold contraction, the temperature is low, the gas shrinks, the density increases, and the air pressure increases, on the contrary, the air temperature is high, the gas expands, and the density decreases small, so the air pressure also decreases.

Because high-pressure air masses are often entrenched in the air, the air pressure here is higher than the normal standard air pressure.

The increase in atmospheric pressure may be due to the fact that the temperature in the region is lower, causing the air to sink and form high pressure.