Effects of Pressure on Water: Explained

In summary, the effects of pressure on water can be confusing. Increasing pressure can increase the boiling point and temperature, as seen in the vapor compression cycle used in air conditioning. However, this effect is not permanent and can be reversed by the process of compression, cooling, and expansion. When applying pressure to water, it may not turn to ice immediately due to its unique crystal structure.
  • #1
dhulke
1
0
Hi!

So I'm pretty confused about the effects that pressure has on water. If I increase pressure, I increase the boiling point. Likewise, if I increase pressure I increase temperature. How's that?

That's the way air-conditioning works, by increasing pressure on one side and decreasing pressure on the other this way one side gets hotter and the other gets colder. But if by increasing pressure, temperature increases, shouldn't my deodorant bottle be hot?

And if I have water and I apply pressure, shouldn't it turn to ice at some point? I'm so confused... Can anybody help me?
 
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  • #2
You are confused about how air conditioning works. See this article (vapor compression cycle):

http://en.wikipedia.org/wiki/Refrigeration#Vapor-compression_cycle

A liquid boils when its vapor pressure equals or exceeds the ambient pressure acting on the free surface. Water boils at 100 C at sea level when the atmospheric pressure is 1 atmosphere. If you go to the top of a tall mountain, where the atmospheric pressure is less than 1 atmosphere, the boiling point of water is reduced below 100 C.
 
  • #3
Welcome to PF!
dhulke said:
But if by increasing pressure, temperature increases, shouldn't my deodorant bottle be hot?
Anything that is hot can be made cold again: the effect isn't permanent. If it was, air conditioning wouldn't work. So with air conditioning, it goes like this:

1. The gas is compressed and gets hot.
2. The gas is run through a heat exchanger to cool it (and some liquefies).
3. The gas is allowed to expand, cooling it.
And if I have water and I apply pressure, shouldn't it turn to ice at some point?
You'd expect that, yes, but ice has a crystal structure that makes it less dense than water. So it isn't that easy.
 

What is pressure and how does it affect water?

Pressure is the force per unit area applied on an object. In the case of water, pressure can affect its physical and chemical properties such as density, boiling point, and freezing point. Pressure can also influence the movement of water molecules and the formation of water droplets.

What happens to water when pressure is increased?

When pressure is increased, the volume of water decreases due to the compression of its molecules. This leads to an increase in density and a decrease in boiling point. As a result, water may turn into ice at a lower temperature than normal. Increased pressure can also affect the solubility of gases in water, making it more difficult for them to dissolve.

How does pressure affect the boiling point of water?

As pressure increases, the boiling point of water also increases. This is because the higher pressure compresses the water molecules, making it harder for them to escape into vapor form. As a result, more heat is required to reach the boiling point. This is why it takes longer to cook food at high altitudes where the atmospheric pressure is lower.

Can pressure affect the pH of water?

Yes, pressure can affect the pH of water. When water is under high pressure, it can become slightly acidic due to the formation of carbonic acid from the reaction between water and carbon dioxide. This can be seen in deep ocean waters where the pressure is significantly higher than at the surface.

How does pressure impact the movement of water in the ocean?

Pressure plays a crucial role in ocean circulation. The differences in pressure between different areas of the ocean create currents that help distribute heat and nutrients throughout the ocean. These currents also play a vital role in regulating the Earth's climate. Changes in pressure can also cause ocean waves, which are crucial for erosion and the movement of sediments along coastlines.

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