Understanding Pressure in Liquids

In summary, you are trying to figure out how the pressure changes in liquids. The pressure in the small tube increases as the water rises, due to Boyle's Law. The pressure at the yellow and pink marks are the same.
  • #1
hms.tech
247
0
I can't seem to get a clear picture of how the pressure changes in liquids.

Here is a small self made file, made to make myself understand this topic .



Click on the attachment.

Obviously as the water rose up, air pressure in the small tube rose up. (Due to Boyle's Law)

Now let's assume (for the sake of better understanding) that i pushed the small tube half a meter inside the large beaker.

Now what is the pressure on the yellow mark ?
Is it equal to the air pressure inside the small tube, because that only makes sense. If they were not equal then there would be no Equilibrium and the water would continue to rise up/down.

And, what is the pressure at the pink mark ?
Is it :

Pressure = Desnsity x g x h + atm
= 1000*9.8*0.5 +1atm


Is the pressure on both marks the same ?
 

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  • #2
Why did the water rise up the tube? I can't see a reason for that unless the tube is sealed at the top and the air in it was cooled between 1 and 2?

The only other way would be if the tube was open at the top and capillary action caused the water to rise a little way up the tube?
 
  • #3
So what u are suggesting is that the water level in the beaker remains constant, thus the awter in the small tube will not rise ?

If that is the case, then the pressure at the yellow spot must be the same as the pressure of the air in the small tube, while Pressure at the pink mark will be ?

1.Air pressure in the small tube(which is higher than 1atm) plus the pressure due to liquid water
OR
2.Air pressure (1 atm) plus the pressure due to liquid water

I think it would be 1.

Am i correct ?
 
  • #4
Bump

Is there no one who can help me ? :(
 
  • #5


I can understand your confusion about pressure in liquids. It can be a complex concept to grasp, but I'll try my best to explain it clearly.

First, let's talk about the basic principles of pressure in liquids. Pressure is defined as the force exerted per unit area. In the case of liquids, this force is due to the weight of the liquid above a certain point. So, the deeper you go in a liquid, the more weight and pressure there is above you.

Now, let's look at your experiment. When you pushed the small tube half a meter inside the large beaker, you essentially increased the depth of the water above the yellow mark. This means that the pressure at the yellow mark has also increased. This is because the weight of the water above it has increased, leading to an increase in pressure.

As for the pink mark, the pressure there is also determined by the weight of the water above it. However, in addition to the weight of the water, there is also the air pressure acting on the surface of the water. This is why you correctly calculated the pressure at the pink mark to be the sum of the weight of the water and the atmospheric pressure.

To answer your question, the pressure at the yellow mark and the pink mark are not the same. The pressure at the yellow mark is only determined by the weight of the water above it, while the pressure at the pink mark is determined by the weight of the water and the atmospheric pressure.

I hope this helps to clarify your understanding of pressure in liquids. It's important to remember that pressure is not constant in liquids and can vary depending on depth and external factors such as atmospheric pressure. Keep exploring and experimenting, and you will continue to gain a better understanding of this concept.
 

1. What is pressure in liquids?

Pressure in liquids is the amount of force exerted by a liquid per unit area. It is typically measured in units of Pascals (Pa) or pounds per square inch (psi).

2. How is pressure in liquids different from pressure in gases?

Unlike gases, liquids are relatively incompressible, meaning their volume does not change significantly under pressure. This is because liquids have much stronger intermolecular forces compared to gases, making it difficult for them to be compressed.

3. What factors affect pressure in liquids?

Pressure in liquids is affected by the depth of the liquid, the density of the liquid, and the acceleration due to gravity. Additionally, any external forces acting on the liquid, such as gravity or applied pressure, can also affect the pressure.

4. How is pressure in liquids measured?

Pressure in liquids can be measured using a variety of instruments, such as a manometer or a pressure gauge. These instruments typically measure the height of the liquid column or the force exerted by the liquid, which can then be converted to a pressure measurement.

5. What are some real-world applications of understanding pressure in liquids?

Understanding pressure in liquids is important in many industries, such as hydraulic systems, water distribution, and scuba diving. It is also crucial in understanding weather patterns and ocean currents, as changes in pressure can affect the movement of fluids in the atmosphere and oceans.

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