Understanding the Water Pump: Gravity and Atmospheric Pressure

In summary, the conversation is about a video explaining the mechanics of a water pump using a syphon. The person is curious about how the syphon works and why the first glass must be higher than the second. The answer is that the gravitational potential energy of the water in the first glass is needed for the syphon to work. The pressure difference between the top and bottom of the short tube allows water to flow up into the bottle, creating a fountain effect.
  • #1
Oomph!
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Hello.
I saw this video: ... it is about water pump.

I want to know how it works. First straw is above the water surface, second is below the water surface. To the straw below the water surface goes watter because force of gravity act on it. This is why air column increases and makes it underpressure. So, the underpressure acts to the water in first bottle and sucks the water to maintaining atmospheric pressure. It is right?

However, there is one think which I really don't understant. Why the first glass must be higher than second glass?
 
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  • #2
It's a syphon. See here: http://en.wikipedia.org/wiki/Syphon#Theory

The full glass has to be higher than the empty glass so that it has gravitational potential energy for the syphon to use. In other words, the water needs height to flow down the straw and suck water up the other straw. If the height of the glasses were the same, the water would have to flow the same distance up as it does down and there would be no difference in force.
 
  • #3
Water flows down the long tube because there is a difference in hydrostatic pressure between the top and bottom liquid surfaces. The pressure in the bottle is Atmospheric minus the above difference. So there is an overall negative pressure difference between the top and bottom of the short tube. Water goes up into the bottle because of this. The pressure difference is so great in the video that the water emerges at the top in a fountain.
 

1. How does a water pump work?

A water pump works by utilizing the force of gravity and atmospheric pressure to move water from a lower elevation to a higher elevation. The pump creates a vacuum, which causes the atmospheric pressure to push the water up and into the pump. The pump then uses mechanical energy to push the water further up and out of the pump.

2. What role does gravity play in a water pump?

Gravity plays a crucial role in a water pump. It provides the potential energy needed to move the water from a lower elevation to a higher one. Without gravity, the water would not be able to flow naturally, and the pump would not be able to function.

3. How does atmospheric pressure affect the water pump?

Atmospheric pressure is essential in creating the vacuum that allows the water to be pulled into the pump. As the pump creates a vacuum, the atmospheric pressure pushes the water into the pump and then into the discharge pipe.

4. What factors can affect the performance of a water pump?

Several factors can affect the performance of a water pump. These include the height and distance the water needs to be moved, the size and type of pump, and the quality and consistency of the water being pumped.

5. What are some common problems with water pumps?

Some common problems with water pumps include clogging, air leaks, and mechanical failures. Clogging can occur when debris or sediment builds up in the pump, obstructing the flow of water. Air leaks can also cause issues as they can disrupt the vacuum needed for the pump to function correctly. Mechanical failures can happen due to wear and tear or improper maintenance of the pump.

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