Impossable with a pump to suck water from a lake

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    Lake Pump Water
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Discussion Overview

The discussion revolves around the question of why it is impossible to use a pump to suck water from a lake when the pump is positioned 15 meters above the water level. Participants explore the physical principles involved, particularly the effects of gravity and atmospheric pressure.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that gravity is a key factor in the inability to pump water from such a height.
  • Another participant questions the limitations of pump size, proposing that a sufficiently large pump could overcome the height issue.
  • A different viewpoint emphasizes that pumps do not suck water; they rely on atmospheric pressure to push water into the pump from below.
  • One participant references the mercury barometer to illustrate the limits of suction, noting that the maximum height of water that can be pumped is influenced by the density of the fluid and atmospheric pressure, specifically stating that an ideal pump can only lift water to about 10.34 meters at sea level.

Areas of Agreement / Disagreement

Participants express differing views on the mechanics of pumping water and the feasibility of overcoming gravitational limits, indicating that multiple competing perspectives remain without a consensus.

Contextual Notes

Participants discuss the theoretical limits of pumping based on atmospheric pressure and fluid density, but the conversation does not resolve the assumptions regarding pump design and operational conditions.

JBemp
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Hiya
my question is

Why is it impossible with a pump to suck water from a lake if you place the pump 15 meters above the water


I think it has somthing to do with gravity but if anyone could explain it in detail that would be great

Thanks :)
 
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Well yes the water is held down by gravity.
 


yes but i was thinking what stops me from making a pump so large the i can pump anyways
 


Pumps don't suck. They can only remove the air/water that is already in the line. Then the ambient air pressure pushes the water up. 14.7 psi = 33 feet of water= 10m of water.
 


Have you ever looked at a mercury barometer where the column of mercury is about 760 mm (millimeters) high, with vacuum above the column, and air pressure pushing from the bottom? There is no way that the suction (vacuum) can be made any better. Because the mercury density is 13.6 times higher than water, the absolute max column of water an ideal pump can suck is 760 mm x 13.6 = 10.34 meters (at sea level).
 

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