How to calculate pressure in a bottomless aquarium

In summary: So the pressure is going to be much lower at the top of the aquarium than it is at the bottom.HiIf you're not familiar with the term "gauge pressure" and "absolute pressure", take a moment to google for them. Then get clear in your mind which one you're asking about and why.I need to know how to determine the pressure at the highest pressure point in order to calculate the thickness of the glass needed for various sizes of bottomless aquariums.And if you answer those questions I asked you'll understand the physics involved well enough to do the calculation for yourself.
  • #1
Jerry Jewell
4
0
How do I calculate glass thickness on a bottomless aquarium where air pressure is holding the water up. Example: 18"x18" by 36"' high closed top. 6" of the aquarium is submerged in a pond.
Thanks.
 
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  • #2
Jerry Jewell said:
How do I calculate glass thickness on a bottomless aquarium where air pressure is holding the water up. Example: 18"x18" by 36"' high closed top. 6" of the aquarium is submerged in a pond.
Thanks.
What do you expect the pressure to be at the same level as the surface of the pond?

There's only so high that a bottomless aquarium can be - go above a certain height (about 10 meters) and the water level will won't rise with the closed top and instead a vacuum will form underneath the top. What is the pressure of the water at that height going to be?

If you're not familiar with the term "gauge pressure" and "absolute pressure", take a moment to google for them. Then get clear in your mind which one you're asking about and why.
 
  • #3
Hi
Thanks.
I need to know how to determine the pressure at the highest pressure point in order to calculate the thickness of the glass needed for various sizes of bottomless aquariums.
 
  • #4
Jerry Jewell said:
Hi
Thanks.
I need to know how to determine the pressure at the highest pressure point in order to calculate the thickness of the glass needed for various sizes of bottomless aquariums.
And if you answer those questions I asked you'll understand the physics involved well enough to do the calculation for yourself.

(Physics Forums has a policy against spoon-feeding people the answers to their questions - we're about understanding physics, not just calculating answers).
 
  • #5
I understand your desire to have members figure it out by themselves. But what happened to mentoring? I've talked with a structural engineer and two phd physics professors and all have been a bit baffled by the problem. If YOU don't know how to help please let other members chime in.
 
  • #6
It's physics for 15-year old students... It's hard to imagine engineers and physics professors baffled by so simple a question...
 
  • #7
If it's so simple why hasn't anyone done it ?
 
  • #8
Jerry Jewell said:
If it's so simple why hasn't anyone done it ?
We've been waiting for you to post your answers to the two questions posed in post #2 of this thread. If you aren't sure, go with your best efforts.

There's a fair chance that once you've found the answers to those questions, the rest of the problem will suddenly become simple... But if it doesn't we can walk you through the next step.
 
  • #9
Jerry Jewell said:
How do I calculate glass thickness on a bottomless aquarium where air pressure is holding the water up. Example: 18"x18" by 36"' high closed top. 6" of the aquarium is submerged in a pond.
Thanks.
Use the search function, we had this already. The key is: A normal aquarium frame is designed to hold the glass against the force from the inside, not from the outside.
 

1. How is pressure calculated in a bottomless aquarium?

In a bottomless aquarium, pressure is calculated using the formula P = ρgh, where P is the pressure in Pascals (Pa), ρ is the density of the fluid in kilograms per cubic meter (kg/m3), g is the acceleration due to gravity in meters per second squared (m/s2), and h is the depth of the fluid in meters (m).

2. What is the unit of measurement for pressure in a bottomless aquarium?

The unit of measurement for pressure in a bottomless aquarium is Pascals (Pa). Other commonly used units include atmospheres (atm), millimeters of mercury (mmHg), and pounds per square inch (psi).

3. How does the depth of the fluid affect the pressure in a bottomless aquarium?

The depth of the fluid directly affects the pressure in a bottomless aquarium. As the depth increases, so does the pressure. This is because the weight of the fluid above exerts a greater force on the bottom of the aquarium, resulting in an increase in pressure.

4. Does the type of fluid in a bottomless aquarium affect the pressure?

Yes, the type of fluid does affect the pressure in a bottomless aquarium. The density of the fluid, as well as its compressibility, will impact the pressure calculation. For example, a denser and less compressible fluid will result in a higher pressure compared to a less dense and more compressible fluid at the same depth.

5. Can the pressure in a bottomless aquarium be negative?

No, the pressure in a bottomless aquarium cannot be negative. Pressure is a measure of the force exerted by a fluid on an object, and it is always positive. However, it can be lower than atmospheric pressure if the aquarium is not completely filled with fluid. In this case, the pressure will be equal to the pressure at the surface of the fluid, which is typically atmospheric pressure.

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