Can Oxygen Pass Through Water in a Suspended Tank?

AI Thread Summary
In a suspended tank of water with small holes, oxygen molecules can theoretically pass through the holes, but their movement is influenced by various forces. The downward force from the water column and air pressure above creates a situation where the oxygen's upward movement is limited. While some oxygen molecules may penetrate the water due to their kinetic energy, there is an equal chance for water molecules to escape through the holes. The overall dynamics suggest that the water's weight and pressure would impede the consistent upward flow of oxygen. Thus, while oxygen can occasionally pass through, it is not a straightforward process.
Idea04
Messages
194
Reaction score
1

Homework Statement


I know with air bubbles in water that they will rise in water because they are lighter and less dense than water.
But if you had let's say a tank of water suspended in the air and at the bottom of the tank there were small holes so small that air can go through the holes but water couldn't.
Would the oxygen pass through the holes and rise in the water, or would the oxygen be blocked by the water molecules.


Homework Equations





The Attempt at a Solution


I kind of think that the water would not allow the air to move up because would the water want to move down words and since it couldn't the air will not flow. But I'm not sure on this.
 
Physics news on Phys.org
Idea04 said:

Homework Statement


I know with air bubbles in water that they will rise in water because they are lighter and less dense than water.
But if you had let's say a tank of water suspended in the air and at the bottom of the tank there were small holes so small that air can go through the holes but water couldn't.
Would the oxygen pass through the holes and rise in the water, or would the oxygen be blocked by the water molecules.

The Attempt at a Solution


I kind of think that the water would not allow the air to move up because would the water want to move down words and since it couldn't the air will not flow. But I'm not sure on this.
Let the area of a hole = A. Consider a thin disk of water of area A and thickness ds. What is the total force on the thin disk of water covering the hole?

The forces are gravity (down) air pressure (up) and water pressure (down). (we will ignore surface tension).

The downward force consists of the weight of the column of water above the hole + downward air force (air pressure x A) on that column. The upward force is just the air pressure x A. You can see that the atmospheric pressures above and below cancel each other and you are left with the downward weight of the column of water. So which way does the water go?

AM
 
So if you went to a microscopic level and you had a hole the size of of an oxygen atom and at the bottom there was oxygen atoms and above were water molecules which are larger than oxygen. take in the account that molecule and atoms all have large space between them. Wouldn't some oxygen molecule be absorbed by the water.
 
Idea04 said:
So if you went to a microscopic level and you had a hole the size of of an oxygen atom and at the bottom there was oxygen atoms and above were water molecules which are larger than oxygen. take in the account that molecule and atoms all have large space between them. Wouldn't some oxygen molecule be absorbed by the water.
In my previous answer I showed that the force required to lift a column of water covering the hole and insert an oxygen molecule is greater than the average force of impact of an oxygen molecule on the water (ie. the air pressure). Is there another way to get an oxygen molecule into the hole?

Because the molecules of oxygen are not all moving at the same speed, occasionally an oxygen molecule with sufficient energy may strike the water over the hole with enough force to penetrate into the water. But there is an equal likelihood that an oxygen molecule will go the other direction (from the water, out the hole).

AM
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...

Similar threads

Back
Top