# Path of least resistance

• GammaRayBurst
In summary, the conversation discusses the air pressure distribution in a pipe placed in water and the potential implosion of a soda bottle filled with air at a certain depth. The experts explain that the air pressure in the pipe is constant but slightly higher at the bottom due to the weight of the air above it. The potential implosion depth for the soda bottle is estimated to be around 20 feet, and the experts mention the difference in strength between a cylinder and a sphere shape. They also discuss the possibility of inducing an implosion earlier with a low power means, such as electricity. The conversation ends with a question about a substance that can become solid with the application of electricity.
GammaRayBurst
If I put a 6 inch 40 foot pipe down into the ocean or large body of water, straight up and down, the bottom of the pipe is closed, top is opened above into the air, will the air pressure that has migrated down through the pipe be at a constant pressure as long as the pipe is strong enough to hold its shape?

novice...

Sounds like a homework problem, so I moved the thread to the homework forums.

Welcome to PF, GammaRayBurst. In your problem statement, would there be anything different between the situation you describe, and the same situation with no water? Like if you put the pipe in a lake with the open top above the surface, and then drained the lake. If the pipe is rigid...

That works for me, thanks.
Do you have any insight on under water implosions ?, like if a two liter pop with air inside was weighted to go down deep in the water, about how many feet would it take to implode?
By the way its not homework, been out of school since 79, just a home tinkerer.
thanks, don

Hi Don. In your original post (OP), you referred to a rigid pipe, so implosion wasn't part of the problem statement. In the case of the rigid pipe, then the water doesn't factor in at all. The air pressure distribution is the same as free air at that altitude throughout the pipe (a little higher at the bottom of the pipe, due to the slight weight of the air above it in the pipe).

But for a plastic soda torpedo tube that is weighted and sealed and dropped in a lake, it will sink relatively intact until a depth where the water pressure exceeds the crush strength of the container. Keep in mind that spheres and cylinders are pretty strong against outside pressure. They are less strong if they have a dent somewhere in them -- that keeps the forces from being even (isotropic) around the container, and helps them crush at a lower overall pressure/depth.

Does that make sense?

I meant a two liter bottle filled with air.
would it take about twenty feet or more before it imploded?

GammaRayBurst said:
I meant a two liter bottle filled with air.
would it take about twenty feet or more before it imploded?

That sounds like a good guess, but I don't know for sure. I see an experiment in your Thanksgiving weekend plans...

And you understand that it's the straight sides of the cylinder shape that make the bottle crush at such a shallow depth, right?. A perfect plastic sphere would last much deeper.

EDIT -- Changed my typo cylinder --> sphere in my last sentence.

I want the tube to be solid, but the bottle would be like a collapsible bladder.

You said: The air pressure distribution is the same as free air at that altitude throughout the pipe (a little higher at the bottom of the pipe, due to the slight weight of the air above it in the pipe.

so the density of the air would be heavier at the bottom of the pipe?

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GammaRayBurst said:
so the density of the air would be heavier at the bottom of the pipe?

Yes, the same as it is for normal atmospheric situations. The density of air is higher at sea level than it is at 10,000 meters up, right?

Thanks again, I guess I should have already known this, but I seem to be having a lot of brain farts on this project, but so far so good.
Appreciate the help!

Can one induce an implosion earlier in the bottle before it reached its crush depth by a simple low power means?
perhaps a current from a stungun that is wired into the bottle.
PS, just thinking in theory.

Also, can anyone remind me of the liquid that when you apply an electric current, it becomes a solid?

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## What is the "path of least resistance"?

The "path of least resistance" is a concept in physics that refers to the path that an object will naturally take when subjected to a force. It is the path that requires the least amount of energy to overcome any resistance and reach its destination.

## How does the path of least resistance relate to electricity?

In electricity, the path of least resistance refers to the path that an electric current will naturally take through a circuit. This is determined by the conductivity of the materials in the circuit, with the current flowing through the path that offers the least resistance to its flow.

## What factors affect the path of least resistance?

The path of least resistance is affected by several factors, including the material through which the object or current is moving, the strength of the force applied, and any obstacles or barriers in the way. The path of least resistance will always be the path that requires the least amount of energy to overcome these factors.

## Is the path of least resistance always the shortest path?

No, the path of least resistance is not always the shortest path. It is the path that requires the least amount of energy to overcome resistance, which may not necessarily be the shortest distance. For example, in a circuit, the path of least resistance may involve going through a longer wire with higher conductivity rather than a shorter wire with lower conductivity.

## How is the path of least resistance used in engineering and design?

In engineering and design, the concept of the path of least resistance is used to determine the most efficient and cost-effective way to achieve a desired outcome. By identifying the path of least resistance, engineers and designers can minimize energy waste and optimize the performance of their designs.

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