# Water pressure and depth relationship goals

### Pressure and Pascal's principle (part 1) (video) | Khan Academy

Water pressure increases with depth because the water up above weighs down on the water below. You can find the pressure at any given. The purpose of this experiment is to determine the relationship between depth and pressure. Pressure and depth have a directly proportional relationship. respect to the relationship between pressure and volume, as the column of water has. Temperature is directly proportional to the depth inside Earth. In simple terms, it means the temperature increases as the depth increases inside See full.

### Pore pressure analysis - SEG Wiki

Traditionally, pressure is measured using a barometer, a device in which a column of liquid mercury, typically is pushed up by the air pressure outside. Imagine a flat surface at the depth for which you want to calculate the pressure. All you have to do is find the weight of all the water on top of that surface, then divide it by the area of the surface.

If you know the mass of an object, you can find the weight by multiplying the mass by the acceleration due to gravity. You can find the mass, m, of a body of water by multiplying its volume, V, by its density, r. Substituting our equation for the weight, W, into our original pressure equation, we get: Remember, volume is just length times width times height.

The length times width portion is simply the area, A. The height is the depth, d. So, the volume V can be rewritten as: The gravitational acceleration is 9.

## Pore pressure analysis

Putting these numbers in, we get a final equation of: A gas is compressible, which means that I could actually decrease the volume of this container and the gas will just become denser within the container. You can think of it as if I blew air into a balloon-- you could squeeze that balloon a little bit.

There's air in there, and at some point the pressure might get high enough to pop the balloon, but you can squeeze it. A liquid is incompressible. How do I know that a liquid is incompressible? Imagine the same balloon filled with water-- completely filled with water. If you squeezed on that balloon from every side-- let me pick a different color-- I have this balloon, and it was filled with water.

If you squeezed on this balloon from every side, you would not be able to change the volume of this balloon. No matter what you do, you would not be able to change the volume of this balloon, no matter how much force or pressure you put from any side on it, while if this was filled with gas-- and magenta, blue in for gas-- you actually could decrease the volume by just increasing the pressure on all sides of the balloon.

**Pressure and Depth**

You can actually squeeze it, and make the entire volume smaller. That's the difference between a liquid and a gas-- gas is compressible, liquid isn't, and we'll learn later that you can turn a liquid into a gas, gas into a liquid, and turn liquids into solids, but we'll learn all about that later.

This is a pretty good working definition of that. Let's use that, and now we're going to actually just focus on the liquids to see if we could learn a little bit about liquid motion, or maybe even fluid motion in general. Let me draw something else-- let's say I had a situation where I have this weird shaped object which tends to show up in a lot of physics books, which I'll draw in yellow.

This weird shaped container where it's relatively narrow there, and then it goes and U-turns into a much larger opening.

Let's say that the area of this opening is A1, and the area of this opening is A this one is bigger. Now let's fill this thing with some liquid, which will be blue-- so that's my liquid. Let me see if they have this tool-- there you go, look at that. I filled it with liquid so quickly. This was liquid-- it's not just a fluid, and so what's the important thing about liquid? Let's take what we know about force-- actually about work-- and see if we can come up with any rules about force and pressure with liquids.

## Pressure and Pascal's principle (part 1)

So what do we know about work? Work is force times distance, or you can also view it as the energy put into the system-- I'll write it down here. Work is equal to force times distance. We learned in mechanical advantage that the work in-- I'll do it with that I-- is equal to work out. The force times the distance that you've put into a system is equal to the force times the distance you put out of it. And you might want to review the work chapters on that.

That's just the little law of conservation of energy, because work in is just the energy that you're putting into a system-- it's measured in joules-- and the work out is the energy that comes out of the system. And that's just saying that no energy is destroyed or created, it just turns into different forms.

Let's just use this definition: Let's say that I pressed with some force on this entire surface. Let's say I had a piston-- let me see if I can draw a piston, and what's a good color for a piston-- so let's add a magenta piston right here.

I push down on this magenta piston, and so I pushed down on this with a force of F1. Let's say I push it a distance of D that's its initial position. Its final position-- let's see what color, and the hardest part of these videos is picking the color-- after I pushed, the piston goes this far. This is the distance that I pushed it-- this is D1. The water is here and I push the water down D1 meters. In this situation, my work in is F1 times D1.