For every 10 meters of sea depth, the pressure rises by around one atmosphere. At a depth of 5,000 meters, the pressure will be around 500 atmospheres, or 500 times higher than at sea level. That is a very high pressure that could cause problems for humans if they were exposed to it for long periods of time.
At any given location on Earth, the pressure increases as you go deeper under the surface. This is because there is less and less air above your position to weigh down on you as you descend into the ground.
At the surface of the planet, where the air is thick with moisture, the pressure is roughly equal in all directions. But as you sink deeper, the weight of the overlying rock and soil compresses the material between them and you. This leaves less space for it to expand into which reduces the pressure it places on you.
The bottom line is that pressure increases with depth and this increase in pressure can cause problems for humans if they are not protected from it.
Here on earth, the deepest place where people have lived sustainably for long periods of time is at a depth of about 930 meters below sea level in the Kiribati islands.
Each square inch of your surface is subjected to a force of 14.6 pounds if you are at sea level. This means that your body would experience conditions similar to those experienced by humans exposed to air pressures of 100,000 feet (30,480 m) above sea level.
At any given point beneath the ocean's surface, there may be water molecules in all directions. But the net force on these molecules is downward because of gravity, so water molecules are constantly moving upward toward greater depths. The more water there is in the world, the deeper it is likely to be found. The deepest known point on Earth is called Mauna Kea in Hawaii and it is 33,902 feet (10,350 m) below sea level.
The amount of pressure that exists at any given depth undersea is called the hydrostatic pressure. It is equal to 1 MPa (or 1000 kPa) at a depth of 1 meter below sea level, and it increases as you go down further. At a depth of 10 meters, the pressure is about 100 kilopascals (kPa), and it keeps increasing until you reach depths of about 6 miles (10 km). From then on, pressure decreases rather than increase because there is no longer any matter below this depth to pressurize.
With increasing ocean depth, pressure rises. At sea level, the air that surrounds us exerts a pressure of 14.7 pounds per square inch on our bodies. The higher the pressure of the water bearing down on you, the deeper you plunge under the sea. The pressure rises by one atmosphere for every 33 feet (10.06 meters) you descend. At a depth of 10,000 feet (3,048 m), the pressure is equal to that at Earth's surface.
At greater depths there is no way to tell how much water pressure is being exerted on you. If you were to go diving in these conditions, you would be operating under constant pressure!
The pressure of water on land is zero inches mercury. One hundred miles (160 kilometers) underwater it is estimated to be 1 ton per square inch (101.3 kilopascals). This is not enough to crush you like a soda can, but it is enough to cause some pain if you are exposed for too long.
At very deep levels the pressure increases so much that no organism can survive it. Even if you were able to get down to such depths, you could never come back up again!
The water pressure varies depending on what part of the world you are in, but it is usually less than one million pounds per square inch (14.7 megapascals) over most of the earth's surface.
This is due to a rise in hydrostatic pressure, which is the force per unit area that a liquid exerts on an item. At a depth of about 330 feet (100 m), the pressure is equal to that at sea level.
Hydrostatic pressure arises because submerged objects experience increased weight from the mass of the water they are immersed in. For example, if you were to drop a rock into a pond, it would create a small crater where it landed. The rock felt the effect of both atmospheric pressure and pond pressure, but since atmospheric pressure increases as you go downward while pond pressure decreases, the rock was pressed against its base by pond pressure at the bottom of the hole it created.
Atomic weights of elements are used to calculate how much pressure different substances will exert on you if you were to submerge them in water. Water contains two parts oxygen and one part hydrogen. Oxygen weighs 16 grams/mole while hydrogen weighs 1 gram/mole. Thus, water is composed of 80% oxygen and 20% hydrogen. If you added up the atomic weights of these elements, you would get 3 times the weight of hydrogen or 6 times the weight of oxygen. Since there are 2 atoms of oxygen for each atom of hydrogen, this means that oxygen is twice as heavy as hydrogen.
Pressure operates the same way in the ocean, except instead of simply a column of air above you, you also have the weight of all the water above you bearing down on your lungs. And water is far heavier than air. The pressure rises by one atmosphere for every ten meters under the surface. At the surface of the sea it is 14.7 kilopascals (kPa), but this drops rapidly with depth.
At any given point below the surface of the ocean, there is always some degree of turbulence. This means that there are small waves moving across the surface. If you were to go swimming at this point you would be swept away from the shore and out into deeper waters. However, if you waited until there was no longer any danger of being swept away then the turbulence should subside and you could swim without risk of drowning.
The pressure difference between the surface and the bottom of the ocean drives the wind and water currents. These currents can be very strong - up to 100 kilometers per hour (60 miles per hour) - so it is important not to try to swim against them!
The most significant current in the ocean is called the global ocean conveyor belt.
This vehicle enables scientists to monitor the deep oceans while subjected to extreme ocean pressure. At a depth of 10,929 feet (3,212 m), or about one-third of the way to the bottom of the Mariana Trench, the pressure is estimated to be about 1 million pounds per square inch (11.4 MPa).
At this depth, there is no light other than that which penetrates through the top few hundred feet of water. There is no air because all the oxygen has been consumed by living organisms. Water is squeezed out of the seaweed and other debris at these depths where it becomes liquid hydrogen at -452 degrees Fahrenheit (-268 degrees Celsius).
The vehicle itself is equipped with sensors that measure various parameters of temperature, pressure, and humidity in order to provide scientists with data about the deep oceans.
In addition to using sonar to map the seafloor, researchers have deployed radio transmitters into the water to track the movements of animals across large distances. These movements are used to estimate how long it would take an animal to travel from place to place, which is important in determining how long ago a species went extinct.