The Physics of Scuba Diving

I scuba dived more than I should. I did everything from open-water dives to technical dives. There is a lot of science that goes into the process of putting a human underwater. Scuba diving can teach us a lot about physics.

There is pressure.

Tank pressure is perhaps the first thing a scuba diver thinks of when dealing with pressure. The amount of air left in a tank can be determined by a pressure gauge. A full tank has a pressure of 3000 lbs per square inch. You should be out of the water if you get less than 200psi.

Nitrogen is the main component of normal air, making up about 80% of it. Oxygen is 21 percent of the total. We can imagine that the molecule are moving in different directions. Some of the molecule would bounce off of the wall if it was in a container. Each molecule exerts a small force on the wall. A bigger wall or container will cause more accidents.

The force per unit area is one of the ways we describe the motion of gas. The pressure of the gas is shown.

You get pressure in pounds per square inch if you measure the force in pounds and the area in squares. The most common unit for tank pressure in the US is that.

The bar is the same as the other units, with 1 bar being equal to 14.2 pounds per square inch. The pressure of air on Earth is very close to the value of one bar. The pressure of the air in front of you is likely to be close to 14psi. I don't want to judge you. If you are reading this from the top of Mount Everest, there is less air above you than there is on the ground. Send me a photo if that's the case. It is equal to 100,000 newton per square meter.

The water is made of tiny moving Molecules that act like balls and produce Pressure. The volume of air is the same as the amount of water. Going deeper in water increases the pressure because gravity pulls downward on the molecule of water. The pressure goes up by 1 bar for every 10 meters. The air pressure at Earth's surface is less than the water pressure on a dive 20 meters below sea level.

The ocean's water cannot collapse into a thin layer because of the increased pressure. The water under the surface pushes up more than the water below it. The water level remains constant because of this difference.

It's not that bad, even though it sounds like it's too much for a person to handle. Human bodies are able to adapt to change. If you've been to the bottom of a swimming pool, you know what the problem is. If the pressure on the outside of your ear is greater than the pressure on the inside of your ear, it can hurt. If you put air into your middle ear by pinching your nose closed while blowing air out of it, it will force air into it. If you have more air in the ear, the pressure on both sides will be the same. It is called equalization.

You need to equalize the air space in your scuba mask. As you go deeper, make sure to add air to it.

A diver could make a physics error. If you hold your breath you can create an enclosed air space in your lungs. If you hold your breath at a depth of 20 meters, you can move up to a depth of 10 meters. If you have the same lung volume and amount of air, the pressure in your lungs won't change. The water pressure outside of them won't go up. As a result of the reduced pressure on your lungs, they are over inflated. This can cause tears in lung tissue or force air into the bloodstream, which is bad.

There is optimism.

There are other problems to deal with when you are submerged. It is useful to sink rather than float if you want to stay submerged. I don't believe anyone would want to go to such depths. It's nice to be able to float. Scuba divers can change their floatiness for a variety of situations. This is called controlling the water.

The downward- pulling force is greater than the upward- pushing force. The object will not rise or fall if the two forces are equal. It's similar to hovering, but in water, and it's what you want to do when you scuba dive.

The water is neutral. Water floats. If you have a volume of water that is 1 meter on a side, and it is in the middle of more water, what would you do? The upward and downward force of the water must be the same.

Put a rock of the same shape and size in its place. The cube of water has the same buoyancy as this rock because of the interaction between the object and the water around it. The force on it will be downward since it has a larger mass than the water.

It is possible to say that the weight of the water is equal to the weight of the object. The mass per unit-volume of water is important. The density is what we're calling it. The symbol is used by physicists for density.

The weight of the displaced water is dependent on the density of water and the gravity.

The density affects the object's weight. If the density of that object is less than water, it will float. Wood has a lower density than water. The air inside a metal boat makes it less dense than water. Small rocks, gravy, and cider could float. I will not judge you if you know that quote. An iron nail is denser than water, so it will sink.

We now know how a scuba diver can keep their balance. Your density will decrease if you increase your volume. You will rise if this increases your force. You will sink if you reduce your volume. Breathing can change your volume underwater. Your lungs will expand when you breathe from a scuba regulator. It does not work the same way as expelling.

A device is worn by scuba divers to change their volume. A buoyancy control device is a bag that you wear on your back. It connects to a scuba tank so that you can change your position in the water.

There is thermal conductivity.

It feels good to have a temperature of 72 degrees. Have you been in the same body of water? That stuff is really cold. The difference is how quickly thermal energy transfers from your body to something else. It is the rate at which thermal energy can be transferred between objects. It goes from your body to the cold water.

If you have a wood block and a metal block sitting at room temperature, they aren't in direct sunshine or sitting on a heating device. The wood will feel warmer than the metal if you touch it. Wood has a lower thermal conductivity than metal. If you touch the metal with your hand, it will make you feel cold.

It's the same thing with scuba diving. The rate at which thermal energy moves from your body to the water is quicker than the same process in the air. It's possible to lose energy so quickly that it's possible to lose your core body temperature, which can cause problems such as respiratory and heart failure.

The most common solution to the water problem is to wear a wetsuit, which is made of a material with a very low thermal conductivity. The human body loses thermal energy. It's called a wetsuit because your body warms up when you're wet.

If you don't like being exposed to water, you could get a dry suit, which has waterproof seals on the wrists and neck, and built in boots, so that water doesn't get in at all. There may be a few small leaks. An additional task for the diver is added by this. As you descend to greater water pressures, the air inside the suit will decrease in volume, causing a Shrink-wrap effect on the body, so that there is no room for your arms and legs. You can add air to the suit at deeper depths, but you have to let the air out when you return to the surface.

There is underwater vision.

I've been on some dives where I couldn't see a thing. It was not very enjoyable. The purpose of diving is to see things underwater. You need a mask in order to see things. The air space between your eyes and the water is created by the mask. Humans are meant to be on land and not in water.

A lens bends light based on its shape and the speed of light outside it. The speed of light in a material can be described. The speed of light in water is less than the speed of light in air. It makes the lens in your eye not be able to bend the light to focus on you. Blurry vision is the result.

When you wear a mask, the air in front of your eyes allows your lens to bend the light in the right way. Light travels through the water at a slower rate than it does through air. Light bends when it goes from one medium to another. It can make things look closer than they really are.

What does this do? Light reflects off objects and into our eyes. On your diving trip, take the example of a fish you see. Light bounces off the fish and travels through the water and into the air in the scuba mask. Light rays bend because of the difference between air and water. We don't know that the light changed direction. They assume that it traveled in a straight line. It looks like the light came from a spot that is close to the fish.

The diagram should help.

It's not easy to see fish and coral underwater. We like to think that water is transparent. Light will be absorbed if you have pure water. The light will be gone after 300 meters. It would be as dark as night at a depth of 300 meters. It's not a good idea to be scuba diving that deep.

It's not the same for all colors. After 5 meters of water, almost all red light will be lost. You will only see blue light when you go deeper. Fish and coral will appear to be dark gray without red light.

If you bring a flashlight, you can fix this problem. You can still see the red parts of the fish even though the light from your flashlight does not have to travel as far as light from the surface.

There is partial pressure of gases.

The mixture of nitrogen and oxygen in the air is usually 81 percent and 21 percent, respectively. Oxygen and nitrogen interact differently with the body. The idea of partial pressure can be used to deal with gas mixture. Oxygen at a pressure of 0.21 ATM and Nitrogen at 0.79 ATM are the same as air at 1 ATM.

The body is impacted by both of these gases. The partial pressure of oxygen is sometimes called PPO 2. Oxygen is needed by people but not too much. The air pressure is lower in the plane you are in. It is not enough oxygen for your brain to function if you have a PPO 2 below 0.17. You might pass out if you can't think straight. People have to wear supplemental oxygen masks on high altitude aircraft if they don't have pressurized cabins. In the event of a decrease in cabin pressure, flight attendants in airliners go over safety procedures.

The problem is likely to be under the water. People can have convulsions if the partial pressure of oxygen gets high.

How do you get a high one? If you have a tank with pure oxygen and no Nitrogen, you can dive to a depth of 10 meters. If the ambient pressure is less than the pressure delivered to your lungs, you won't be able to breathe. The pure oxygen will be at two ATMs. You get one ATM of pressure for every 10 meters. The PPO 2 of 2.0 is greater than the ATM. Don't do that

Scuba divers don't use pure oxygen and instead use normal air that's 21 percent oxygen. The PPO 2 is not likely to cause problems. Regular air can be pumped into tanks. Oxygen tanks and compressions are things you see in hospitals.

If you put a mix of gas in your tank, what do you think it will look like? 40 percent oxygen and 60 percent nitrogen. It's called Nitrox and it's real. The ratio of oxygen to nitrogen is increased. If you breathe this gas at a depth of 20 meters, the oxygen would be at a rate of 0.4 3 ATM, which is 1.2 ATM. This gas mixture is close to a PPM of 1.6 ATM, so perhaps you shouldn't go any deeper than that.

If you can't go as deep, why add more oxygen to your tank? Oxygen increases the amount of nitrogen. Nitrogen gas can be absorbed by your tissues. Nitrogen comes out of your tissues when you go to a lower pressure. If nitrogen comes out too quickly, it will cause serious medical problems. Decompression sickness is also known as the bends. Your tissues absorb less nitrogen if you use less nitrogen.

Decompression sickness can be prevented by moving to the deeper depths very slowly. The goal for recreational dives is to only absorb a small amount of nitrogen that can be outgassed in the time it takes to return to the surface.

The calculation for the time you can stay at a certain depth depends on rough estimates of the average human body. Modern scuba divers use computers that calculate the time they have remaining based on the depth and time.

It's not enough for you to go on a scuba dive, but it will give you a sense of what's happening. If you want to try it out, an instructor at a scuba shop can help. Don't forget to have a flashlight.