Why do scuba divers need to come back to the surface slow? if they come up fast what will happen?

Question

Why do scuba divers need to come back to the surface slow? if they come up fast what will happen?

Answer 1

If you are breathing compressed air, it is not pure oxygen but includes other gasses as well, including nitrogen. As you go down, the water compresses everything, including your lungs and the gasses in them. Under normal air pressure your blood absorbs very little, if any, nitrogen. But under the weight of all that water above you when scuba diving, the nitrogen is much more easily absorbed into your blood.

So, after being under water for a while your blood has absorbed quite a bit of nitrogen. This is kind of like the carbon dioxide in a bottle of soda-pop. As the scuba diver ascends, its like taking the lid off the soda-pop. At normal surface pressure the blood doesn't hold the absorbed nitrogen well, so it, just like the soda, fizzes. This can be very bad for the scuba diver causing gas-embolism or the bends. Painful, potentially fatal.

By ascending slowly, the scuba diver allows the nitrogen to 'off gas' very slowly and mostly through the lungs, so that the chances for anything bad happening is greatly reduced. A rapid 'panic' ascent is very dangerous! Slow ascents are safe ascents.

Answer 2

cause they have to decompress, every 10m a diver goes down, pressure doubles, you have to get used to the different pressures... it hurts your ears like h**l if you come up to fast, even from 10m

kind of like in a plane taking off, your ears hurt because of the imbalance of pressure.... once your up there you get used to it

Answer 3

The bends. The nitrogen in the blood expands and can cause death.