Question

explain in word why you cannot breath thru a long (say 2m) snorkel

Answer 1

This problem has to do with the strength of our diaphragm muscle and the pressure of the water in the swimming pool.

If we look at the problem in reverse, we can understand it easily. People drink through straws all the time. But they can not drinke through a large pipe or straw.

When we get underwater, just a few meter of water is enough to put so much pressure around our chest that our diaphragm muscle cannot overcome it. our diaphragm muscle simply does not have the strength to inhale against the water pressure pressing on our chest.

It is interesting that elephants can snorkel in relatively deep water. The reason is because their lungs are completely unique among mammals.