Why are you supposed to exhale when diving underwater?

Answers:

What gear is good for high school swimming?

Exhaling before attempting to descend underwater is simply a matter of allowing the body to displace less water (your chest area will be smaller), thus resulting in a negative state of buoyancy, and you sink.
Try this to see for yourself. Next time you are in a pool, go to the deep end. Take a deep breath and do not move. Then slowly start to exhale. You will start to descend. The more air you exhale, the more you will find yourself going underwater. Of course only do this if you are comfortable in the water, and can recover from an out of breath state.
Hope this answers your question?!?!

Whats a **?

keeps water from going up your nose.

Can/Should you swim with contact lenses?

your not suppoes to cuz then u cant breath unless u have a snurkal sum like dat.

May I tell you something?

To prevent your lungs from over expanding when you ascend

Is it generally allowed to wear a T-shirt to an (indoor public) pool?

lol
because if you inhale - water will enter your lungs - simple

Can you tell me if wednesbury swimming baths is open on bank holiday monday?

not to drown. duh!

George mens suits?

so that when you raise your head to take a breath, you don't waste time exhaling extra air