pressure groups

Question
I'm 12 and almost certified. But I don't uderstand pressure groups. How do you figure them out?

Answer
Hi Alyssa,

Most of the air you breathe is composed by nitrogen (79%). Your body is designed to release all of it quickly at 1 atm of pressure. However, the more pressure you add to the environment, the harder it is to release it quickly. Therefore, nitrogen is gradually stored inside your body. Because you cannot physically see nitrogen in your body, divers use letters to represent each of the stored nitrogen levels in your body. That is what we call "pressure groups". The farther out the letter in the alphabet, the more stored nitrogen you have, therefore the shorter your bottom time should be to avoid decompression illness.

I hope this short explanation helps you out. However, feel free to contact your instructor. I am sure he/she will be very glad to go over this with you. After all, we instructors know that this topic may take a little bit of time to fully understand... so he or she will understand your need.

Sincerely,

Gustavo E. Flores
PADI Open Water Scuba Instructor