A conversation with a 7 year old boy

Boy sitting in bath after washing his hair (rinsing it by diving under the water for 30 sec.)
Boy: Mom, what do people with glasses do when they go under water?
Mom: They take off they're glasses.
Boy: What if they need to see under the water?
Mom: Well I guess they just close their eyes and don't see.
Boy: Well, what if they are jumping in and swimming with sharks? They NEED to see to do that, like at Catalina, those cliffs...
Mom: I don't know then...