Answer:
Deep, deep, do they go. Spreading out as they go. Never needing any air. They are sometimes as fine as hair.
I'm not a bird but I can fly through the sky. I'm not a river but I'm full of water.
I go in dry and come out wet. The longer I stay in, the stronger my surroundings get. What am I?
I am lighter than air, but a hundred people cannot lift me. Careful, I am fragile. What am I?
I always run but never walk often murmur but never talk have a bed but never sleep has a mouth but never eat.
I go in hard, come out soft. Blow me hard and I'll make a pop. What am I?