Answer:
Teenage girls are pros at creating me. Learn me in classes.
When I point up, it's bright. When I point down, it's dark. What am I?
I always murmur but never talk. Always run but never walk. I have a bed but never sleep, have a mouth but never speak. What am I?
My teeth help me suck.
I am lighter than the material I am made of. You see parts of me but more of me is hidden underneath.
Give it food and it will live, give it water and it will die.