What Am I Riddles

Question: I move faster in certain solids, but slower in certain gases. I am typically broken by objects with large masses. I can be used as for pleasure, practice, and even an alarm. If used excessively, I can cause harm. What am I?

Question: I know all, have seen all, yet I am not conscious. Looking back upon me shows mistakes and also good things. Looking in the middle of me shows opportunities to be exploited. Looking forward upon me shows the effects of decision. What am I?

Question: What smells better than it tastes?

Question: I'm a measurement of time.
But you'll find me on a map, not a clock.

What am I?

Question: I am around everything, everything that lives because of me. What am I?