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: A mirror for the famous, but informative to all.
I'll show you the world, but it may be a bit small.

What I am?

Question: Alone I am 24th, with a friend I am 20. Another friend and I am unclean.What am I?

Question: Thousands of orphans who lost their old home,
found by others who have lost their own.
To hide a secret that is obvious to all,
becomes even more obvious when the host falls.

What am I?

Question: You can easily touch me, but not see me.
You can throw me out, but not away.

What am I?