Logic Riddles

Question: You have 7 tennis balls that are all identical but one of them is slightly lighter than the others.

Using a balance scale and only two separate weightings, how can you find the light tennis ball?

Question: Little Johnny's teacher asks him, "If I gave you two cats, then two more, and two more cats; how many would you have?"

Little Johnny replies, "Seven!"

His teacher asks him again more slowly, "If I gave you two cats, then two more, and two more cats; how many would you have?"

But again Little Johnny replies, "Seven!"

Next she asks, "If I get two cats, then two more, and two more cats; how many would I have?"

Little Johnny replies, "Six!"

"Good Job Johnny! Now if I gave you two cats, then two more, and two more cats; how many would you have?"

Johnny thinks for a second, "Seven."

But Johnny is not wrong. Why?

Question: A robber tried to steal the crown jewels. He got caught by the King's guards and was taken to the king. The King was feeling generous that day and asked the robber how he wanted to die. A few minutes later the king let the robber go punished yet alive.

How did the robber want to die?

Question: A man has hundreds of bodies buried on his land, many of which are cops and criminals. Many people find out what he has been doing, but none go to the police.

Why not?

Question: I'm teary-eyed but never cry.
Silver-tongued, but never lie.
Double-winged, but never fly.
Air-cooled, but never dry.

What am I?