If I were to set my chair on top of my desk, it would be dangerous, as well as inconvenient. If I were to sit in my chair while it was set on my desk, it would be inconvenient and even more dangerous.

JONNY NELSON: Energy. There are lots of different types and lots of different ways of storing it. Chemical energy in a sparkler, elastic potential energy that fires a toy into the air, and many, many ...