How Lightsabers Work - Howstuffworks (article)
Important Safety Information
A lightsaber is not a toy! Keep it out of reach of children at all times. Lightsaber locks are required in most states.
There are two ends to any lightsaber -- one end has the belt ring, while the other end houses the blade arc tip and blade emitter. NEVER point the blade emitter of a lightsaber toward your own body. NEVER look down the "barrel" of a lightsaber, even if you are "sure" it is in safe mode. If you accidentally activate the lightsaber, serious injury could result.