What you need:
- Plasma Ball (available at toy stores and online)
- Fluorescent Light Tube
- Wooden chair or stool to stand on (or anything not metal)
- Turn off the lights so that you can see the plasma ball glowing.
- Put your hand on the plasma ball. What happens?
- Now bring the fluorescent light tube close to the plasma ball. What happens?
- This step requires a friend, so have one close by and ready to help. Stand on the chair or stool and put your hand on the ball. Now have your friend hand you the light tube. Do you see it light up? What happens if your friend lets go? Be careful to not touch the ends of the light tube – it gets hot!
- Put a penny on the top of the plasma ball. Carefully touch the penny with another penny. Don’t use your finger – you’ll get a shock!
What’s going on?
The plasma ball is a miniature Tesla coil. Inside the ball is a coil of wires that have electrons going through them oscillating at a very high frequency. This shakes the atoms around the wires so hard that their electrons start to fall off! Inside the glass globe is a partial vacuum. This just means that some of the air has been sucked out. Because there is not as much air in there, it is easier to make electric sparks that can be seen.
The electrons then travel out into the air from the glass ball. We know this because the plasma ball lights up the light bulb. If you touch the plasma ball, all of the electrons will go through you to the ground. You see only one big spark inside the ball where you put your hand. If you stand on a stool, you are insulated from the ground and get filled with electrons. This means you can light up a fluorescent light bulb!
Download pdf version (with Teacher Notes)