Plasma Ball and Fluorescent Light Experiment

Materials

Here are the materials you will need for the experiment:

• Plasma ball
• Fluorescent light bulb (any type)

Steps for the Experiment

1. Turn on the plasma ball.
2. Bring the fluorescent bulb close to the plasma ball. As you near the plasma, the bulb will light up.
3. If you are using a long fluorescent stick, you can control how much of the bulb is lit using your hand. The portion of the bulb close to the plasma ball will remain lit, while the outer portion will stay dark. You can see evanescence or fading of the light as you pull the light further from the plasma ball.

How it Works

A plasma ball is a sealed glass containing low-pressure noble gases. A high voltage electrode sits in the center of the ball, connected to the power source. When the ball is turned on, electrical current ionizes the gas in the ball, creating plasma. When you touch the surface of the plasma ball, you can see the path of the plasma filaments running between the electrode and the insulating glass shell. Although you cannot see it, the high-frequency current extends beyond the surface of the ball. When you bring a fluorescent tube near the ball, the same energy excites the mercury atoms in the fluorescent bulb. The excited atoms emit ultraviolet light that is absorbed into the phosphor coating inside the fluorescent light, converting the ultraviolet light into visible light.