Light up a fluorescent tube using static electricity.

Safety

Be careful with the fragile fluorescent lights bulbs or tubes in the dark. Make sure you have shoes on.

You will need

  • fluorescent light bulb or tube
  • balloon
  • full head of hair.

What to do

  1. Fluorescent light

    Darken the room.
  2. Hold the fluorescent bulb in one hand and the balloon in the other. Rub the balloon vigorously on your hair.
  3. Bring the balloon near the bulb and watch what happens.
  4. Move the balloon up and down the bulb without touching the bulb.
  5. Move the balloon slowly toward the glass until it almost touches and see if you can get a spark to jump.

What's happening

An electron is a particle of an atom with a negative electrical charge. Electrons orbit the nucleus of an atom. The flow of electrons produces electricity. Electrons are relatively free to jump from one atom to the next, and they are attracted to some materials more than others.

When you rub a balloon on your hair, electrons from your hair jump over to the balloon.

A fluorescent bulb is a type of light that uses electricity to excite mercury vapor contained inside the bulb. The result is short-wave ultraviolet light. This light then causes the white coating on the inside of the light, which is made up of phosphors, to fluoresce producing visible light. Phosphors are substances that give off visible light when exposed to light or radiation.

Bringing a negatively charged balloon near a fluorescent tube excites the electrons in the mercury vapour. This also happens when you connect the bulb to an electrical current. Electrons in the mercury move to higher energy orbits and when they drop back down to their normal orbit they give off energy. This energy is in the form of ultraviolet light and cause the phosphors (white coating) to glow. When a spark jumps, you get a big release of energy and a correspondingly brighter glow.

Applications

A fluorescent bulb is more efficient than a regular (incandescent) light bulb because they use less electricity to produce the same amount of light.

The basic idea behind regular light bulbs is simple:

  • Electricity runs through the filament.
  • The filament resists the electricity, and this resistance turns electrical energy into heat.
  • The heat is enough to make the filament white hot, and the "white" part is light.
  • The filament glows because of the heat.

The problem is that heat wastes a lot of electricity. Heat is not light, and the purpose of the light bulb is light, so all of the energy spent creating heat is a waste. A fluorescent bulb produces less heat, so it is much more efficient.

It's a good idea to buy energy efficient light bulbs for your entire house. They can save you money on your electricity bill, they produce just as much light as standard bulbs and they last longer and don't have to be replaced as often as standard bulbs.

Phosphors are used in many other items, including regular TVs and plasma screens.

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