Lightning is beautiful, dangerous, and mysterious. The same brilliant flashes that inspire poetry and paintings can cause city-wide power outages and raging forest fires. While the average lightning bolt is only about five kilometres long and the width of a finger, it heats the surrounding air to a temperature five times hotter than the surface of the Sun and produces enough energy to power a 100 watt light bulb for three months. Try this easy experiment to make your own miniature version of a lightning bolt.

MATERIALS

• Aluminum pie plate

• Ball-point pen

• Thumb tack

• Wool sock

• Piece of styrofoam

INSTRUCTIONS

1. Push the thumb tack up through the centre of the pie plate.

2. Push the end of the pen onto the tack. Secure it with glue if necessary.

3. Rub the styrofoam quickly with the wool sock.

4. Pick up the aluminum pie plate with the pen and put it down on top of the styrofoam. Be sure not to touch the pie plate with your hands.

5. Turn out the lights and slowly bring your finger close to the pie plate. You should hear, feel, and see a tiny spark.

WHAT IS HAPPENING?

As you rub the styrofoam, it steals electrons from the wool and becomes negatively charged. Because like charges repel (move apart) and opposite charges attract (move together), the excess electrons on the styrofoam repel the electrons on the pie plate and push them to the top edge of the plate. The pen acts as an insulator, preventing the built-up charge from moving through you to the ground until you are ready. When you bring your finger close to the edge of the plate, the repelled electrons jump across the gap and escape through your body, giving you a small shock. When you turn off the lights, you should be able to see (as well as hear and feel) the discharge..