It is easy to think of lightning simply as a bolt of electricity zinging out of a cloud, zapping the earth and vanishing in a clap of thunder. The reality is a bit more complicated--in fact, so complicated that scientists still cannot agree on how (or why) the process begins. What they do know is that in the U.S. alone, 86 people a year die from lightning strikes.
Instructions
1. Find a cumulonimbus cloud that is electrically charged. You need a ready-made one, because no one knows yet what causes the charge, only that it comes from a mixture of ice and water in the cloud. The top of the cloud contains a positive charge, and the bottom contains a negative charge.
2. Remember that the ideal spot for a lightening strike is the highest point in the area. The negative charge from the cloud creates a positive charge on the earth. When the electrical field's potential reaches about 10,000 volts per centimeter, there will be a narrow path in which ionization occurs.
3. Watch as the electrical field increases and a high-current leader ascends to meet a descending, or "stepped," leader. This causes a bolt of lightning (an electrical discharge) between the ground and the cloud. A number of strikes comprise flashes of lightning before the leader bolt, the process taking approximately 1/4 of a second from start to finish.
4. Study the path of the "stepped" lightning. As it leaves the clouds, the negatively charged current stops every few microseconds to search for an object to strike. This continues until it reaches the nearest positively charged object, which has begun sending up a leader to meet it.
5. Listen for the thunderclap as the negative and positive ions are pulled away from each other, flowing in opposite directions. This happens when the electrical discharge develops superheated discharge channels, and the rapidly expanding air produces a shock wave known as thunder.
Tags: electrical discharge, electrical field, negative charge, positive charge