Why would lightning, a flow of electrons, tend to strike neutral objects like trees, buildings, or the earth? (Does the word “induction” sound familiar? See page 15.)

Is the barn destined to be struck by lightning? Not if the owners have installed
lightning rods. Invented by Benjamin Franklin over 200 years ago, the system
makes use of pointed metal rods placed atop a building. The rods are “grounded.” That is, they are connected by thick wires to metal stakes buried in the ground. If lightning does strike, it will tend to hit the rods instead of the building and pass harmlessly into the earth. The pointed metal rods can also discharge a cloud before it has a chance to build up a charge big enough to cause a lightning strike.

Did this idea or inspiration, just “strike” Franklin out of the blue? Probably not. You see, Franklin is also credited with discovering that lightning is really electricity By flying a kite in a storm, he induced a flash of lightning to flow along the string to the earth. (DON’T even think of attempting this experiment! Franklin was very fortunate he wasn’t killed. Others trying to duplicate his findings were!) The idea for the lightning rod resulted from his kite-flying experiment.

Science is the search for knowledge. Using that knowledge to better our lives is called technology. In this case, Franklin discovered a new fact: lightning is electricity. He then devised a practical application for it: the lightning rod.

See if you can draw the charges on the top of the barn in the picture above. Hint: Look at the charges on the cloud and remember induction.

(See ^a  for the solution.)

Plenty of people knew that a charged comb would attract neutral objects. But only a few used that fact to filter air, paint cars better, and reproduce paper images.

Let
Inspiration
Strike
You

Design a machine that uses static electicity to perform a useful function. You now know the basics of static electricity. Just use the rules you discovered along with your imagination, and it should be a “snap.”