A Shocking Anniversary

According to fellow scientist, Joseph Priestly, Ben Franklin performed his famous kite experiment in June 1752. Franklin had been interested in “electric fire” for quite a while and had an on-going dialogue with other scientists of his day about the phenomenon. His famous key experiment established that lightning was a form of electricity.

There are a couple of myths about this famous experiment though. First, the kite experiment did not help Franklin “discover” electricity. Humans had known about electrical forces for more than a millennium. What it did do was establish the connection between electricity and lightning, and it ultimately led to Franklin’s refinement of the of the lightning rod. These devices are still used today on taller buildings to help channel the electric charge from a lightning bolt safely to the ground.

Also, neither Franklin nor the kite were actually struck by lightning. (He likely would have died if either had happened!) The wet hemp string that he attached to the kite was a good conductor of electricity, and they key attached to the string picked up electrical charge from the air in the active storm.

While we would not recommend that you replicate Franklin’s experiment, there are some easy ways to investigate static electricity at home and remember Franklin’s contributions to STEM.

Static Electricity Race

You’ll need: two aluminum cans, some masking tape, and two balloons.

Here’s what you do:

  • Using masking tape, mark a “start” and a “finish” line on the floor about 1 yard (1 meter) apart.
  • Place 2 empty soft drink cans on their sides on the starting line.
  • Inflate and tie-off 2 balloons. To charge the balloons, rub them rapidly back and forth on your clothing for a minute.
  • When you’re ready for the race, hold the balloons near the cans, without touching them to the cans, and have someone say “go.”
  • Each person tries to move his/her can across the finish line using only the static electricity of the balloon. Don’t touch the balloons to the cans!
  • After the race, ask participants what caused the balloons to move? (Static electricity – charged particles you rubbed off your clothes and onto the balloon.) Then ask if they can identify whether the part of the can nearest the balloon had similar or opposite charges. How could they tell? (Opposite charges attract. Like charges repel.)

Have fun!

Be sure to check out more from Family Science & Engineering guidebook for more ideas to inspire engineering exploration!