Static electricity: kids dig it. If I had a dollar for every time some youngster scooted their stocking feet across the carpet and zapped me with static, I’d be rich enough to afford those fancy dijon catsups the Barenaked Ladies sang about. We present this Demo Science science demo as a way for you to help the little goobers in your classroom a better understanding of how static electricity works—the positive and negative charges that give it its, um, charge.
Fun fact: The electricity in these goofy gizmos is also of the static variety.
The Least Dangerous “Water & Electricity” Experiment You’ll Ever See
It’s probably a good idea to preface this experiment by telling the smelly buggers you’re teaching that water and electricity do not and should not mix. Remind them that, most of the time, combining water and electricity is usually a one-way ticket to Deadsville. With that out of the way, you can continue on with a clear conscience. Gather your students ‘round and begin.
All you need for this science demo is a comb, a faucet, and hair. Step one: turn on the faucet so it provides a thin but steady stream of water. Step two: Run the comb through your hair about 30 times or for roughly 30 seconds (should be about the same either way). Step three: hold the comb near the running water without actually touching the water—if comb and water do meet, everything will be ruined and you’ll have to start over in shame and disgrace. Step four (and this is crucial): observe!
If you did it right, the stream of water will “bend” toward your comb on its trip south from the faucet to the drain. The closer the comb gets to the water, the more the stream will curve.
Science or Sorcery?
Combing your hair charged it with static electric charges, which, in turn, caused the comb to gain a negative charge. Water, in its natural state, is positively charged. And, in the scienciest part of all, opposite charges tend to attract—ergo, the positive charge in the flow of water bent toward the comb’s negative charge.
What your students may or may not know is that static electricity—just like that demonstrated here, but on a much larger scale—is essentially the cause of lightning in our atmosphere. Massive negative charges can build up along the bottom of storm clouds as they form. These charges are attracted to the even more massive positive charges of the Earth’s surface. Once these two opposites become big enough, the negative charges will “jump” to the ground in the form of lightning bolts.
Photo credit: praline3001 / Foter.com / CC BY-NC