Electrostatics: The Shocking Truth
The 3rd and 4th grade students continued their unit on electricity today as we talked about the fundamentals of static electricity and its role in everyday life. Remember that static electricity is caused by the build-up of unbalanced charges (lightning, socks tumbling in the hot dryer, shuffling across carpets in wool socks in winter) that release a spark when they return to a neutral or ground state. The unbalanced charges occur with electrons get pulled away from the atoms of one surface and moved to another surface, giving it a negative charge.
A day of pouring rain couldn’t stop us from having fun with static! We used charged balloons to explore some of the properties of static electricity. The students went around the room finding surfacing their charged balloons would and would not stick to. They learned that this had to do with whether the surface was a conductor or an insulator. Then they got to use static electricity to perform some cool tricks, like pulling an empty soda can across the table and separating pepper flakes from salt. The pepper flakes jumped up to the charged balloon like iron filings to a magnet! The students couldn’t get enough of these awesome demonstrations of static electricity.
With the remaining time we demonstrated a Wimshurst machine for the students, which really “sparked” their interest. When enough of a charge built up on the metal probes the students could actually see the electrons jump to the other nearby probe in the form of a spark!
Additional Information:
What exactly is a Wimshurt machine? http://en.wikipedia.org/wiki/Wimshurst_machine
For more information on lightning research and safety information, check out NOAA’s National Severe Storms Laboratory:
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