Science Fair Idea: How Lightning Rods Work


For today’s science fair idea, we go back 80 years to find this idea from the May 1937 issue of Popular Science. Junior can demonstrate how lightning rods protect a building from fire caused by lightning. If the teacher insists that Junior answer a question, then he can use the experiment to answer the question, “do lightning rods protect buildings from fire?” Hopefully, Junior will discover that they do. But in the process, he gets to set fire to a paper model of a house using high voltage electricity.

The pictures should be self-explanatory.  At the left, the spark is being applied directly to the model house, which quickly bursts into flame after the simulated lightning bolt strikes.  At right, the structure is protected by a lightning rod, which safely carries the current to ground.

To generate the spark, the magazine recommends a “neon-sign transformer or a spark coil.”  If you don’t have a spark generating device around the house, the Internet is full of plans.  If you’re in a hurry, you can just purchase this Tesla coil at Amazon, and get the best of both worlds.  Junior doesn’t have to build the coil, but he did build the lightning rod, so he did the work to prove his hypothesis.  As a bonus, he gets sparks, flames, and smoke.  The teacher will certainly be impressed, and Junior will come home with a blue ribbon.

The decorations on the house are a nice touch, but are optional.

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