How-To: Trap lightning in a block


Science bad boy Theo Gray shows you how to create lightning bolts in a piece of acrylic. OK, so you need the juice of a five-million-volt particle accelerator to get the effect seen here (via the Kent State Neo Beam’s Dynamitron):

With the Dynamitron – rented for the day – adjusted to around three million volts, it blasts electrons about halfway through half-inch-thick pieces of acrylic sheet. The plastic is a very good insulator, so it traps the electrons inside. Coming out of the machine, the blocks don’t look any different, but they hold a hornet’s nest of electrons desperate to get out.

Left alone, the electrons will stay trapped for hours, but a knock with a sharp point opens a path for them to make a quick escape. Electrons gather from all parts of the block, joining up to form larger and larger streams of electric current on their way toward the exit point. As the charge leaves, it heats up and damages the plastic along the branching trails it follows, leaving a permanent trace of its path. If you could see inside a thundercloud in the nanoseconds before a bolt of lightning emerged, you would see the same kind of pattern. The bolt doesn’t just pop up fully formed; it has to gather charge from all over the cloud.

But he also explains how to create a more low-impact version in “7 Mad Science Experiments You Can Do At Home But Probably Shouldn’t,” an excerpt from his highly recommended book, Theo Gray’s Mad Science.

7 Mad Science Experiments You Can Do At Home But Probably Shouldn’t

In the Maker Shed:

Theo Gray’s Mad Science

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Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. His free weekly-ish maker tips newsletter can be found at

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