Krulwich Wonders...
10:53 am
Mon March 11, 2013

Guy Builds Solar-Powered Death Ray In His Backyard (Yawn)

Originally published on Sat March 9, 2013 5:22 am

Aatish, a guy I follow on Twitter, tosses this stuff off like it's no biggie, but that's because he's a physics grad student. He knows things I don't know. And because I don't know them, what he finds mildly amusing makes me gasp. Really.

Here's an example. He mentions this video about a guy who gets an old TV screen, hauls it into his backyard, mounts it on a frame, does something physics-y — I'm not sure what — maybe he just tilts it at the right angle to the sun, and suddenly, with nothing added, the guy's got a homemade concentrated sunbeam producing a 2,000-degree Fahrenheit death ray in his yard (with his wife and kids standing right there) that melts a stack of coins into hot foam, blows the caps off bottles and turns solid concrete into glowing orange liquid.

You've got to see this ...

I was really curious to figure out how he did this, and, as it happens, there's a video that shows how. Grant Thompson, who hosts a YouTube channel called kingofrandom.com — that's him narrating — created this sun-scorcher from a part he found inside a 13-year-old Toshiba 50-inch flat screen TV. He read an ad from a lady who wanted to dump her old set, picked it up for free, moved it to his backyard, hacked it open, removing various layers of this and that until he found, deep inside, a large, flexible plastic sheet which, he says giddily, is a "giant virgin Fresnel lens."

I've never heard of Fresnel lenses, but the Defense Department might want to start buying old TVs, because they are powerful, powerful, powerful. Put them in the sunshine, and automatically they focus the sunshine on one spot. That spot gets very hot very quickly, as you see in the video. All Grant had to do was build a frame (he's made another video to explain how) to house the plastic sheet so he can aim it safely.

Because this is NPR, I'm sure there are lots of you out there who understand the physics of sunlight, and will probably not find this gizmo all that shocking or awesome. But it is. It just is. And to his credit, Aatish, the guy who tweeted about it, even though he's getting a Ph.D. in physics, wrote it up this way: "You can build a solar powered death ray in your backyard out of old TV parts. Goldfinger, take notes."

With those 20 words, he's saying exactly what I feel: "OMG!"

Which is why I follow Aatish.

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