Theodore Gray

Gray Matter

Carve Steel with Saltwater, Electricity and a Tin Earring

Power sculpting with an old earring

I remember seeing a demonstration of a seemingly magic process at an engineering open house decades ago, in which a soft metal bit carved detailed shapes into far harder metals. It's called electrochemical machining (ECM), and it's so simple in principle that you can do it at home with a drill press, a battery charger and a pump for a garden fountain.

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Gray Matter

Frozen on Video: Theo Gray Sculpts in Solid Mercury, with Some Help from Liquid Nitrogen

How to cast solid, if fleeting, shapes in mercury: Just keep it at 320 degrees below zero

What you consider solid, liquid or gas depends entirely on where you live. For example, men from cold, cold Mars might build their houses out of ice. Women from Venus, where the average temperature is about 870°F, could bathe in liquid zinc.

We think mercury is a liquid metal, but it’s all relative. At one temperature, the mercury atoms arrange themselves into a solid crystal; at another, they flow freely around each other as a liquid. Children from Pluto (like mine, for example) could happily cast their toy soldiers out of mercury, because on that frigid planet it is a solid, malleable metal a lot like tin. Here on temperate Earth, you need a stove to cast tin, but a tank of liquid nitrogen to make mercury figurines.

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Wolfram Co-Founder On Why Wolfram|Alpha Doesn't Need to Kill Google

Gray Matter's own Theodore Gray reports from his day job at Wolfram on how his new "knowledge engine" provides exactly what Google can't

PopSci's Grouse recently reviewed Wolfram|Alpha. I guess that's what happens when you ignore your editors for a week: They let someone else write about your project!

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Gray Matter

Apple Juice

Charge your gadgets with a piece of fruit and some pocket change

Arthur C. Clarke wrote that "any sufficiently advanced technology is indistinguishable from magic," but he was wrong. It's easy to tell the difference -- technology works. For example, "remote-viewing" mentalists claim they can see events far away, yet they fail every test. In fact, remote viewing is simple: It’s called TV.

Another example that recently circulated online was a fake video of someone charging his iPhone by jamming the end of a USB cable into an onion. How do I know it was fake? First, you need contacts made of two different metals, and second, you can't get enough voltage out of a single vegetable. What makes the ruse so disappointing is that it is possible to charge an iPhone this way, if you do it right.

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Gray Matter

Bacon: the Other White Heat

You know bacon is delicious, but did you know it contains enough energy to melt metal?

I recently committed myself to the goal, before the weekend was out, of creating a device entirely from bacon and using it to cut a steel pan in half. My initial attempts were failures, but I knew success was within reach when I was able to ignite and melt the pan using seven beef sticks and a cucumber.

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The Really Dangerous Book for Boys

Introducing a new collection from PopSci's truly mad scientist

Without a doubt, the most fun thing I've worked on in my five-plus years at PopSci is the Gray Matter column. Nearly every month since mid-2002, contributor Theo Gray has come up with new ways to illuminate the world of elemental chemistry, often by setting things on fire. But far from your average YouTube-loitering pyromaniac, Gray combines sharp, lively writing with a gifted professor's knack for making the complex simple.

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Gray Matter

Blowing (Up) Hydrogen Bubbles

A dramatic demonstration -- with exclusive video! -- of why the same gas that heats your house can also make it explode

Living in the Midwest, where heating homes with propane is common, I periodically see reports in the local paper that yet another unoccupied house has exploded. They often note that the roof was found in the basement, while the walls were spread some distance into the neighboring fields.

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A PopSci Christmas: Holiday Lights and... Explosions (Of Course!)

Christmas chemistry show provides a chance for otherwise sensible faculty members to mix dangerous chemicals and light them in front of an audience

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Gray Matter

Homemade Titanium

With heat and common chemicals, the author turned ore into metal

An iron crowbar costs about $8; one made of titanium, $80. Solid-titanium scissors start at $700, and don't even ask about the titanium socket wrench. Titanium must be a rare and precious substance, right?

Actually, as raw ore, titanium is 100 times as abundant as copper. Nearly all white paint is white because of the titanium dioxide found in the ore. Something like four million tons a year go into paint, sunscreen, toothpaste, even paper.

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Gray Matter

Making Glass in a Grill [With Video!]

The author creates an ornament—using his barbecue

All the components of glass can be found in two places: the beach and the laundry room. It’s possible to melt pure white-silica beach sand into glass, but only at temperatures of 3,000 to 3,500°F. Washing soda, lime or borax (a traditional laundry aid) added to the sand disrupts the quartz-crystal structure of silica and reduces the required temperature to a more practical, though still dangerous, 2,000°F, which I achieved with a backyard grill and a vacuum cleaner.

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