Theodore Gray

Gray Matter

The Instant Hot Tub

If a few ounces of quicklime mixed with water can make self-heating soup cans, we figured 500 pounds of it could create a self-heating hot tub

Self-heating soup sounds like something from the future: Push a button on the can, and three minutes later the contents are piping hot. But it’s widely available today, along with self-heating coffee and hot chocolate. In Japan, I even found self-heating sake. Pretty high-tech!

Or not. In fact, these products use a chemical reaction known since at least 4000 B.C.—the mixing of quicklime and water. When you roast limestone at about 1,650°F, it converts to quicklime, a powder used to disinfect corpses in war zones. Mix quicklime with water, and it grabs and binds the water molecules, releasing lots of energy in the form of heat. (The material left over, known as hydrated or slaked lime, is the basis of lime mortar, popular in the Roman empire and still used today.)

Soup is OK, but I decided to use the technology to make a self-heating hot tub.

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Gray Matter

Flaming Oxygen Drops

In large quantities, pure liquid oxygen is powerful enough to launch rockets. But even a tiny bit packs a wallop too

Oxygen is a good thing. Oxygen is life. But if it were much more than one fifth of our air, we’d be in serious trouble. The other four fifths is nitrogen, an almost completely inert, obstructionist gas whose main effect is to get in the way of the oxygen, especially where flame is involved. For every bit of oxygen a fire consumes, it has to heat up and push away four times as much useless nitrogen. With pure oxygen, that damper is gone, and things that merely smolder in plain air go up like dry tinder. In 1967 three Apollo 1 astronauts died in a raging fire when Velcro lit up in their pure-oxygen pressurized space capsule.

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Gray Matter

Trap Lightning in a Block

To create beautiful electrical-charge patterns like this, you could use a giant particle accelerator. But shag carpeting will also do just fine. Watch how Lichtenberg figures are made in our amazing video

There are many unusual things to see around Newton Falls, Ohio—the Wal-Mart with hitching posts for Amish buggies, the Army base with helicopters and tanks proudly arranged on hills—but I was here for the most unusual thing of all: the local Dynamitron. I was here to make frozen lightning.

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Fire Without Flame

Precious metals in your car burn up the dirty exhaust, with no flame to be seen

More Than Meets the Eye: Invisible propane gas flows, unlit, from a torch. On hitting the rhodium-studded ceramic honeycomb from a catalytic converter, it burns without flame, heating the ceramic red-hot. Photo by Mike Walker

To a chemist, burning means the rapid combination of a fuel with oxygen, called oxidation. You might say, for instance, “Oh, no, we didn’t have a fire at the nuclear power plant, we just had a ‘rapid oxidation event,’ ” a phrase that won officials at Three Mile Island the Doublespeak Award in 1979.

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Gray Matter

Plate Your 'Pod

How do you keep the back of your iPod clean? Sandpaper and electricity

by Mike Walker: Photo by Mike Walker
I think Apple sells fantastic objects that look like they came from the future. And apparently, in that future we all live in velvet rooms and have no fingers-there´s no other way to explain the ultra-shiny mirrored backside of my new iPod nano, which got scratched and grungy with fingerprints in exactly three seconds. So I gave it a nifty scuff shield and, while I was at it, my own logo, using a superthin layer of electroplated copper.

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Gray Matter

Burning Metal

Send steel up in flames—as long as it's in wool form

by Mike Walker: Hot Steel: Set a steel-wool pad ablaze using an ordinary match. Photo by Mike Walker
I was 10 years old, but I'll never forget that day: The smell of bread in the oven. The crunchy grit of steel wool in my fingers. The fact that my mom still left matches out where I could find them. That's when I learned that, yes, you can light steel with a match.

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Alive; Frozen Dead

Battery_on_ice

Our good friends at lifehacker spotted this suspicious tip for reviving a dead laptop battery over at Metacafe. According to the posted video, freezing the battery can help to rejuvenate it.

PopSci's Mr. Wizard-in-residence Theodore Gray weighs in:

I think it's pretty unlikely this has much effect one way or the other, and of course "dead" comes in different flavors.

I have a battery right now that was practically new and suddenly it's totally and completely dead, like it blew a fuse or something.  A freezer isn't going to make any difference for that problem.

But if it's just not holding its charge as long as it used to, as all such batteries eventually do after a year or so, then there is at least the theoretical possibility that freezing it might have an effect.

As fas as what I've read on battery technologies, though, I've never seen the freezing recommendation mentioned as a possible method for increasing the life of different battery systems."

Anyone had any luck with this personally? Let us know in the comments —Dave Prochnow

Revive A Dead Laptop Battery

Better Math Means Safer Bridges

Foundbridges
The recent bridge collapse in Minnesota happened in large part, people think, because the bridge was of a non-redundant design.  Which is to say that if certain elements of the bridge failed, there was no backup, and the whole bridge would fall.  Which it did.

We are told by the authorities that modern bridges are not built this way anymore, that they always have built-in redundancy.  But redundancy is expensive: You kind of have to build everything twice.  What if there were a better way?

Stephen Wolfram, with whom I co-founded the company that makes the Mathematica software, decided to take a look at the problem using the technique of experimental structure generation.  You can read about it in his blog post.

The idea is to use simple programs to generate vast numbers of possible bridge designs—say, different possible layouts of struts—and then run a simulation on each one to see how well it performs.  Some will be obviously stupid, some will be the same as current designs, but if you're lucky, maybe some of them will be better.  They might find a way to spread the effects of a failure in one place out over the whole structure, for example.

This type of exploratory search for designs is the ultimate form of thinking outside the box. The structure-generating program intentionally doesn't know anything about good bridge design: It's going to come up with things that make no sense whatsoever.  But experience in other fields shows that sometimes the completely ridiculous idea is the one that turns out to work. —Theodore Gray

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Uncovering a Natural (Magnetic) Attraction

A long walk on the right beach could reveal magnetite hiding in plain sight.

Dept.: Gray Matter
Element: Magnetite
Project: Collecting, purifying magnetite; making magnetic field lines
Cost: Free
Time: 30 minutes
Dabbler | | | | | Master




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