March 27, 2008

Lava Lamps

Stupid Question ™
Oct. 12, 2000
By John Ruch
© 2000

Q: What are the solid and the liquid inside a Lava lamp?

A: Haggerty Enterprises, the US makers of the “Lava brand motion lamp,” had a simple answer: It’s a secret.

The one thing they could tell me is that the contents are non-toxic—and even that seems hard to swallow.

The Lava lamp is an upright glass cylinder containing clear fluid through which a waxy, colored substance slowly rises and falls. This “lava” rises because a light bulb in the base heats it up (via a metal coil); at the top of the lamp it cools off and sinks.

Anybody can make a cheap version of a Lava lamp—just toss some colored mineral oil into alcohol. But sophisticated chemistry is needed to produce the Lava lamp’s hypnotic, random ooze.

The folks at Haggerty have spilled more beans to other journalists, saying that the lamp contains wax and “14 secret ingredients.” They’ve also admitted that the liquid is only partly water, and that the “lava” is basically colored paraffin wax.

This jibes with the US and UK patents (the British invented Lava as the Astro Lamp), which call for “lava” to be made of mineral oil, paraffin (both liquid and solid), a dye and carbon tetrachloride (a dry-cleaning solvent that probably makes the stuff a little more dense than water).

The US patent calls for the liquid to be about 70 percent water, and about 30 percent some other liquid that apparently increases the viscosity and the rate of heat transfer. The patent suggests propylene glycol, glycerol, ethylene glycol or polyethylene glycol. In layman’s terms, that’s solvent, laxative or antifreeze.

We know which one Haggerty uses, thanks to one of those bold souls without whom we never would’ve made it out of the caves: a 65-year-old Chicago man who, according to the June 1996 “Annals of Emergency Medicine,” drank the liquid in a Lava lamp. He suffered kidney failure.

Hospital analysis revealed the lamp contained polyethylene glycol, as well as chlorinated paraffin, “microcrystalline wax” and, surprisingly, kerosene (possibly used to thin the paraffin, and responsible for the fuel-like smell given off by broken lamps). So much for “non-toxic.” (Clearly, Haggerty is assuming you won’t chug an entire lamp.)

Of course, this doesn’t account for all 14 “secret ingredients.”

However, common problems with Lava lamps are fertile grounds for guesses. For example, all lamps eventually wear out, at which time the “lava” separates into two masses. One floats, and one sinks. This has led hobbyists to speculate that it contains some sort of powder in solutions, such as talc or silica, which eventually precipitates down into the bottom of the “lava” ball.

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