Patented in 1968, this groovy lighting fixture is pure liquid motion created by matching the density of two insoluble ingredients.
Liquid motion lamps were invented in the U.K. The story goes that Edward Craven Walker, leader of a World War II Royal Air Force squadron and a nudist filmmaker, drew inspiration for the groovy lamp from a pub’s egg timer. The patent literature suggests that there is some truth to that tale. Walker was certainly the first to commercialize the lamps, which went on to embody the “Age of Aquarius.”
Those early patents aren’t easy-to-follow recipes, but they do discuss how the kitschy lamps work. The shapely vessel houses two main ingredients that are mutually insoluble. The key to the lamp’s ever-changing serpentine flow is to closely match the density of the two layers. A heat source tweaks the density of one component so that when warm, it is less dense than the other component and so floats to the top. Upon cooling, it is denser than the other component and sinks to the bottom.
Visit “What’s That Stuff” to read more about the chemistry of lava lamps.
Excerpted with permission, Chemical & Engineering News
Copyright © 2008 American Chemical Society