History of Lava Lamps
Lava Lamps (or Lava Lites) have been around longer than anyone can really remember. A man named Craven Walker saw a similar type lamp in a pub where he was drinking an ale. He described it as a “contraption made out of a cocktail shaker, old tins and things.”
Walker, being an inventor, was determined to make an even better version of the lamp and spent the next 10 years working on a better model (during this time he also ran a house-swap agency and made a film on nudism). Once Walker perfected the right combination of oil, wax, and other solids, he named the new lamp Astro. The original version had tiny lights at the bottom to simulate starlight. He made several different versions of it – the Astro Mini and the Astrao Coach lantern were two such versions. In 1964, he took the light to a trade show in Brussels to show it off.
At the trade show, a man named Adolph Wertheimer noticed the Astro lamp and thought it was really cool. He and his partner, Hy Spector, paid Walker for rights to sell the lamp in the United States. They built the lamps in Chicago (where they are still built today) and named the new lamp Lava Lite. A legend was born.
How a lava lamp works
How a lava lamp works is a bit of a secret but of course, Reeko knows no secrets when it comes to science so he’s going to tell all. The lamp consists of an incandescent bulb which heats the contents of a tapered glass bottle containing water and a clear mix of wax and carbon tetrachloride. A metal wire coil at the base of the lamp enhances the heat convection.
The wax is just slightly denser than the water and will float when the lamp is turned off. By adding a nonflammable solvent to the wax, the density is adjusted so it is very close to the density of the water. The wax is slightly denser than the water at room temperature (and will sink) and slightly less dense than the water under marginally warmer conditions (so it will float). The density is so close to that of water, that the floating effect occurs as the was reaches the bottom of the lamp and is heated by the light bulb. When the wax reaches the top and is further away from the lamp, it slowly cools and sinks back to the bottom. The temperature difference between the top of the lamp and the bottom only differs by a few degrees.
The lava lamp owes its classic shape to physics as much as aesthetics: at the tapered end there is more surface area per unit volume of liquid, hence the liquid in that area undergoes a higher rate of cooling than the liquid nearer the bottom. The whole process is a macroscopic, visible, form of convection heat transfer, although it also occurs on a molecular scale within the liquids themselves.