http://www.smithsonianmag.com/arts-culture/The-History-of-the-Lava-Lamp-191900581.html
| Lava lamps consist of water and a special wax that is enclosed in a glass tube originally designed for soda. The glass lays atop a stand found in various colors. The wax actually isn't just wax, while the exact mixture is a trade secret, it primarily consists of oils, paraffin wax and carbon tetrachloride. This special wax has a specific gravity (density of wax divided by density of water) very close to that of water, heavier when cold, and lighter when heated. Also, since the wax has oil mixed in with it, it is very hydrophobic insuring the two fluids don't homogenize. The wax gives it that thick lumbering viscosity visually similar to that of lava. Underneath the lamp, a heating element for the wax is found, normally this is an incandescent bulb or halogen lamp. The combination of this hydrophobic wax and heating element create that wonderful slow moving lava-like liquid that we've all grown to love. |