A lava lamp, also known as an astro lamp, was a decorative novelty item invented in 1963. The lamp contains blobs of wax inside a glass vessel filled with clear or translucent liquid. The wax rises and falls as it changes density due to heating from an incandescent light bulb underneath the vessel. The lamp gets its name due to the fact that the wax resembles lava.
- Back to the Future Part II (In the Blast from the Past antique shop)