Final answer:
A lava lamp works by heating up wax which becomes less dense and rises, cools down, then sinks, creating a captivating display due to incandescence and convective heat transfer.
Step-by-step explanation:
How a Lava Lamp Works
A lava lamp operates on the principle of incandescence and density changes. It consists of a glass bottle containing a special colored wax mixture and a clear or colored liquid. When the lamp is turned on, a heat source at the bottom warms the wax. As the wax heats up, it becomes less dense than the liquid surrounding it, causing it to rise. When it reaches the top, away from the heat source, it cools down, becomes denser, and sinks back to the bottom, creating a looping effect. This ongoing process results in the mesmerizing rising and falling motion characteristic of a lava lamp. Fluorescent light may also be looked at for comparison, where electrical current excites mercury vapor, which emits ultraviolet light that then causes a phosphor coating to glow. However, the heat-generated light and motion seen in lava lamps are entirely due to incandescence and the convective heat transfer that changes the wax's density.