Lavalamp

The principle of a lava lamp is very simple. Inside the lamp there is a vessel, or rather a cylinder, under which a light bulb is attached. Inside the cylinder are two insoluble substances, such as wax and a saline solution.
When the light bulb is switched on, the wax is heated and therefore also liquid. Now it`s about the effect that so fascinates all buyers of such a lamp.
Due to thermal expansion, the density of both substances decreases, but this happens because of the thermal expansion coefficient, with wax faster than with the other substance.
If the density of the wax decreases in contrast to the other substance, it becomes lighter and begins to rise in the cylinder in the form of bubbles.
In the upper part of the cylinder, the density of the wax increases again as it cools, and the whole effect is reversed.
The wax sinks back down and the cycle begins again.
Lava lamps were particularly popular in the 1970`s and were a must as a piece of furniture and can even be found almost everywhere again today.
The contents of these lamps and the substances they contain are harmful to health and for this reason you should always dispose of your lava lamp properly.