How to make a lava lamp with your own hands

The story of lava lamps began in the 1960s when a simple accountant Edward Craven Walker filed a patent application for a lighting fixture with an exciting visual effect. Walker's original recipe included tinted water and a mixture of clear oil with translucent paraffin and tetrachloromethane.

Pour in water. 2/3 cups will be enough. For experience, it is important to choose a beautiful bottle. It is fortunate that in the most beautiful bottles vegetable oil is often sold, which will also be needed for experience.

In 1970, carbon tetrachloride was recognized as a toxic substance and removed from the composition, so the recipe had to be changed. Paraffin does not mix with water. Usually its density is much lower than the density of water, but the addition of carbon tetrachloride makes it a little heavier than H2O, causing it to sink to the bottom. The lamp housing is a transparent vessel with an incandescent lamp at the bottom.

Fill the jar with oil. In order for the oil to flow smoothly into the vessel and not mix with water, tilt the bottle and pour oil on the wall. If the components nevertheless mix, it’s not scary: in a couple of minutes the water will still sink to the bottom.

Sinking down, the paraffin heats up from the lamp. Under conditions of increasing temperature, it expands faster than water, that is, it becomes less dense, which is why it rises up in the form of beautiful bubbles. Moving away from the lamp, the paraffin cools, and, as soon as they reach the top of the vessel, the bubbles again smoothly fall down.

A “kitchen” version of a lava lamp can be built in minutes. In it, the ingredients are interchanged: a transparent vessel fills the vegetable oil, and a denser colored water falls down. Water and oil, as you know, do not mix with each other.

Add dye. A pre-diluted dye in water is added to the vessel dropwise from a pipette. This is done simply for entertainment: droplets of perfectly round shape majestically fall through the oil and settle on the surface of the water. And last - add gas. Throw a pill or two vitamins into the vessel and enjoy the show: first, transparent water bubbles will start to rise from the bottom, then they will turn colored in the chosen color and spin in a fancy three-dimensional dance. This experience is very grateful for the experiments. Try different colors and shapes of bottles, add different amounts of effervescent vitamin and watch the drama of the lava show change. The resulting device is characterized by absolute reliability and can work properly for several weeks.

To start the show, it is enough to throw a colorless effervescent tablet, for example, soluble vitamin C. Such tablets contain acidic substances, carbonates or bicarbonates, which, when reacted with water, emit carbon dioxide. Bubbles of gas rise through the oil, taking with them part of the tinted water. Along the way, the bubbles meet and combine into larger droplets. Having reached the top, the gas escapes into the air, and a water drop gradually drops down. It remains only to illuminate the vessel with a flashlight at the back or bottom.

The article “Cold Lava” was published in the journal Popular Mechanics (No. 5, May 2013).