+386 (0)1 300 6 888
Trubarjeva 39, 1000 Ljubljana

How to make a silver-coloured egg

To make a silver-coloured egg, you will need a hard-boiled egg, a candle and a glass half-filled with water. The glass should be large enough to fit the egg inside. Take the egg from the water and wipe it completely dry. Now ask an adult helper to assist you by taking a small candle and lighting it. They should then hold the egg with two fingers, one at the top and one at the bottom of the egg. Hold it in a horizontal position and bring it close to the flame of the candle. Once the egg just touches the flame, black patches will appear on the shell. The spots consist of black soot, i.e. small flecks of ashes produced when the wax burns.


Take care not to burn yourself on the flame and cover the egg with soot as carefully as possible. There! The egg in your hand is covered in soot. Be careful not to touch your clothing or you will get dirty very quickly. Now immerse the soot-covered egg into the glass of water. What do you see?

It seems as if the egg has become silver underwater. But did the soot really turn to silver? Of course not! Once you take the egg out of the water, it will once again be covered in soot. 

So what happened?

The soot lies on the egg in overlapping layers. That makes egg’s surface very “creased”. Since soot flecks are very small, the “creases” are also very small and hard to see with the naked eye. When the egg is immersed, tiny air bubbles get trapped between these creases, and stay there even after the egg has been completely submerged. A thin layer of air is thus created between the soot and the water.

When the soot-covered egg is immersed in water, a film of air develops between the egg and the water. The submerged part of the egg appears silver because the line between the water and the air gives the egg a mirror-like surface. It reflects light from the environment, making it seem as though part of the egg has turned silver.

individual visits
group visits
© 2014 Hiša eksperimentov