Invisible wax picture
Wax’s hydrophobic properties
What could be simpler than drawing an invisible picture?
Warning! Only under adult supervision.
- hot water;
- wax candle;
- watercolor paper;
- watercolor paints.
Put some candle wax in a glass and add hot water – the wax melts and floats to the surface. Dip a brush in the melted wax and use it to make an invisible painting on some watercolor paper. Now apply some watercolor paints to the paper – your hidden image appears!
Wax is mainly composed of fats and fatty acids, the molecules of which contain many groups of atoms consisting of carbon and hydrogen. Such groups don’t attract water molecules – in fact, they repel them. Therefore, water collects in droplets on the wax, either remaining on its surface or beading up and rolling off of it entirely. As watercolor paints mostly consist of water, they can’t permeate into the wax-covered sections of the paper, and your secret drawing is revealed instantly!
Cool experiments await you in the MEL Kids subscription!