Mysterious chemical drawings
Science draws with an invisible hand – discover how it’s done!
Warning! Only under adult supervision.
- watercolor paper;
- black-and-white image of a skull;
- solutions of copper sulfate;
- ammonium carbonate;
- potassium iodide;
- iron(II) sulfate and tannin;
- plastic skeleton;
- coffee filter.
Apply a copper sulfate solution to the eye sockets of a black-and-white image of a skull. Leave the image over a solution of ammonium carbonate – suddenly the skull’s eye sockets start turning blue!
Apply a solution of potassium iodide to watercolor paper. Dip a plastic skeleton’s feet in a copper sulfate solution. Now if this skeleton walks on the paper, it leaves dark footprints behind!
Use a tannin solution to draw an invisible skull on a coffee filter. Leave it in an iron(II) sulfate solution. The liquid starts rising to reveal the invisible skull!
Ammonium carbonate decomposes to release a gas called ammonia. These gas molecules bind to copper ions, yielding a new dark blue compound. Share the results with our teacher via the MEL Science app!
Copper sulfate can also react with potassium iodide. This time, it yields molecular iodine and a dark brown triiodide complex.
The antioxidant tannin possesses a lot of special fragments that can trap iron(II) ions. This creates a new compound with a dark violet color.
Ultimately, none of these images appeared on their own – they were drawn by the "invisible hand" of science!
Similar experiments are included in the “Chemistry for spies” set from the MEL Science subscription.