Puzzle 2: Alchemy

Alchemists spent centuries attempting chrysopoeia - the process of turning base metals, like lead, into gold.

Interest really took off after Aristotle popularised the idea that everything was formed of just four elements: earth, air, water, and fire. He believed that materials naturally strive for perfection and that gold was the perfect material. Other materials, such as lead, were seen as inferior and sick. So one had to simply find the appropriate cure and the result would be gold.

Now we know that lead and gold are unique elements and cannot be changed by chemical processes. It is however theoretically possible to turn lead into gold using a particle accelerator, but doing this with current technology would be incredibly expensive, only produce a tiny quantity, and be difficult to separate.

Scientific American: Fact or Fiction?: Lead Can Be Turned into Gold