Chemists turn gold to purple -- on purpose: Color change confirms a new way to harvest energy from sunlight

Chemists turn gold to purple -- on purpose: Color change confirms a new way to harvest energy from sunlight
Professor Richard Watt and his chemistry students suspected that a common protein could potentially react with sunlight and harvest its energy -- similar to what chlorophyll does during photosynthesis.

The story of how they proved it sounds as colorful as the legend of the leprechaun who hid his pot of gold at the end of the rainbow.

They started with citric acid from oranges and mixed it with the protein. Next they dissolved gold powder into the solution. Then they put vials of the yellow-colored mixture in direct sunlight and crossed their fingers in the hope that it would turn purple.