Come back ammonia, all is forgiven

It's Royal Society of Chemistry podcast time again. We're off to visit the compound that hair dye manfacturers delight in telling their customers isn't in a particular product. Because it's not the most beautiful of smells, reminiscent of the farmyard and animal houses at the zoo.

Yes, it's ammonia. Smelly - and yet it's a chemical that is made in vast quantities every year for fertiliser and other uses. Any idea where the name comes from? It's a back formation that links camel dung and the temple of an ancient Egyptian god. Which turns up in Chaucer. Take a listen...