Tracing History

The history of science is filled with many happy accidents. Saccharin, the first artificial sweetener, was discovered when a chemist forgot to wash his hands and noticed that everything tasted weirdly sweet. During clinical trials for a heart medication, researchers noticed that their drug did absolutely nothing for heart conditions, but instead gave the male patients erections – thus Viagra was born. Super glue, LSD, microwaves – these inventions were all made with completely different intentions for their use, and yet now they’re common household items (except maybe LSD).

It won’t be a surprise, then, to note that many Nobel Prize-winning ideas were also happy accidents. Take, for example, George de Hevesy. He was a Hungarian chemist famous for many things, including discovering the element hafnium and dissolving two Nobel Prize medals in World War II to hide them from the Nazis. However, it’s a little-known fact that Hevesy’s work on radioactive tracers, which won the 1943 Nobel Prize in Chemistry, originally stemmed from a stunt he performed on his landlady.

Before we get on with this spicy story, let’s think back to year seven Chemistry class. Ernest Rutherford discovered that all atoms have a nucleus of positively charged protons and neutrally charged neutrons. The number of protons in the nucleus defines that atom’s elemental identity and chemical properties. Atoms with the same number of protons, but different numbers of neutrons, are called isotopes. For example, carbon-12 and carbon-14 both have six protons and behave in the same way chemically, but the first isotope has six neutrons while the second has eight. These excess neutrons make carbon-14 unstable and radioactive.

Back to Hevesy – in 1911, he began working under Rutherford (!!!) in Manchester. The Austrian government sent the lab hundreds of kilograms of lead, which contained atoms of the radioactive element ‘radium D’. Rutherford basically dared Hevesy to work out a way to separate the radioactive atoms from the stable ones in this material, and of course Hevesy, young and optimistic, enthusiastically obliged. However, it turned out that the task was impossible since the unknown element radium D was actually just another isotope of lead.

Hevesy, frustrated by his research and sick of bland English food, grew suspicious of his landlady. She claimed to make fresh meals every day for her tenants, but Hevesy was sure that she was recycling his leftovers. In fact, he was so sure that he decided to use the lead from his research to prove it. While the landlady wasn’t looking, he sprinkled a bit of the radioactive powder over his meal. Sure enough, when Hevesy came in the next day with a radiation detector he discovered that his ‘fresh’ stew was incredibly radioactive. Either the landlady’s secret ingredient was uranium, or she was reusing his left-overs.

After confronting his landlady (who was, weirdly, not angry that he had poisoned her food), Hevesy went on to use the same idea to create the first radioactive tracers. Radioactive lead atoms, like the ones in his stew, behave the same way as stable lead atoms, but with the added superpower of emitting radiation. Hevesy first used these superhero lead atoms as radioactive tracers in broad bean plants. These tracers are absorbed by the plant just like any other lead atom, but then decay inside it and release signals, giving a detailed map of exactly where the leadatoms go. This idea revolutionised the field of chemical and biological imaging, providing scientists with accurate methods to study many different systems. This eventually evolved into the field of medical imaging,which helps doctors diagnose and treat millions of patients each year. It’s funny to think that so much of what we know about science today came from a petty revenge scheme.