by James Kingsland
It's 200 years to the day since the birth of Robert Bunsen, the German chemist famous for inventing the ubiquitous Bunsen burner. But Bunsen's scientific legacy is far, far more important than that – he was one of the most ingenious chemists of the 19th century, whose work led to the discovery of a new element, an antidote for arsenic poisoning and would one day provide clues to the constituents of stars.
For this modest, quiet man, the Bunsen burner was simply a means to an end. Bunsen and his faithful lab assistant Peter Desaga (surely the original Beaker?) needed a very hot, clean flame to pursue their main interest: the characteristic, brightly coloured light emitted by different elements when they are heated. Bunsen was the first person to study these "emission spectra" systematically.
Bunsen and his colleague Gustav Kirchhoff went on to split this light into its constituent wavelengths using a prism, in the process inventing a prototype of today's spectroscopes and founding the brand new scientific field of spectroscopy. They discovered that every element emits a distinctive mix of wavelengths that can be used like a fingerprint to identify its presence.
Bunsen identified the emission spectra of sodium, lithium and potassium. He also detected a previously unseen blue spectral line produced by mineral water which he guessed was being emitted by an unknown element. Having gone to the extraordinary length of distilling 40 tonnes of water to isolate 17 grams of the new element, he called it caesium, meaning "deep blue" in Latin. (As the radioactive isotope caesium-137 – with a half life of around 30 years – it's responsible for the deadly legacy of nuclear accidents like Chernobyl).
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It's 200 years to the day since the birth of Robert Bunsen, the German chemist famous for inventing the ubiquitous Bunsen burner. But Bunsen's scientific legacy is far, far more important than that – he was one of the most ingenious chemists of the 19th century, whose work led to the discovery of a new element, an antidote for arsenic poisoning and would one day provide clues to the constituents of stars.
For this modest, quiet man, the Bunsen burner was simply a means to an end. Bunsen and his faithful lab assistant Peter Desaga (surely the original Beaker?) needed a very hot, clean flame to pursue their main interest: the characteristic, brightly coloured light emitted by different elements when they are heated. Bunsen was the first person to study these "emission spectra" systematically.Bunsen and his colleague Gustav Kirchhoff went on to split this light into its constituent wavelengths using a prism, in the process inventing a prototype of today's spectroscopes and founding the brand new scientific field of spectroscopy. They discovered that every element emits a distinctive mix of wavelengths that can be used like a fingerprint to identify its presence.
Bunsen identified the emission spectra of sodium, lithium and potassium. He also detected a previously unseen blue spectral line produced by mineral water which he guessed was being emitted by an unknown element. Having gone to the extraordinary length of distilling 40 tonnes of water to isolate 17 grams of the new element, he called it caesium, meaning "deep blue" in Latin. (As the radioactive isotope caesium-137 – with a half life of around 30 years – it's responsible for the deadly legacy of nuclear accidents like Chernobyl).
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