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The Story of the Bunsen Burner

This was one step in that story in understanding how quickly the Universe is expanding.

I have brought along with me something that people at home will be very, very familiar with I’m sure.  Most people will have seen it in the classroom, everyone should have it seen it in their senior school classroom.  This is a Bunsen burner and everybody’s familiar with it but I don’t think many people are actually aware of why it was invented and quite how important it is.  It’s part of a really cool, really long story and there’s this fabulous phrase that we like to use which is ‘Standing on the shoulders of giants,’ the idea is science is a process that we’re just adding to what’s gone before and this was part of a process which has in fact changed the way that we understand the Universe, which I really like.

This was invented in the 1850s by a man called Peter Desaga, actually he invented it for Robert Bunsen who was a professor in Germany and he and his colleague Gustav Kirchhoff, they were actually using it because they needed a really, really hot flame because they’d worked out that if you heated materials they gave off very, very specific colours, what we call wavelengths of light, and those colours could be used to tell you what was in the chemical you were burning.  So they proved the existence of a number of elements.

Now, they burnt these materials and the light came off them and they focused the light through a prism, and a prism  splits light into lots and lots of little bits.  You can see all the different wavelengths, all the different colours that are coming off of that thing that’s being burnt.  Those colours are particular to the elements being burnt and that’s really, really important because that spectrum that was produced is the same spectrum we still use today to try to identify materials.  There’s a technique called radio spectrometry and that is where we point instruments at the stars and look at the wavelengths of light that come off them and it’s the same wavelengths, we’ve extended them a bit into other sorts of radiation but it’s the same wavelengths we’re using to look at the materials that make up objects across the cosmos.

Even more excitingly, these wavelengths change depending on how quickly things in the Universe are moving apart.  And so we can use something called the Doppler Effect,  something called Redshift to understand how quickly objects are moving apart.  And this was one step in that story in understanding how quickly the Universe is expanding.