Credit where credit's due
Science metaphors are remembered more than their creators
30 March 2008
Analogies and metaphors can lead to misconceptions, but ultimately they are an invaluable tool, not just in teaching science, but also in doing it
When you think of an atom, do you picture a mini-solar system, even though you know this is wrong? Did you go to a school where the Biology teacher made you draw pictures of policemen, security guards or even an army to represent the immune system? Or perhaps, like me, you had a Chemistry teacher who told you that positive ions bond to negative ions like lovers in an ardent embrace who, if separated, would rush back together with astonishing speed.
If you’ve had any kind of science education, chances are you’ve got a bunch of such analogies and metaphors stuck in your head, and you use these to think of the natural world, even though you might know that things are not really like that. Just last week, when asked why the resistance of a wire increased when it got hot, I had to resort to talking about atoms as little balls which “wiggled around more” as the wire got hot and therefore got “more in the way of” other little balls called electrons which were trying to move through the wire. I’m sure that this description would mortify some physicists, but it was one which provided a useful picture to my audience and helped them understand what was going on in that particular natural phenomenon. Of course, analogies and metaphors can lead to misconceptions, but ultimately they are an invaluable tool, not just in teaching science, but also in doing it.
A common way of showing people how the universe can expand in all directions without having a centre of expansion is to draw dots on a balloon and blow it up. If you look at any individual dot, you can see the other dots move away from it as the balloon expands. It is a useful demonstration and I have used it more than once in my own teaching. However, it was only recently that I read that it was Arthur Eddington who first developed this metaphor, back in 1931.
Some analogies may be so obvious that there is no single “author”. However, I suspect that this is less often the case than might be imagined. Unlike the celebrated geniuses who have Laws of science named after them, we are frequently ignorant of the people behind the metaphors and analogies with which we are most familiar and which we find of such great use.
I started thinking about the unfairness of this recently, while making a TV series about the history of particle physics. One of the items in the series was about the hunt for the Higgs Boson – a particle which has never been “seen” but which is predicted to exist by the Standard Model of Physics. The script required us to explain what the Higgs Boson is. If you watch the programme, you’ll hear the presenter, Dr Brian Cox, say: “The Higgs mechanism is quite a complicated bit of physics, but we’ve had over forty years to come up with good analogies, and here’s one of the best”. He then goes on to present what is probably the most widely used analogy for the Higgs, but neglects to mention that it was thought up by Professor David Miller of University College London.
I have to take some of the blame for this, as I wrote most of the script for the programme. Despite trying, we just couldn’t make the sequence work if we had Brian say that it was David’s analogy – it made the script just that few seconds too long and complicated, something that was unacceptable in a programme that was already regarded as being difficult and complex by TV standards. I felt bad about this, as I thought David really deserved to be acknowledged. But in the end I had to accept that the script worked better without any mention of him.
Fortunately, a few months later, I was given the opportunity to make amends. I was approached by another particle physicist, Dr Tara Shears of the University of Liverpool, to make a series of films about the science behind the Large Hadron Collider (LHC) at CERN. One of the films she wanted us to make was about the Higgs Particle, which the LHC may finally reveal. So, we recreated the scene I filmed with Brian, albeit on a much lower budget. This time, however, we not only credited David as the author of the analogy, but also included the story of how he came up with it. I won’t recount the tale here, as I hope you'll watch the film below (which is only two minutes and nineteen seconds), but I will tell you that the version that appears in both films, and that has appeared in countless lectures about the Higgs Particle, is not really the one David first came up with. In his original version, the analogy involved “an attractive young lady” and a room full of journalists.
I have heard David Miller’s explanation for the Higgs Mechanism, or variations on it, in a number of public lectures. It also appears on numerous websites. Neither lecturers nor websites like these concern themselves with the provenance of the analogy. But Brian Cox was right – it really is the best analogy we have for what is otherwise a complicated idea. I hope this article goes a little way towards making up for the lack of credit David seems to have received for his brilliant contribution to science communication.