It has been one of those ‘are you actually going to do any work’ weeks, when every day promises a different trip or talk or lecture or meeting. After Highgate last week and the STEM talk and the first year projects, I jumped on a train to Manchester for the British Science Association’s Science Communication Conference.
I‘d got the graduate school at Imperial to fund it (£1450, nice) so 7 of us PG students were able to attend. All-in-all, I was left with a bit of a sour taste in my mouth- I felt surrounded by opinionated people who had already decided nothing would change in science, or the media, and we should just back off a bit. There was a great session on funding and some funny characters, but very little in the way of actual content or a coherent take home message. On Saturday (no rest for the wicked) I helped with the Alumni Class of ’65’s reunion in the Blackett Lab. This was crazy moving. The alumni were incredibly happy to see each other and the places that they’d grown up in. The physics department moved into what is now the Blackett Lab in 1959, so when they knew it, it was brand new. Lord Blackett was still ruling the roost, figuring out the earth’s magnetic fields and being pretty mean to the students. He didn’t let them travel in the lifts (our physics department is 12 floors high!), which explains why there were still so mobile! Physics then didn’t make offers based on future A-level results, but gave you a place via telegram a week before term began, and told you to hot-foot it back from Nairobi or Texas. He was also involved with the second world war, designing bombs, against the theoretical physicist Abdul Salam (who was designing a bomb for the ‘other side’). There is way too much to write about, but you could read a book (!). Unsurprisingly, the alumni didn’t want to hang out with us students, no did they really want to see our fancy plasma labs and million-pound workshop- they wanted to sit, where they sat, in lecture theatre 1 and pretend they were 18 again. It was a super moving event, and I am really glad that I could be involved in some tiny way.
Monday was involved a £30 Addison Lee (with a 25 % discount) to a primary school in Enfield, where I spoke about light! It was actually incredibly sweet. The student’s knew a little about light, and a little about Imperial through various older siblings. It’s a very cute school, with a big open playground where teachers come out of their classrooms like parents opening their front doors to their children returning from adventures. At Capel Manor I spoke about the science of light. We worked out the time it takes light to reach us from the sun and looked at how glow-in-the-dark stars work. I did a few little ‘i’m an excited electron’ dances. This week I’ve been involved with I’m a scientist, get me out of here! which has been the most fun thing I’ve ever done in a lab coat. It’s completely reassessed how I teach colour and light, so now I’m going on this kind of tangent…
Colour is all really a ‘trick of the eye’. In or eyes there are millions of receptors, which ‘receive; all of the light coming into the eye. There two types of receptors, called ‘rods’ and ‘cones’. The rods detect blacks and white, and let us see in dark rooms. The cones are responsible for differentiating different colours.
We need to start off by thinking a bit about light. All different kinds of light travel at one speed (299,792,458 metres per second). All the kinds of light form something called the ‘electromagnetic’ (electricity + magnetism) spectrum. We like to make things as easy as possible in physics, so we split the light into different groups according to their energy. This includes things like gamma rays (a type of radiation), radio waves (how we get music in the car!) and microwaves! There’s only one little part of the spectrum called ‘visible light’, and that’s where all the colours of the rainbow sit. There is low energy ‘visible light’ which is red. He is right next to ‘infrared’- the same kind of light that sends signals to your TV to tell it to change channel. At the high energy side there is blue light, then ‘ultraviolet light’, which is the bright bright light from the sun. Just above that are X-Rays, which are so energetic they can break into your body!
When light hits something like a red apple, the little molecules inside the apple start to wiggle around and get excited. Some of the light is absorbed by the apple, and used to heat the apple up. Some of the light is reflected by the apple, and comes into our eyes. Because it isn’t all of the light that went into the apple in the first place, it has a bit of a lower energy. This is why the light appears to be red! But the meaning of the word ‘red’ varies from person to person, because of the different cone receptors in our eyes. The cone receptors all respond differently to different energies of light- some are great at seeing the low energies, some great at the high energy blue light. Some people have more of the red receptors than the blue. Also, we learn about colours just from words- my mum told me the sky was blue, and so the colour I see the sky is what I have learnt is blue. But if she’d actually told me the sky was pink, I would have believed it! We have come up with the names for colours because that is what we all agree on.