Friday, 28 March 2014

Liquid drop analogy

Here's the rain running down the window of the bird hide on Lamb Island at Threave. It was a good place to be during the shower - but at least the sun came out later. It reminded me of the Liquid Drop Analogy in Physics. I teach that if you get an electron to join a proton, you get a neutron. This is called electron capture. So in some way, a neutron could be thought of as a proton and an electron stuck together. It makes sense because a neutron is a tiny bit heavier than a proton and also that beta-minus decay is like the glue coming unstuck as a neutron changes into a proton by spitting out an electron. However, if you look inside a neutron, you won't find a proton and an electron. It's like 2 raindrops running into each other. Sure, you get a bigger drop but if you take the bigger drop apart, you won't find two distinct small drops. The analogy is that the neutron is like the big drop made when the two smaller ones join up. Oh, and the Blue-winged Teal wasn't there!