If you've been following this blog you might think that I've discovered another way to keep my students amused while they go to the bathroom but actually I haven't. Since I got a SMARTboard about 6 years ago I very rarely do real demonstrations preferring to use simulations showing what I am trying to explain as opposed to spending my time explaining what I am trying to show. Like most science labs my lab used to have a long front bench for the purpose of demos, that went when the SMARTboard arrived. Occasionally I do like to do a real demo, just to keep in touch with reality. The other day I thought I'd give my students a treat and got out the electron diffraction tube. Guess what, it didn't work. I was using the wrong power supply. After class I found the Teltron instruction manual (on the net) and got it to work. I really didn't like the 5000V live lead poking out of the side. Why did they make it so that the plug connects pointing out like that?