When I was an undergrad I found NMR to be one of the trickiest techniques to get my head around. I think it was because the technique involves so many concepts that run counter to everything we’ve learnt before. After all in school we get told about ferromagnets and thats it. Then at uni suddenly someone is trying to tell us that actually there’s these other things called diamagnets and paramagnets, which means that even water is magnetic!
So now that I get to teach NMR I like to demonstrate diamagnetism right from the get go. Of course diamagnetism is really weak so you need a precision built, low friction setup. So I set about building one with ….
- 2 grapes
- A wooden skewer
- A pin
- An old film canister
- A neodymium magnet. I get mine from emagnets. The stronger the better I use one with 20 Kg pull.
- Don’t let kids play with them.
- Don’t put them near your credit cards, phone, watch or any other electrical equipment.
- Don’t put 2 magnets anywhere near each other because they’ll fly towards one another, shatter and send chunks flying.
- If you have any medical implants don’t go anywhere near them.
- Read the safety instructions that come with the magnets.
1. Push the 2 grapes onto either end of the skewer