Electron Diffraction Tube

Great video. You can make this quantitative for your students by measuring the distance of the first fringe from the centre and divide by the target-screen distance to get an angle. They can then calculate the spacing of the carbon atoms. They'll need some scaffolding; eg they need to work out the speed of the electrons from the accelerating voltage; then calculate the De Broglie wavelength and use the diffraction equation.

I really like this! Our School used to have an EHT Voltage supply unit just like this one!!! And I loved demonstrating cathode rays with the apparatus! Alas! The unit is broken!! It's great to have this video to show to my students now! Another great classroom asset!

Very pleased to hear this worked well for you. If there are other demonstrations that you would find it helpful to have shown as a video then we'd like to know, via resources@nationalstemcentre.org.uk.
Thanks
Jenifer

Thankyou for a wonderful set of concise and clear instructions.
As a non-physics technician I found them easy to follow and I'm proud to say I got it working first time.

Excellent video.thanks..

I used the video with non-specialist teachers. Very useful - especially the sensible safety advice.

Brilliant! Another really cool way of getting the point across! A magnet, why not? It would be interesting to have the same diffraction pattern from a laser beam through a pin hole next to the tube and show the magnet doesn't affect the path of the light! Not sure if you mentioned it in the video (I was reading a tweet in that bit, sorry).

Superb video. Tried to set this up myself for the first time a few weeks back and didn't have much success. No problem when I tried it after watching this. Clear, concise and well explained.

Great stuff - will be a great help to schools who have this kit gathering dust in cupboards. A follow up film on the even more useful fine beam tube would be great to see.

Quite good but I would recommend earthing the positive EHT terminal rather than the negative whenever using electron tubes: this ensures that all parts of the apparatus, apart from the very rear, are safe to touch, which is always possible in black-out conditions and reduces electron repulsion as they approach the "earthed" glass tube.
This also eliminates the need for shrouded plugs (although I still use them if available) but it does require the EHT 6V terminals to be insulated to 5kV, which they usually are.

Dear Stuart
Glad you've found these films useful, thanks for the feedback. I've checked with Alom Shaha, who worked on the films and is presenting this one, and a suitable example product is the Edu-Lab EHT supply (Rapid Electronics are one source of this, rapidonline.com). I'll do some more research and add any other suggestions here.
Best wishes
Jen

Very clear and concise, with good tips on safety.

Where can I buy the EHT with built in voltmeter and separate switches?! Mine don't have either. And the shrouded plug leads, too?