E1 practical: Helium spectrum support
Thhe good thing about this method is that all the students use the same light source so you only need one. You can use standard diffraction gratings if you have enough but I used pairs of spectrum glasses that I bought from Ebay which are not only cheap but add a bit of fun to the practical. These don't come with the grating spacing stamped on them so the students won't be able to compare their result with a...