Take some electrons, accelerate them at 200,000 Volts, bend them into a tiny beam with electromagnets, fire them through some crystals, bend them again with some more electromagnets…and we see diffraction.

A slightly easier way is to look at the back of a CD, where the tiny lines on the CD diffract light and separate the different colours. Replace ‘light’ with ‘electrons’, and ‘tiny lines’ with ‘rows of atoms’ and we get an electron diffraction pattern that tells us a lot about nano-sized and even smaller structures, and gives a kind of fingerprint for each material. It’s worth the extra hassle, and some of the patterns can be quite beautiful too!