From Looking Glass Universe.

The 4 week live course will run from Jan 6 – 31st. More info here 🙂 https://looking-glass-universe.teachable.com/p/quantum-mechanics-fundamentals1

The rest of this quantum mechanics course playlist is here: https://www.youtube.com/playlist?list=PLg-OiIIbfPj1t7zYsf6aj7wrGb9fghFDk

If you’re interested in doing this experiment, here’s what you’ll need:

-A laser pointer (go for a weak one in a cat toy or clicker, these are the safest)
-Optical grade calcite. I had to scour Etsy to get this one, and it wasn’t even that good. The trouble is that most of them have significant defects that make them unclear. Only buy one you’ve seen photos of on Etsy. If you just let them send you any calcite then it’s unlikely to be a particularly clear piece. It’s better to choose one yourself.
-Polarizing film/ filter. You can get these on Amazon for very cheap!