Teachers never retire they just lose their class, well this is the HL class I'm losing this year (I promised to feature the photo in a blog post so here they are). Not that I'm retiring or anything. Nice bit of product placement in the photo too. I hadn't realised that I had accumulated such a collection of sticky stuff, blue tak, duct tape, insulating tape and pressure sensitive sellotape. I wasn't sure what pressure sensitive sellotape was so I did an experiment with it. It seems that the amount of adhesion depends on how hard you press, this makes it possible to align it properly before it sticks. Alternatively it means if you don't press hard then things you stick to the wall will fall off. The pink things are obviously flying pigs except for the pink thing on my table which is a plastic bag.