Today is Global Concerns day which means a series of lectures and workshops on a topic of global importance. Todays theme is rainforests. Because this is an environmental topic students handed out green balloons which were bounced about in the auditorium. Reminded me of Brownian motion but green, would be interesting to analyse the "random" walk. Not really random of course since students will try to keep the balloon in play. Might work better if they were blindfolded, no, forget that idea. I once worked at a school where the head of physics was Mr Green and the head of chemistry Mr Brown. All very confusing for a colour blinder.