In the little coffee room on my floor at work, a fridge-freezer has just appeared. It's a standard domestic model, only distinguished by the sign on the door.
"Experiment in progress. Do not open."
I am aflame with curiosity. What's the experiment? Why is it taking place in a fridge? What dreadful calamity would befall me if I took a peek? Is it all a Cunning Plan to stop people stealing this guy's milk? I guess this is why scientists can get into so much trouble. One minute you're thinking, "I wonder what would happen if I dropped a lit match on this large heap of grey powder?", and the next moment all that's left is a pair of smoking boots.