In July 2004, Astronaut Mike Fincke melted some solder aboard the International Space Station. The behavior of the solder’s rosin in zero gravity is fascinating to watch.
The solder, heated, became a molten blob with a droplet of rosin clinging tight to the outside. Solder melts: that’s not too surprising. It’s the behavior of the rosin that amazed. As the temperature increased, the droplet began to spin, round and round, faster and faster, like a miniature carnival ride.