Soldering in Space

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.

[Thanks, Rachel!]