Maze-traversing oil drops

Physical chemist Bartosz Grzybowski and colleagues at Northwestern University have created a microfluidic system that solves mazes like a lab rat. The system is very simple–besides the maze itself, there’s the dyed drop of acidic oil that actually traverses the maze, the basic hydroxide solution that fills the maze, and the acidic lump of agarose gel that marks the maze’s exit–but results in an apparently complex behavior. The droplet at right actually took a couple of wrong turns and back-tracked to correct them. [via Neatorama]