Researchers have built logic gates–a physical implementation of Boolean logic–using droplets on a superhydrophobic surface. The video above demonstrates their flip-flop memory gate. Incoming droplets travel on a single track, striking a stationary “memory droplet” which then goes into one of the two output tracks according to its memory state. The memory state of the droplet relies on its position; the droplet sits on an infinity-shaped depression. When the incoming droplet strikes the sitting one, the droplet will exit via the track closest to its depression. The droplet that struck it will, as a result of the momentum transfer of the collision, rebound the opposite direction into the other depression, thereby storing the opposite memory state. See here for videos demonstrating other logic gates. (Video credit: H. Mertaniemi et al.; submitted by L. Buss)
Liquid Logic Gates
