Who knew what a few hundred bacteria could do with a little cooperation? Andrey Sokolov of Princeton University, Igor Aronson from the Argonne National Laboratory and Bartosz Grzybowski and Mario Apodaca from Northwestern University found out after placing microgears (380 microns long with
slanted spokes) in a solution with the common aerobic bacteria Bacillus subtilis. The scientists observed that the bacteria appeared to swim randomly but occasionally collided with the
spokes of the gears and turned them.