The Mechanical Computer That Calculated Nuclear Particles

Before digital supercomputers, Enrico Fermi solved complex physics problems using a wooden cart. The FERMIAC used rolling wheels to simulate the chaotic path of neutrons through materials by hand.

During the Manhattan Project, calculating how neutrons traveled through matter was incredibly difficult for humans to do alone. Fermi built this analog device, essentially a rolling plotter, to mimic random particle collisions. By pushing the machine across a map, he generated data that saved months of tedious manual work. It remains a brilliant example of how simple physical tools can tackle deep scientific mysteries.