Worries that quantum effects at small scales lead to a breakdown of Ohm’s law and higher electrical resistance in small wires appear to be unfounded. Hoon Ryu of Purdue University in Indiana and colleagues made wires just four atoms wide and one atom high by embedding phosphorus atoms in a silicon crystal. Contrary to expectations, the resistivity of the material turned out to be very low – about 0.4 mΩ-cm – with a current-carrying ability similar to copper. Moreover, it still obeyed Ohm’s law even at this tiny scale. This is good news for Moore’s law, which could go all of the way down to device sizes of a few atoms across, and it could represent the limit for classical scaling down of electronics.