"It is easy to measure electric current. But it is extremely hard to watch the individual electrons which make up this current. Electrons race through the metal with a speed of several million meters per second, and the distance they have to cover between two adjacent atoms is very small. This means that tiny time intervals have to be resolved in order to watch the electrons dashing through the metal.
Measurements in Garching (Germany) and theoretical calculations at the Vienna University of Technology (Austria) have now made this possible. As it turns out, the motion of the electrons in the metal is remarkably similar to ballistic motion in free space. The results have now been published in the journal Nature..."