IBM scientists have measured the force needed to nudge one atom: one-130-millionth of an ounce of force pushes a cobalt atom across a smooth, flat piece of platinum, and one-1,600-millionth of an ounce of force pushes it across copper.

To measure the force, an atomic force microscope tip was attached to a small tuning fork. Changes in the frequency of the tuning fork’s vibrations as it pushed the cobalt atom let the scientists calculate the force applied.