Images: Hot wheels for molecules

Working on a molecular scale, Rice University has created three- and six-wheeled nanocars, including a "Mini Cooper" that measures two atoms by two atoms and a nanotruck that can carry other molecules. When an electrical field is created and gold foil is heated to 200 degrees Celsius, the nanocar rolls forward, as in this artist's rendering.

The wheels on the nanocar are buckyballs, spherical molecules made from 60 carbon atoms. Although bonded to the axle, they spin, allowing the car to move forward.