Sound can be conducted through the bones of your skull. Drew Vanden Heuvel has designed a project in which emerging engineers can construct a bone-conduction contraption. A pair of old earbuds and a tiny electric motor are connected and plugged into a mobile device. If you place the pin of the motor between your teeth, you can hear the sounds or music from the device. Drew explains how an oscillating current in the motor makes the air move and allows us to hear the sounds. This neat project could be part of a unit on sound or on the ear.