A "homoploar" motor is a motor that works with the need for a commutator. The commutator is used to switch polarity between pairs of poles of a motor. This motor has one pole, The explanation uses the right hand rule where the thumb points in the direction of the current, the fingers are in the direction of the b-field, and the palm is the push or the applied force. Current is defined as the flow of positive charge because physicists positive charges flow from high energy to low. In reality electrons move in a circuit. But physicist look at the electric field as energy sources in a circuit. And the field points form high energy to low energy. this happens to be from the positive pole to the negative pole. ) There isn't any sound because this is meant to be used by other teachers in a lecture environment with their students.