A small electric motor wired to flashlight batteries in a classroom project apparently overloaded and blew up Monday, injuring nine elementary school pupils.

The injured, ranging in age from 8 to 11, were treated for cuts.

Principal Jack Penczar said pupils were handling the motor while morning attendance was being taken.

Fire department Capt. Randy Ogden said pupils at the Children’s Academy of Arizona had wired the batteries to an electric motor the size of a tennis ball. Ogden said he believes the motor overloaded when it was turned on.