My partners and I have been planning to use motors activated by circuits, but we're having a problem with actually connecting the wires to the motors. We're using K'Nex motors, and unscrewing the battery cover part, taking out the batteries, and trying to connect the wires is too hard because of the limited space. After that, we tried connecting the wires to the AA batteries with duct tape so they would stay on, but then they couldn't fit inside of the motor, anymore. Next, we just failed at using hot glue.
What kinds of motors are easy to use and find in stores?