A dowel shaft can be attached to the motor shaft with a piece of tubing slid onto either a red motor shaft bushing or the motor pulley (put on backwards).

If you are holding the motor and attached shaft loosely in your upturned palm, with the solar panel attached and pointing toward the sun, and with the tubing slightly bent, it will vibrate - a primitive sun-drum.

Consider that overall these solar panels are about 12-1/2% efficient, converting only about 1/8 of the total received solar energy into electricity. If the solar panels were 100% efficient, you would need a panel only 1/8 this size to produce the energy you feel in your hand.

That is to say, the energy you feel in your hand is the energy in a postage stamp of sunlight.