A generator is a motor run the other way. The Energy Transformation is Motion>Magnetism>Electricity >Light
This design has a number of useful classroom features. The main form transparent. Its ambidextrous. It has a gear assembly. The motor itself is not transparent but that ground has been prepared with a Simple Electric Motor.
The dexterity challenge for the primary child is that a device like this can be difficult to crank quickly enough to light the regular incandescent flash light bulb that fits in the main front opening. The solution is to attach an LED light assembly, meaning there is a resistor integrated into one of the wires so the LED doesn't burn out. Radio Shack, about $5. Just adding the LED provides the child an opportunity for assembly, aligning the wires and tightening the plastic nuts. There is a color coded, polarity indicating control of error. The LED will flash with very little movement which will satisfy the child even on a first attempt and then provide a a second goal which is to turn fast enough to light both the LED and the incandescent bulb. Because the movement input is her effort this type of generator places the child in the circuit.