Simple Stepper motor for my experiment?
I would recommend tweaking your choice of independent variable slightly. I would consider each coil to be either ON, OFF, or ON(Reversed). I would then consider which coils are energized to be the independent variable.

I think this is a great experiment. You should be able to build a working model similar to the diagram you posted. You can use toggle switches to control the coils and "step" the motor.

A DPDT toggle switch can be hooked up so that middle is off, up is current in one direction, and down is current in the opposite direction.
See here.