You can experiment with electricity with just a few supplies, and some simple processes. By building your circuits on file cards, it is pretty easy to try out circuit ideas and see for yourself how they work.
Aluminum HVAC tape
Clear adhesive tape
Electrical components (LED, light bulb, motor, etc)
Soldering iron (optional)
Cut the aluminum tape in half lengthwise
Attach the tape to the cards so there is some overhang to the back of the card.
Clip the battery pack to a card.
Clip a second card to the first.
Tape an LED to the second card.
Orient the LED so that it lights up.
Substitute cards that have motors, light bulbs and other electrical components.
Build a card that has a gap on one of the rails. Use this to see what materials will conduct or insulate.
Conductors will allow the circuit to be completed. Insulators will not complete the circuit.
Make switches with a combination of conductors and insulators.
There are photos of this project.