If you have a flashlight handy, you have a working example of a simple battery-and-bulb circuit.
a. Open the flashlight and remove the batteries and bulb. Can you see how the switch operates? What makes contact when the switch is closed? Sketch the switch to make this clear.
b. How are the connections made to the bulb in the flashlight?
c. Leaving the bulb in its socket, can you get it to light by using external wires to make connections to the batteries? Sketch the arrangement that works.