Method

1) You need to make a complete series and parallel electric circuits.

*Series* 1. You need to take a series battery holder and put the batteries in
2. Put a piece of metal at each end
3. Connect electric wires on the metals
4. Connect lightbulb at the other end of the wire

*Parallel* 1. You need to take a parallel battery holder and put the batteries in
2. Put a piece of metal at each end
3. Connect a electric wire at each end of the piece of metal
4. At the end of the electric wires from step 3, connect another electric wires.
5. At the end of the electric wires from step 4, connect a light bulb.

2) Compare the brightness of the light bulbs. Back to home