Series and Parallel Circuits

"The idea that a break in an electrical circuitcan stop the currernt flow and thus stop the electrical device or devices in the circuit is quite useful most of the time. However, sometimesit's a real problem. Consider, for example the following circuit:"

Even though only one lightbulb is broken, neither will work. The idea is that the electrons flow through the filament in the light bulb. Notice that on the one light bulb, the filament is broken....therefore, the electrons cannot get to the next light bulb. Several years ago, if you had Christmas tree lights and one burnt out, none of them would turn on. You had to replace all the light bulbs because you didn't know which one was burnt out. Now, they have changed the way the lights are made so that when one burns out, the others will still light up. The picture above is a series circuit. A series circuit is when the electrons flow through the filament. The picture below is a parallel circuit.

The electrons cannot flow through the filament in the burnt out light bulb but they can still flow from one side of the battery to the other.