Circuits...Parallel and Series Made Simple
Using a few battery holders, batteries, some wire, some bulb holders and some bulbs, you can carry out many electricity experiments. 
If you hook up two bulbs to one battery holder in one circle...
the lights glow very dimly. This is called a series circuit.
Hook two bulbs together with two wires to form a circle. Connect one end of one battery to the left side of one bulb and connect the other end of the battery to the right side of the battery. Each of the bulbs will glow as brightly as one alone would,
but they use up the battery twice as fast. This is called a parallel circuit.
If you have two batteries in series connected to one bulb, you will blow the bulb out, which is why I don't have a picture of that, but if you add two bulbs to the two batteries in series, the two bulbs will light brightly without blowing out.
If you hook up two bulbs to one battery holder in one circle...
the lights glow very dimly. This is called a series circuit.
Hook two bulbs together with two wires to form a circle. Connect one end of one battery to the left side of one bulb and connect the other end of the battery to the right side of the battery. Each of the bulbs will glow as brightly as one alone would,
but they use up the battery twice as fast. This is called a parallel circuit. If you have two batteries in series connected to one bulb, you will blow the bulb out, which is why I don't have a picture of that, but if you add two bulbs to the two batteries in series, the two bulbs will light brightly without blowing out.
Resources:
GEMS: Electric Circuits: Inventive Physical Science Activities
Grade Level: 3-6
Sessions: 11 Sessions
Written by John Erickson and Kevin Beals with Florence Stone
This guide provides a safe, active, and engaging introduction to electricity and electric circuits. The activities spark creativity as students invent their own electrical gadgets, using inexpensive and readily available materials, such as plastic film canisters and holiday lights. The unit opens as students investigate an array of clever electrical devices, first exploring their functions, then learning how their circuits work. The contributions of famous inventors, as well as child inventors, are highlighted. Students keep an “Inventor’s Journal,” recording the development of their electrical knowledge, schematic diagrams, and design ideas. Electrical safety is emphasized throughout the unit. Students explore simple and series circuits; learn about short circuits, and investigate the role of batteries, resistance, conductors and insulators. They invent their own switch design and learn how to draw schematic diagrams. In Part II, for older or more advanced students, they build and compare series and parallel circuits, and pair up to create their own electrical inventions. The unit culminates in an Electric Inventions Festival.
