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Make a Light Bulb - Results Form
Use this form to record the results of your "Make a light bulb" experiment.


Words you should know

ELECTRICAL CIRCUIT: the path of the current as it flows through a wire from an energy source (like a battery) and back to an energy source, usually from positive to negative.

CURRENT: the flow of electrons in a circuit.

FILAMENT: material that gives off light in a light bulb when heated by an electrical current passing through it.

SHORT CIRCUIT: the interruption of the regular flow of electricity when the circuit is shortened, often by crossing bare wires.  In household current this causes heating up of wires and often a fire.

Problem: How long can you make your iron filament glow? 

Thomas Edison tried hundreds of times to make filaments that would glow and not burn up.  He used many different materials, from cardboard to bamboo.  Edison was persistent--he never gave up trying until his project worked!

What is Happening?

The electric light bulb works because you have made a complete circuit with electrical current flowing out from the battery, through the filament and back to the battery.  The electricity flowing through the wire produces heat and makes the filament glow.



Test number Number of strands of iron wire Number of seconds filament lit Burn or glow

The Lemelson Center for the Study of Invention and Innovation
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