What is a Resistor?

 

Per Group

  • battery- 6 volt

  • two wires, 12" long with stripped wire ends

  • steel wool or a copper scrubber

  • scotch tape

  • scissors

  • balloon (get the cheap kind; nice latex balloons don't work well with this demonstration)

  • Resistors Worksheet

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    Place the RISE girls into cooperative groups of two or three. Have the girls work together to share the responsibilities of recording data and manipulating materials.

    1. Have the girls in each group inflate and tie one balloon.

    2. Next they need to pull one small strand about two inches long out of either the steel wool or the copper scrubber. Have them cut off the strand. This strand is their electrical resistor. A resistor allows electricity to flow through it but with some resistance which thereby limits the electrical flow to varying degrees depending on the type of the resisitor.

    Next tape the thin strand of wire to the balloon leaving the ends of the thin strand free.

    3. Now have the girls attach the two 12 inch wires to the terminals of the battery.

    4. With wires attached to the battery, touch each end of the thin strand of wire on the balloon with the battery wires.

    5. Wait and observe what happens. (It may take a minute or two before the resistor (thin strand of wire) heats up, popping the balloon. Also, if a high quality latex balloon is use, it won't pop because it is too thick. Also, if the battery is old or weak, it also will affect the "pop-ability" of the resistor.)

    6. Have the girls define what a resistor is and then have them discuss real world uses for resistors. You might want to give them this hint: A fuse is a resistor.

    As an additional activity they could complete the Resistors Worksheet.

    Answers to worksheet: (1.) 4, (2.) 2, (3.) 1, (4.)5, (5.)3

     


    Materials that allow electricity to flow through them are called conductors. Some conductors resist the flow of electrons and slow them down. Others allow for electrons to pass easily.

    An Ohm(R) is the unit for measuring electrical resistance.

    Resistors allow electrons to flow through the conductor, but with some resistance which causes the conductor to heat up or produce light.

    Resistors, such as iron or tungsten wire, allow the electrons to pass but cause some resistance which produces heat (toasters) and/or light (light bulbs).



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    For further information contact Catherine Raymond, Deputy Director of Education.