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Upstairs, Downstairs: Turning on a Light from Two Places *

Time Required Short (2-5 days)
*Note: This is an abbreviated Project Idea, without notes to start your background research, a specific list of materials, or a procedure for how to do the experiment. You can identify abbreviated Project Ideas by the asterisk at the end of the title. If you want a Project Idea with full instructions, please pick one without an asterisk.


Maybe somewhere in your home there's a long hallway or a stairway with a light that you can turn on from either end. It's a nice convenience, but did you ever wonder how it's wired up to work that way? The goal of this project is to build a similar circuit with switches, flashlight batteries and a flashlight bulb (obviously, household circuits are not safe to experiment with). You'll need to understand the difference between connections made in series and connections made in parallel in an electric circuit. For materials, you'll need 2 SPDT (single-pole, double throw) switches, a flashlight bulb, a bulb holder, 3 or 4 D-cell batteries and some insulated connecting wires with alligator clips. You can connect multiple D-cells together by laying them sideways and taping them end-to-end (with the + pole of one battery touching the βˆ’ pole of the next, just like in a flashlight). Tape paper clips to the + pole of the top battery and the βˆ’ pole of the bottom battery so you can connect them to your circuit. (Rosner, 2000)

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Science Buddies Staff. "Upstairs, Downstairs: Turning on a Light from Two Places" Science Buddies. Science Buddies, 30 June 2014. Web. 24 Oct. 2014 <http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_p045.shtml>

APA Style

Science Buddies Staff. (2014, June 30). Upstairs, Downstairs: Turning on a Light from Two Places. Retrieved October 24, 2014 from http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_p045.shtml

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Last edit date: 2014-06-30


Rosner, M.A., 2000. Scientific American Great Science Fair Projects. New York, NY: John Wiley and Sons.

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I did this project I Did This Project! Please log in and let us know how things went.

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