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People Circuit

In this model, the students are the electrons, and the energy provided by the battery is represented by candies. The current is the amount of charge (electrons) moving in the circuit per unit time, measured in amperes.

A resistance slows the electric current; resistance is represented in this model by having the students climb over a chair. In order to increase the electrical current, we must speed up the movement of electrons; we do this in the model by adding extra energy in the form of extra candies (in a real circuit, you would add more batteries, or use a higher-voltage battery).

Students will feel warmer as they speed up, which mimics what takes place along a wire in a real circuit: as electrons pass through a resistance they release energy as heat

Objectives

  • Students will model a circuit and demonstrate the inverse proportionality of current and resistance

Materials

  • students
    stool, chair or box
    masking tape
    box of small candies (check for allergies and food restrictions)

Key Questions

  • How could we increase the current (in other words, how can we make the electrons move faster)? (Add more energy per electron)

What To Do

Preparation:

Use the masking tape to outline a circle on the classroom floor.

Activity:

  1. Students form a circle (along the masking tape) to represent the wire.
  2. Explain that the students are electrons. There are always electrons in the wire, and they are always moving randomly, a little bit in every direction.
  3. Choose one of the students to be the power source (battery). This student holds a box of candy – the candies represent “energy”. The closest student to the battery moves forward to get a candy. The other students follow immediately, moving along the “wire” in a loop.
  4. As the electrons pass the battery, they get energy (candy).
  5. Next pick someone to be a switch. The switch, when off, will completely stop the electron movement. The switch could either put up their hand, or turn to the side to represent “off”.
  6. Have the circuit practice on and off a couple times. Note that when the switch is off, all the electrons stop at once (they don’t pile up somewhere).
  7. Now put a stool (or a chair or a box) somewhere along the “wire”. This represents a resistance. The electrons have to climb over the stool to move forward. The whole electron chain will slow down, showing that the current slows down when there is a resistance.
  8. How could we convince the electrons to move faster through the resistance? We could hand out more candy – maybe two candies each time they pass the energy source! This represents a greater voltage (more energy per electron). 

When the box of candies is empty, the battery is “dead” and the current will stop. Note that the battery gets used up faster if you pass out more energy per electron

Extensions

Other Resources

Science World Resources | Full Unit | Playful Circuits