The Basics of Circuits

An Electricity Unit Activity

By: Jon Wilson, NMGK-12 Fellow

For: Mrs. Barranco’s 2nd Grade Class

School: Lafayette Elementary

Directions1. Print out these slides and familiarize yourself with the idea of making human circuits.2. Use the slide entitled Simple Electric Circuit Basics to help understand the two different types of simple electric circuits.3. This presentation should come after the “Basics of Electricity” slide show and before the human power grid game is played.4. Break the students into small groups, and have one battery and one light bulb for each small group.5. First, discuss the parts of a simple electric circuit (both series and parallel have the same basic parts) such as a source (battery), two wires, and a load (light bulb or appliance). 6. To each small group give one student the battery and one student the load and call the rest of the students the wires.7. Using the provided slides on series circuits, line each group up into a pattern resembling a series circuit. A basic circle with the battery and load separated by an equal number of wires.8. Once the series circuit has been assembled, tell the students about how a battery uses a chemical reaction to generate electrons that in turn generate electricity. The student holding the battery should have one of his/her arms labeled at the positive or negative side.

9. Have all the students hold hands making a connected circuit. Since the person holding the battery and light bulb will not have both hands free, the students next to them should put his/her hand on that person’s shoulder to complete the connected circuit.10. Since this is a human circuit, a chemical reaction to generate the electrons flowing needs to be made. To mimic this action, you as the teacher should tap the student holding the battery to start the flow of electrons. 11. As soon as you tap the battery, the person on the + side of the battery person should squeeze the person’s hand next to them. This is the electric pulse being transmitted down the wire.12. Tell the students that as soon as their hand is squeezed they should squeeze the person’s hand next to them. The person next to the load then taps the load to let him / her know the pulse is there and the load is then raised in the air. 13. Once the student holding the load raises it in the air, the person next to him squeezes the person’s hand they are connected to, sending the pulse on its way back to the source. 14. As the pulse makes it back to the source, the source then raises the battery in the air completing the circuit and showing that electricity needs a connected loop to work. The same steps should be followed with the parallel circuit. Show what happens when the circuit is broken or the bulb is blown, and tell how one thing can work in a parallel circuit while another does not in a series circuit.

GoalsThe Basics of Circuits

The basics of understanding electricity and how it moves through wires into our homes can all be understood by working with and learning about simple electric circuits. An electric circuit is an unbroken path along which an electric current is able to flow. A simple circuit might consist of an electric cell (the power source), two conducting wires (one end of each wire is attached to each terminal of the cell), and a small lamp (the load) to which the free ends of the wire are connected and operate.

These activities will develop the student’s understanding of simple series and parallel electric circuits. Each circuit type will be illustrated graphically and performed in a hands-on manner by the students in two different ways. Example circuits will be constructed for the students to see each type of simple circuit in action and what happens when certain things are changed. All the students will participate in building a human “series” and human “parallel” circuit.

The fundamental concept demonstrated here is that electricity cannot travel through a path that is broken, it must travel in a continuous loop. This will explain why one circuit may light the bulb and another does not. Finally, the basic elements needed to create a simple circuit are given.

Basic Idea for all CIRCUITS1.

+

_

More Electrons

To light up the light,the electricity needs tomake an UNBROKENcircle from the batteryto the light bulb and backto the battery.

Less Electrons

Electron Flow DirectionThe electrons always move in a direction fromwhere there are more to where there are less of them present. In all batteries, the + means that side of the battery will be producing oremitting electrons to the - side of the battery.The generation of these electrons comes by wayof a chemical reaction.

Source

Load

Wires

Series Circuit2.

+

_

ONEComplete loop or circle with no breaks

Bulbs are all connected in a singleline with the battery.

Source

LoadsWires

Parallel Circuit3.

+

_

THREEComplete loops or circles with no breaks

Loop #1 Loop #2 Loop #3

Bulbs connected to the battery and to eachother are called a “parallel” connection.

SourceLoads

Wires

The Human Series Circuit Setup4.

Source

Loads

Wires

Students

The Human Parallel Circuit Setup5.

Students

Source

Loads

Wires

Inference Questions and Points6.

1. If one Christmas light on a string goes out and all the others still work, what type of circuit is connecting them together?

2. What type of circuit makes it possible for lights on one side of the street to be out while lights on the other side of the street are still on?