Hands-on Activity: The Path of Electrons
Educational Standards :
Learning Objectives (Return to Contents)
After this activity, students should be able to:
Materials List (Return to Contents)
What Is a Circuit? Worksheet, one per student
For the entire class to share:
For a class demonstration of how a circuit works:
Introduction/Motivation (Return to Contents)
Who has heard of a circuit? A circuit is a complete path of electrical energy.
Class demonstration: Create an example of a simple circuit using one battery, wire and a small light bulb (see Figure 1).
Electrical energy is all about charge. Who knows what charge is? Charge is the positive or negative force of an atom or how much electrical energy is in an atom. This gets us back to three main vocabulary words when talking about electrical energy and charge: voltage, current and resistance. Voltage is the amount of energy that can be produced by a charge, current is the flow of charge ( electrons), and resistance is anything that keeps the current from flowing. Today, we are going to talk about simple circuits and how engineers get electrical energy to flow in a current.
Remember that a circuit is the complete path of electrical energy. In the circuit we have created here with the light bulb, wire and battery, the battery provides the voltage and the light bulb gives us resistance, by slowing down the flow of charge and changing it into light. The current flows through the battery, the light bulb and the wires.
What might happen if we disconnect the battery? The light goes off because the current has nowhere to flow. This creates what we call an open circuit. It is like an open circle because there is a break in the line of flow. A closed circuit is like a closed circle or a completed circle. Current can only travel through a closed circuit.
What do you think happens if we add more voltage or another battery?
Class demonstration (continued): Make a circuit using two D-size batteries in series and a small light bulb in a light bulb holder.
Why is the light bulb brighter when two batteries are used instead of one? When we put two batteries together, the power going to the light bulb increases. So, the light bulb gets brighter. Power is how much voltage and current together are getting through the circuit to the light bulb.
Engineers must understand circuits when creating any device that uses electrical energy. Products such as radios, televisions and appliances use complicated circuits to make sure everything works at once. For example, numerous circuits are required for a CD player: to make the CD spin, to play the music and to light up the information screen. And that's just a few of the circuits inside a CD player. Do you think you are beginning to understand what a circuit is and why they are important to engineers? Well, let's stand up and see what you know!
Vocabulary/Definitions (Return to Contents)
Procedure (Return to Contents)
Before the Activity
With the Students
Attachments (Return to Contents)
Troubleshooting Tips (Return to Contents)
To conduct this activity without paper and markers, or candy, have the student hold hands in a circle and ask them to represent the flow of electrons by a gentle "squeeze" of hands that flows from one student to the other, around and around the circle. The circuit breaks when the flow of electrons is not smooth, or when two students next to each other do not hold their hands together.
Assessment (Return to Contents)
Vocabulary Review: Have students review the following vocabulary words: voltage (The amount of electrical energy that is able to flow), current (The flow of electrical energy, the movement of electrons), and resistance (Something that keeps the electrical energy from flowing.)
Activity Embedded Assessment
Formation: As a way to actively engage all students and assess their knowledge, re-assign the roles of the switch, battery and light bulb several times during this activity.
Worksheet / Pairs Check: Have students work individually or in pairs on the What Is a Circuit? Worksheet. After students finish the worksheet, have them compare answers with a peer or another pair, giving all students time to finish the worksheet.
Class Discussion: Discuss with the students what happened in the activity. Have them come up with ideas in which the same types of closed / open circuit, energy / electricity flow situations are occurring, for example, a light switch or a remote control.
Name Game: Have the students name the following parts of their circuit by asking the students: Which part of our circuit was ________?
Activity Extensions (Return to Contents)
Have the students use their imagination in drawing and painting the electrons that they use in the "human circuit."
Have students waiting to join the circuit as "insulators," which break the circuit, causing the light bulb to "turn off," even if the switch is "turned on."
Activity Scaling (Return to Contents)
References (Return to Contents)
Dictionary.com. Lexico Publishing Group, LLC. Accessed September 28, 2005. (Source of some vocabulary definitions, with some adaptation) http://www.dictionary.com
ContributorsSharon D. Perez-Suarez, Jeff Lyng, Malinda Schaefer Zarske, Denise Carlson
Copyright© 2005 by Regents of the University of Colorado.
Supporting Program (Return to Contents)Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Acknowledgements (Return to Contents)
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.