Home Chapter 3: Toys for Understanding

Chapter Challenge
Homes For Everyone (HFE) identified a need to educate children about electricity and how it is generated. HFE wants to approach this with toys. Students are challenged to prepare a kit, with materials and instructions, that children use to build a toy with a motor and/or generator. This toy will serve as a tool to illustrate how the electric motors in home appliances work or how electricity can be produced from an energy source such as wind, moving water, or some external force.

Chapter Summary
To gain understanding of the science concepts of energy conversions necessary to meet this challenge, students are engaged in activities to learn about electricity and magnetism. These experiences engage students in the content from the National Science Education Standards.

Activity Summaries

Physics Principles

Activity One: The E & M Connection

Students investigate the relationship between electricity and magnetism by testing the effect of a magnetic field on current-bearing wire and on a compass.

• Electricity
• Magnetism
• Magnetic fields

Activity Two: Electromagnets

Using the hand generator to construct an electromagnet is the first step in this continued investigation of the relationship between electricity and magnetism. Students test the strength and find polarity of electromagnets made with different core materials.

• Electromagnets
• Solenoids

Activity Three: Detect and Induce Currents

Students construct a Galvanometer as they learn that a compass can detect the presence of a magnetic field. They use the Galvanometer to create a current similar to the process used by Faraday and Henry, manually alternating the motion of a magnet.

• Galvanometers
• Induced currents

Activity Four: AC & DC Currents

The use of human energy to produce electricity is replaced in this activity by a rotating coil motor. While using this motor, students test and describe the voltage in this induced current. They learn the difference between how AC and DC currents are generated. Students also learn to sketch output wave forms.

• Energy conversion
• AC and DC currents
• Electrical waves

Activity Five: Building an Electric Motor

Students construct, operate, and explain the workings of a DC motor. This enables them to measure and express the efficiency of energy transfers. They also read to learn more about the discoveries that led to the generators and motors we use today to obtain useable power and electricity.

• Electricity
• Magnetism
• Energy transfer

Activity Six: Building a Motor/Generator Toy

In this final activity, students apply what they have learned about the workings of an electromagnetic motor and how both AC and DC currents are generated. They must use given materials to design, construct, and demonstrate the physics of a motor or generator.

• Energy conversion
• Electricity
• Magnetism
• AC and DC currents