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## Conceptual Physics:Electromagnetism and Electromagnets Units

An electromagnet works on the principle that an electric current not only allows electrons to flow in a circuit, but also generates a small magnetic field. When a wire carrying electricity is coiled, the magnetic field becomes even stronger. Iron or steel objects surrounded by this coiled electric wire also become magnetized. This combination of electronic energy, coiled wiring and conductive metal object forms the basis of an electromagnet.

### Teaching About Electromagnetism (3)

#### Activities:

This collection of 41 interactive java tutorials would be an excellent choice to connect physics to "real-world" applications.  Designed by well-respected authors, the topics range from simulated magnetic fields and field lines to primers on capacitance, resistance, Ohm's Law, and electromagnetic induction.  Included are simulations on how things work, such as vacuum tube diodes, cathode rays,  capacitors, AC/DC generators, hard drives, pulsed magnets, and speakers.

#### References and Collections:

The TEAL (Technology Enabled Active Learning) project at MIT merges lecture, cooperative learning, and computer simulations of electromagnetic phenomena.  Designed for teachers of introductory physics, it is the pedagogy currently followed at MIT for freshmen physics students.  Comprehensive course notes accompany the simulations.

#### Student Tutorials:

This well-written tutorial from Florida State University helps beginning students navigate the waters of electromagnetic radiation.  The diagram of the electromagnetic spectrum is well-designed, and be sure to check out the simulated 3-D electromagnetic wave.

### Electromagnetic Induction (2)

#### Student Tutorials:

Inductance is a property of an electric circuit in which a changing magnetic field creates an electromotive force in that circuit or in a nearby circuit.  This interactive tutorial for beginning physics students offers comprehensive explanations of magnetic inductance, including sections on Faraday's experiments and Lenz's Law.  Five java simulations illustrate Faraday's Law, self-inductance effects, and patterns of magnetic field lines.

This tutorial gives beginning students a grounding in the physics underlying generators and motors.  Clear and concise illustrations help students differentiate the components of each device.  The author devotes careful attention to conductor coils and how they are used to cut through lines of force and strengthen a magnetic field.   Simple graphs depict the cycles of both AC and DC current waves.

### Electromagnetic Fields (2)

#### Lesson Plans:

How do solar panels work to gather energy from the sun and transform it to electrical energy? In this inquiry-based lab, students work in teams to disassemble a calculator, evaluate the design and operation of its component parts, and improve functionality through redesign. The lesson specifically focuses on photovoltaic technology to get kids excited about semiconductor physics. Includes problem set.

Item Type: Lab Activity
Level: Grades 9-12
Duration: Two Class Periods

#### Activities:

Students gain understanding of electromagnetic radiation as they broadcast radio waves from a transmitter to receiver.  They can manually control the transmitter electron or set automatic oscillation.  The field can be displayed as a curve or vectors, with students controlling the frequency and amplitude.

### Electromagnetic Radiation and the Spectrum (7)

#### Lesson Plans:

Experiential Learning Unit                                                                  Grades 11-12
Absorption of electromagnetic radiation can be much more easily comprehended when students can see a practical application.  This high-quality, standards-based classroom project explores the interaction of UV light with particles found in sunscreen.  The student task is to learn about scattering and absorption of light, then design an ad campaign for a better sunscreen that contains zinc oxide nanoparticles. **NOTE: May be taught as a short mini-unit or as a two week project.

Kids test the limitations of infrared technology using a TV remote control. After gathering data, they devise a plan for adapting infrared to work around a corner or between rooms. Great way to integrate engineering practice into the physical science classroom. Resource includes teacher and student guides, background information, illustrated procedures, and worksheets.

Item Type: Lab Experiment
Level: Grades 6-10
Duration: 2-3 Class Periods

This standards-based experiment promotes deeper understanding of the sun's role in powering our planet. Students build a simple device to measure the amount of solar radiation the Earth receives from the sun. Using data from the experiment, they will then calculate the solar constant -- the amount of incoming solar radiation the earth receives from the sun per square meter per second. Lesson meets numerous national standards for both math and science.

Item Type: Experiment
Level: Grades 9-12
Duration: Two Class Periods

#### Activities:

This three-minute NASA video introduces the seven categories of the electromagnetic spectrum in a way that is understandable for middle and high school students.  Requires Quicktime plug-in to operate.

#### References and Collections:

This multi-chapter tutorial is sponsored by the highly-respected Federation of American Scientists.  For teachers doing a unit on digital imaging, this resource offers a comprehensive look at both theory and applications.

For students having difficulty understanding the classification system of the electromagnetic spectrum, try this tutorial.  It also gives an overview of the technologies emerging in Remote Sensing, which apply the principles of electromagnetic radiation.

#### Student Tutorials:

This well-written tutorial from Florida State University helps beginning students navigate the waters of electromagnetic radiation.  The diagram of the electromagnetic spectrum is well-designed, and be sure to check out the simulated 3-D electromagnetic wave.