Science
Strand IV
Use Scientific Knowledge from the Physical Sciences in Real-World Contexts

 

Science/Strand IV
Content Standard 1
All students will measure and describe the things around us; explain what the world around us is made of; identify and describe forms of energy; and explain how electricity and magnetism interact with matter (Matter and Energy)

 

Science/Strand IV/Content Standard 1
High School

 

Science/Strand IV/Content Standard 1/High School
Benchmark 5
Describe how electric currents can be produced by interacting wires and magnets, and explain applications of this principle.

Benchmark Clarification

Electric currents can be produced by interacting wires and magnets. This principle is applied to electric generators where the direction of the current flow in a wire changes as a magnetic field reverses.

This type of current is called alternating current (AC) because the current changes direction. Another type of current is direct current (DC), where the current flows in one direction only.

Students will:

  • Explain how a wire moving through a magnetic field creates an electric current in the wire

See (SCI.IV.3.MS.4).

Key Concept / Real World Context / Instructional Example / Assessment Example / Resources

 

Science/Strand IV/Content Standard 1/High School/Benchmark 5
Key Concept

  • current flow and direction
  • magnetic fields

 

Science/Strand IV/Content Standard 1/High School/Benchmark 5
Real World Context

  • generators
  • alternating current
  • direct current

 

Science/Strand IV/Content Standard 1/High School/Benchmark 5
Instructional Example

Benchmark Question: How do electricity and magnetism interact with matter?

Focus Question: How can electric currents be produced by interacting wires and magnets?

Following a class discussion about how an electrical current is produced, the teacher will perform the following demonstration and introduce the concept of a magnetic field producing an electric current:

Procedure:

1. Wrap 0.5 m of wire around a compass (top to bottom).

2. Attach the loose ends of the wire to a dry cell (battery) and observe the needle in the compass.

3. Discuss that the needle moves because electricity is moving through the wire and creates a magnetic field that interacts with the needle.

4. Make a coil of wire by wrapping approximately two m of wire several times around a plastic bottle with the top and bottom removed.

5. Remove the dry cell from the ends of the wire around the compass, then twist these ends together with each of the exposed ends of the two m of wire coil around the bottle.

See Compass Galvanometer Diagram below:

 

6. Place this setup on an overhead projector to project onto a screen.

7. Take a bar magnet and quickly pass it back and forth through the center of the bottle with the coil; observe the compass needle.

8. Have students pair up, discuss, and then create a written description of what they think is happening.

9. Have students share their ideas with the class and debate which pairs have the most accurate ideas.

Constructing: (SCI.I.1.HS.5).

Reflecting: (SCI.II.1.HS.1).

 

Science/Strand IV/Content Standard 1/High School/Benchmark 5
Assessment Example

Students will label the Compass Galvanometer Assessment Diagram below and list the sequence of events in the process shown. Students may include the following steps:

1. Magnetic field from bar magnet causes current to flow in wire.

2. Current flow produces a magnetic field.

3. Generated magnetic field moves the compass needle.

(Give students rubric before activity.)

Scoring Rubric

Criteria

Apprentice

Basic

Meets

Exceeds

Accuracy of labels

Labels correctly one part.

Labels correctly two parts.

Labels correctly three parts.

Labels correctly four or more parts.

Correctness of explanation of process

Describes one step correctly.

Describes two steps correctly.

Describes three steps correctly.

Describes three steps correctly and relates to alternating current and/or movement of electrons.

 

Science/Strand IV/Content Standard 1/High School/Benchmark 5
Resources

Webliography.
http://mtn.merit.edu/mcf/SCI.IV.1.HS.5.html

Fundamentals of electricity.
http://www.electronicstheory.com/html/e101-1.htm

Michigan Operation Physics.

Simple electric motor.
http://members.tripod.com/simplemotor/