Lesson 6: Magnets
Overview:
In this section, you will learn about magnetic material and how some of these material deep inside Earth produce Earth's magnetic field. You will also learn how a magnetic field surrounds all magnets and how moving electric charges produce a magnetic field.
Curriculum Expectations:
Overall Expectations:
D2. Investigate, in qualitative and quantitative terms, gravitational, electric, and magnetic fields, and solve related problems.
Specific Expectations:
D2.1 Use appropriate terminology related to fields, including, but not limited to: forces, potential energies, potential, and exchange particles.
D2.5 Conduct a laboratory inquiry or computer simulation to examine the behaviour of a particle in a field (e.g., test Coulomb’s law; replicate Millikan’s experiment or Rutherford’s scattering experiment; use a bubble or cloud chamber).
D3.3 Use field diagrams to explain differences in the sources and directions of fields, including, but not limited to, differences between near- Earth and distant fields, parallel plates and point charges, straight line conductors and solenoids.
D2. Investigate, in qualitative and quantitative terms, gravitational, electric, and magnetic fields, and solve related problems.
Specific Expectations:
D2.1 Use appropriate terminology related to fields, including, but not limited to: forces, potential energies, potential, and exchange particles.
D2.5 Conduct a laboratory inquiry or computer simulation to examine the behaviour of a particle in a field (e.g., test Coulomb’s law; replicate Millikan’s experiment or Rutherford’s scattering experiment; use a bubble or cloud chamber).
D3.3 Use field diagrams to explain differences in the sources and directions of fields, including, but not limited to, differences between near- Earth and distant fields, parallel plates and point charges, straight line conductors and solenoids.
Success Criteria:
- What are magnetic field lines?
- Describe the behaviour of two magnets as you bring (i) both north poles, (ii) both south poles, and (iii) opposite poles together.
- IF you continue to cut a bar magnet in half, can you isolate a north pole piece from the south pole?
- Describe how to draw magnetic field lines for a bar magnet.
- How can a compass help us determine the direction of the magnetic field lines?
- Distinguish between north geographic pole and north magnetic pole.
- Give some reasons as to what can cause Earth's magnetic field.
- State the principle of electromagnetism.
- Describe the right-hand rule for a straight conductor.
- Draw the magnetic field lines for a solenoid, and state the right-hand rule for a solenoid.
Time Allocation: 2 hours
Learning Activities:
Read pages 378 - 384 from Nelson 8.1
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Magnets and Compass
Ever wonder how a compass worked to point you to the Arctic? Explore the interactions between a compass and bar magnet, and then add the earth and find the surprising answer! Vary the magnet's strength, and see how things change both inside and outside. Use the field meter to measure how the magnetic field changes. |
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A straight wire carries an electric current symbolized by several little red spheres in motion (they move in the direction of conventional current, they are not electrons). Circular magnetic field lines are shown around the wire.
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A solenoid coil carries an electric current symbolized by several little red spheres in motion. A green arrow shows the direction of magnetic field inside the coil.
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A toroidal coil carries an electric current symbolized by several little red spheres in motion. A green arrow shows the direction of magnetic field inside the coil.
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Task:
Solve question 6 from Nelson 8.1 Review on page 385.
Reflect:
Compare and contrast the corresponding properties of gravitational, electric, and magnetic fields.
