Lesson 7 — Electric and Magnetic Fields

Summary

Learners explain electric and magnetic fields and how they interact to produce forces and currents. They trace the chain — moving charge → field → force → current — and see how it makes motors and generators work.

Objectives

• Explain electric and magnetic fields and how they interact to produce forces and currents. (D06.S3.08.02)

Connection

Hold two magnets near each other and feel the invisible push or pull between them — a force that works across empty space. That invisible region is a field, and it is not just a curiosity: the light in your room, the hum of a fan, and the charging of a phone all depend on the dance between electric and magnetic fields. Today you learn to name that dance and see where it powers your life.

Materials

• Fields sheet
• Field cards

Preparation

• Copy the fields sheet and field cards.
• Retrieval: from Grade 5, recall magnets attract and repel and act at a distance; from Grade 6, recall that a circuit carries a current.

Facilitator note

This lesson is written to the learner (“you”). The ideas to land: (1) a field is a region where a force acts without touching — an electric field surrounds electric charge, a magnetic field surrounds a magnet; (2) an electric current is moving charge; (3) a current in a wire produces a magnetic field around it, and a changing or moving magnetic field can push charge to make a current — that is the interaction; (4) this link is the basis of motors (current → force → motion) and generators (motion → changing field → current). Model the chain once (worked example, S-011), using the compass-and-wire demo if available (S-360). The technology lens: generators and motors run the modern world — but note that the principle is universal and was discovered and applied worldwide, not in one place. The egalitarian lens: electricity is not yet available to everyone — hundreds of millions still live without reliable power, and access is a matter of justice, not luck (S-052). The critical-thinking lens: “current makes a field, and a changing field makes a current” is a precise, checkable claim, not a story. The global lens: Earth itself has a magnetic field that guides compasses and has helped travelers and sailors find their way for centuries — the magnetic compass was first developed in China and then spread along the world’s trade and sea routes (S-187). Keep the physics precise and cite the electromagnetism source (S-360); hold the field as a model with strong evidence, not a visible thing you can point to (philosophy §11).

Procedure

1. Recall (5 min). From Grade 5: what do magnets do, and how can they act without touching? From Grade 6: what flows in a circuit? Today we connect the two.
2. Meet the field (10 min). A field is a region where a force acts at a distance. An electric field surrounds electric charge; a magnetic field surrounds a magnet. A current is moving charge.
3. Watch them interact (12 min). A current in a wire produces a magnetic field around it — a compass needle near the wire swings. And a moving or changing magnetic field can push charge to make a current. Electric and magnetic fields are two faces of one interaction.
4. Trace the chain (10 min). Arrange the field cards: moving charge → field → force → current. Then two machines: a motor turns current into motion; a generator turns motion into current.
5. Label the sheet (8 min). On the fields sheet, label the wire, the current, the field lines, and the compass. Write one sentence for each machine.
6. Close (5 min). Share one way electric and magnetic fields touch your day. An invisible field powers much of the world — and not everyone yet shares in it.

Differentiation

• Support: Provide the chain pre-ordered and ask learners to match each card to its meaning.
• Extension: Explain why an electromagnet can be switched on and off, and name one place that is useful (a crane, a door lock, a speaker).

Assessment

• Formative (observation): Can the learner explain a field, and how current makes a magnetic field and a changing field makes a current?
• Portfolio artifact: The labeled fields sheet, kept in the portfolio.

Home connection

Look around home for anything with a motor or that plugs in. Ask: where is a current flowing, and where is a field doing work?

Resources

• On electromagnetism, currents, and fields: BBC Bitesize (KS3), “Electromagnetism,” https://www.bbc.co.uk/bitesize/topics/zrvbkqt/articles/z7922v4 (S-360).
• On magnets acting at a distance and compasses: BBC Bitesize (KS2, NI), “What is a magnet?,” https://www.bbc.co.uk/bitesize/articles/zpvcrdm (S-187).
• On light and energy access: Our World in Data, “Light at Night,” https://ourworldindata.org/light-at-night (S-052).
• On explicit instruction and worked examples: Kirschner, Sweller & Clark (2006), https://doi.org/10.1207/s15326985ep4102_1 (S-011).