Permanent Magnets and Magnetic Fields

Active learning helps students visualize the invisible properties of magnets and magnetic fields. Hands-on investigations provide direct evidence of abstract concepts like field lines and polarity, making abstract ideas concrete and memorable.

• Year 11
• Physics
• 3 activities
• 20 min–50 min

Learning Objectives

1. Identify the two types of magnetic poles and predict the force between like and unlike poles.
2. Map the direction and pattern of magnetic field lines around a bar magnet and a horseshoe magnet using a plotting compass.
3. Construct a visual representation of a magnetic field using iron filings and explain the significance of the pattern observed.
4. Compare and contrast the magnetic field patterns of a bar magnet and a horseshoe magnet.

Inquiry Circle

⏱ 50 min·Small Groups

Inquiry Circle: The Electromagnet Strength Test

Teams build their own electromagnets and systematically vary the number of coils and the current. They measure the strength by the number of paperclips lifted, plotting their results to find the mathematical relationship between the variables.

Prepare & details

Explain the concept of magnetic poles and their interactions.

Facilitation Tip: During the Electromagnet Strength Test, circulate with a multimeter to help groups measure current accurately and troubleshoot weak connections.

Setup: Groups at tables with access to source materials

Materials: Source material collection, Inquiry cycle worksheet, Question generation protocol, Findings presentation template

• Analyze
• Evaluate
• Create
• Self-Management
• Self-Awareness

Gallery Walk

⏱ 40 min·Small Groups

Gallery Walk: Mapping the Invisible

Students use plotting compasses to map the magnetic field around different configurations: a single bar magnet, two attracting magnets, and a solenoid. They must leave their 'maps' at stations for other groups to critique and improve.

Prepare & details

Analyze the pattern of magnetic field lines around different types of magnets.

Facilitation Tip: For the Gallery Walk, assign each group a different magnet or solenoid setup so the room becomes a full exploration of field patterns.

Setup: Wall space or tables arranged around room perimeter

Materials: Large paper/poster boards, Markers, Sticky notes for feedback

• Understand
• Apply
• Analyze
• Create
• Relationship Skills
• Social Awareness

Think-Pair-Share

⏱ 20 min·Pairs

Think-Pair-Share: The Magnetic Scrap Yard

Students are shown a video of a scrap yard crane. They must discuss with a partner why an electromagnet is used instead of a permanent magnet and explain the physics of how the crane 'drops' the metal, then share with the class.

Prepare & details

Construct a magnetic field map using a compass and iron filings.

Facilitation Tip: During the Magnetic Scrap Yard discussion, provide labeled metal samples and ask students to justify their sorting choices using magnetic properties.

Setup: Standard classroom seating; students turn to a neighbor

Materials: Discussion prompt (projected or printed), Optional: recording sheet for pairs

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Teaching This Topic

Teach magnetic fields by starting with tangible experiences—students should first feel the pull of a magnet before drawing lines on paper. Avoid over-relying on diagrams early on, as field lines are a representation, not a physical reality. Research shows students need multiple representations (3D viewers, filings, compasses) to build a strong mental model of magnetic fields.

What to Expect

Students will confidently map magnetic fields, explain how electromagnets work, and correct common misconceptions about magnetic materials. They should use evidence from investigations to support their reasoning about field direction and strength.

Watch Out for These Misconceptions

Common Misconception

During Gallery Walk: Mapping the Invisible, watch for students who draw field lines as starting at one pole and ending at the other.

What to Teach Instead

Use the 3D magnetic field viewer with iron filings in oil during the gallery setup to show students the continuous loops of the field. Have them trace the loops with their fingers to feel the field’s three-dimensional nature.

Common Misconception

During Think-Pair-Share: The Magnetic Scrap Yard, watch for students who assume all metals are magnetic.

What to Teach Instead

Provide a labeled tray of metal samples (aluminum, copper, brass, steel) and ask students to test each with a bar magnet. Have them record which materials are attracted and discuss why only ferromagnetic materials respond.

Assessment Ideas

Quick Check

After Collaborative Investigation: The Electromagnet Strength Test, provide a diagram of two bar magnets. Ask students to draw field lines for North-to-South and North-to-North arrangements, labeling directions. Collect responses to identify any misconceptions about field line behavior.

Exit Ticket

After Gallery Walk: Mapping the Invisible, give students an index card. On one side, have them sketch a horseshoe magnet’s field lines with arrows. On the other, ask them to explain why iron filings form visible patterns, using evidence from the activity.

Discussion Prompt

During Think-Pair-Share: The Magnetic Scrap Yard, pose the question: 'If you broke a magnet in half, what would happen to its poles?' Have students discuss in pairs, then share with the class. Listen for explanations referencing the continuous nature of magnetic fields and the presence of both poles in each piece.

Extensions & Scaffolding

• Challenge students to design a simple electromagnet that can lift 20 paperclips, documenting their coil turns and current settings.
• Scaffolding: Provide pre-labeled diagrams for students to match with field line sketches before they draw their own.
• Deeper exploration: Have students research how MRI machines use strong magnetic fields and present their findings to the class.

Key Vocabulary

Magnetic Pole	The two ends of a magnet, designated North and South, where the magnetic force is strongest. Like poles repel each other, and unlike poles attract.
Magnetic Field	The region around a magnet where a magnetic force can be detected. It is represented by invisible lines of flux.
Magnetic Field Lines	Imaginary lines used to represent the strength and direction of a magnetic field. They emerge from the North pole and enter the South pole.
Iron Filings	Small particles of iron that align themselves with the magnetic field lines when sprinkled around a magnet, making the field visible.
Plotting Compass	A small magnetic compass used to trace the direction of magnetic field lines by observing where its North pole points at different locations around a magnet.