Science · 5th Grade · Engineering Design and Innovation · Weeks 19-27

Magnets and Their Forces

Students will explore the properties of magnets and how magnetic forces interact with different materials.

• Common Core State Standards
• 3-PS2-3
• 3-PS2-4

About This Topic

Magnets offer a fascinating entry point into non-contact forces, which many 5th grade students find puzzling because the force acts without touching. Aligned to NGSS 3-PS2-3 and 3-PS2-4, this topic asks students to observe and explain that magnets can exert attractive and repulsive forces on certain materials, and that these forces are stronger at shorter distances. Students learn that magnets do not affect all materials equally: only certain metals respond to magnetic fields.

A key concept is understanding poles and how like poles repel while opposite poles attract. Students also discover that magnetic force can act through many materials, including paper, air, and plastic, which helps them build a broader model of forces that act at a distance. This connects well to students' prior knowledge of gravity as another non-contact force and helps them see patterns across physics concepts.

Because magnetic phenomena are both directly observable (through iron filings) and physically manipulable, active learning strategies are well-suited here. Hands-on comparative investigations and design challenges allow students to reason about invisible fields through tangible, observable evidence.

Key Questions

1. Explain how magnets attract and repel certain materials.
2. Compare the strength of different magnets and their fields.
3. Design a simple device that uses magnetic force to achieve a task.

Learning Objectives

• Explain how magnetic poles interact to cause attraction or repulsion.
• Compare the magnetic field strength of different bar magnets by observing their effect on paper clips at varying distances.
• Design and build a simple device, such as a magnetic levitation track or a magnetic fishing game, that utilizes magnetic force to perform a specific function.
• Identify materials that are attracted to magnets and classify them as magnetic or non-magnetic.
• Analyze how the distance between magnets affects the strength of their attractive or repulsive force.

Before You Start

Properties of Matter

Why: Students need to understand that different materials have different properties, including whether they are magnetic or not.

Forces and Motion

Why: Students should have a basic understanding of forces as pushes or pulls to grasp the concept of magnetic forces acting at a distance.

Key Vocabulary

Magnetism	A physical phenomenon produced by moving electric charges and magnetic dipoles, which results in attractive and repulsive forces.
Magnetic Pole	The two ends of a magnet, typically labeled North and South, where the magnetic force is strongest.
Magnetic Field	The area around a magnet where its magnetic force can be detected, often visualized with iron filings.
Attraction	The force that pulls opposite magnetic poles (North and South) toward each other.
Repulsion	The force that pushes like magnetic poles (North and North, or South and South) away from each other.

Watch Out for These Misconceptions

Common Misconception

All metals are magnetic.

What to Teach Instead

Students assume any shiny or heavy metal object will be attracted to a magnet. Testing aluminum, copper, and non-magnetized brass against iron helps correct this. Peer-led sorting activities where students categorize their test results as 'magnetic' or 'non-magnetic' make the distinction concrete and memorable.

Common Misconception

Magnetic force goes away when you cover the magnet.

What to Teach Instead

Students often believe that wrapping a magnet in paper or plastic blocks its force. Investigations that test force through paper, fabric, and water show that magnetic force acts through many media. Having students measure whether the paper clip is still attracted through 1, 2, and 5 sheets of paper gives quantitative evidence against this idea.

Common Misconception

Stronger magnets always lift more objects.

What to Teach Instead

Students conflate 'more force' with 'lifting more items' without accounting for the mass and surface area of the objects. Graphing magnetic strength at different distances makes this relationship more precise and helps students see that the number of objects lifted is a function of both magnet strength and object properties.

Active Learning Ideas

Inquiry Circle: Testing Magnetic Strength at Distance

Student groups use a horseshoe magnet and a bar magnet to test how many paper clips each lifts at distances of 1 cm, 2 cm, and 5 cm. They record results in a shared data table, graph the relationship between distance and strength, then compare findings across groups.

40 min·Small Groups

Think-Pair-Share: What Will a Magnet Attract?

Students predict which objects in a bag (penny, iron nail, aluminum foil, steel paper clip, plastic button, wooden stick) will be attracted to a magnet. They discuss predictions with a partner, test each object, then reconcile their predictions with results in a whole-class discussion focused on what these materials have in common.

25 min·Pairs

Design Challenge: Magnetic Sorter

Groups design a simple device using magnets, cardboard, string, and cups that can separate a mix of iron nails and aluminum paper clips without touching either material by hand. Groups present their designs, explain how magnetic force is applied, and evaluate which approach was most efficient.

50 min·Small Groups

Gallery Walk: Iron Filing Field Maps

Each group places a bar magnet under paper and sprinkles iron filings to create a field map showing the magnetic field pattern. Maps are posted around the room. Students tour with sticky notes to identify poles, note where the field is strongest, and compare field shapes across different magnets.

30 min·Small Groups

Real-World Connections

• Engineers use magnetic levitation (maglev) trains, which float above tracks using powerful magnets, to achieve high speeds with minimal friction, as seen in Shanghai.
• In hospitals, MRI machines use strong magnetic fields to create detailed images of the inside of the human body, helping doctors diagnose illnesses without surgery.
• Many household appliances, like refrigerators and vacuum cleaners, incorporate magnets in their motors and door seals for essential functions.

Assessment Ideas

Exit Ticket

Provide students with two bar magnets. Ask them to draw and label how they would arrange the magnets to create attraction, and then how they would arrange them to create repulsion. Include a sentence explaining why each arrangement works.

Quick Check

Present students with a collection of objects (e.g., paperclip, coin, plastic toy, iron nail, wooden block). Ask them to predict which objects will be attracted to a magnet, then test their predictions and record the results, classifying each object as magnetic or non-magnetic.

Discussion Prompt

Pose the question: 'Imagine you have a magnet and a metal door. How could you tell if the door is made of a material that a magnet will attract without touching the door itself?' Guide students to discuss the concept of magnetic fields acting at a distance.

Frequently Asked Questions

How do I explain magnetic fields to 5th graders without advanced physics?

Focus on what students can observe. Iron filings on paper visibly trace the field lines around a magnet, giving students a concrete image of an invisible concept. Using the phrase 'area of influence' instead of 'field' is more intuitive and still scientifically accurate for this level.

Why don't all metals stick to magnets?

Only certain metals, primarily iron, cobalt, and nickel, are strongly attracted to magnets. Most common metals like aluminum, copper, and gold have atomic structures that do not align with magnetic fields. At 5th grade, it is enough to distinguish 'magnetic materials' from 'non-magnetic materials' through empirical testing.

What is the difference between attract and repel?

When two different poles face each other (north and south), they pull together and attract. When the same poles face each other (north-north or south-south), they push apart and repel. Students can explore this directly by flipping two bar magnets end-to-end and feeling the push or pull. The physical experience makes the concept stick in a way that diagrams alone cannot.

How does active learning help students understand magnetic forces?

Magnetic forces are counterintuitive because they act at a distance with no visible mechanism. Inquiry-based investigations where students predict, test, and revise their models are far more effective than explanation alone. When predictions are contradicted by evidence, collaborative discussion helps students build a more accurate mental model through their own reasoning.