Exploring Magnets · Lesson 5 of 6
Using Magnets in Clever Ways
“Apply magnetic attraction and repulsion to toys, retrieval tasks, safe storage, and real-world extensions.”
• Apply magnetic attraction and repulsion to simple toys and practical tasks. • Explain how magnets can move some objects without direct contact. • Recognise common ways in which North and South poles may be marked. • Describe safe handling and storage practices for magnets. • Connect magnet shape and strength to practical uses without changing the chapter's core ideas.
Using Magnetic Force Without Touching
The previous lesson showed that magnetic effects can act across a small gap and through thin non-magnetic materials. That makes magnets useful for moving or retrieving magnetic objects without direct contact. The chapter turns this idea into several playful demonstrations.
A magnet below a cardboard maze can guide a steel ball above it. A steel paper clip that has fallen into water can be attracted toward a magnet without putting fingers into the water. In both cases, the object responds even though the magnet does not need to touch it first.
The chapter also suggests making a magnetic garland, another simple demonstration in which magnetic attraction is used as part of a playful arrangement. These examples are valuable because they turn an invisible interaction into visible movement.
Turning Repulsion into Motion
Repulsion can also produce visible motion. If two small toy cars carry magnets with like poles facing one another, bringing the cars close can make them move apart. The motion is a direct application of the same like-poles-repel rule studied earlier.
Problem
Two matchbox cars each carry a bar magnet. The facing ends are both North poles. What should happen when the cars are brought close and released?
- 1.The facing poles are the same type: North faces North.
- 2.Like poles repel.
- 3.The magnetic interaction therefore pushes the cars away from each other if they are free to move.
How Poles May Be Marked
Manufacturers do not always mark magnets in exactly the same way. Some magnets are labelled N and S. In others, the North pole may be indicated by a white dot or by a chosen colour. A common classroom convention is to colour one pole red and the other blue, but the label or test is more reliable than assuming that every magnet uses the same colour scheme.
Colour conventions can vary. If the pole is not clearly labelled, use a known magnetic test or the north-south alignment of a freely suspended magnet rather than guessing from paint.
Taking Care of Magnets
Magnets should be handled carefully because rough treatment and heating can weaken their useful magnetic behaviour. The chapter specifically cautions against heating, dropping or hammering magnets and recommends keeping them away from devices such as mobile phones and remote controls.
For storing a pair of bar magnets, the chapter shows them placed with unlike poles on the same side, a wooden piece between them, and soft iron pieces across the ends. The arrangement is meant to help preserve the magnets while they are not in use.
Comparing Magnets and Exploring Different Shapes
Magnets can differ in how strongly they attract a set of identical steel pins or U-clips. A fair comparison keeps the objects and testing method similar, then counts how many pins each magnet can lift. Different results suggest that the magnets do not all have the same magnetic strength.
Use three or four different magnets with the same type of steel pins or U-clips. Let each magnet pick up as many as it can under similar conditions. Count and compare. The number lifted is an observational way to compare their performance in that setup.
Magnets are also made in many shapes, including bar, disc, cylindrical, ring and spherical forms. Shape is chosen to suit the way the magnet will be fitted or used, but changing the shape does not remove the basic rule that poles occur in pairs.
Learning Further
The chapter suggests extending these ideas through projects rather than introducing a new theory. A 'hopping frog' toy uses several ring magnets arranged with alternating pole directions. The same attraction-and-repulsion ideas can also lead students to investigate magnetic levitation trains, reasons for different magnet shapes, and selected uses of magnets in medicine.
Fix ring magnets along a scale in an alternating pole arrangement. Attach a ring magnet to a paper frog mounted on a flexible strip. Sliding the frog over the arranged magnets can make it move up and down as it encounters changing magnetic interactions. Build this only with teacher guidance and secure all small magnets carefully.
The chapter invites you to investigate Maglev trains and uses of magnets in medicine. These are extension topics: the important link is that real technologies make purposeful use of magnetic interactions.
Quiz
How can a magnet help move a steel ball through a cardboard maze?
Two toy cars have North poles facing one another. What is the expected motion?
Which is the safest way to identify an unmarked pole?
Which action does the chapter advise against when caring for magnets?
Why might manufacturers make magnets in different shapes?
Practice Problems
- Explain how a magnet could help retrieve a steel paper clip from water without putting your fingers into the water.
- Predict what happens if two toy cars carry magnets with like poles facing each other. Then predict the result if one magnet is reversed.
- List three ways a magnet's poles might be marked and explain why colour alone should not be trusted when markings are unclear.
- Describe the storage arrangement for a pair of bar magnets shown in the chapter.
- Design a fair test to compare which of three magnets can lift the greatest number of identical steel pins.
- Choose one magnet shape—bar, disc, cylindrical, ring or spherical—and suggest a situation where that shape could be convenient.
- Explain how the hopping-frog project depends on attraction and repulsion rather than on a new kind of magnetic force.
Key Takeaways
• Magnets can move magnetic objects without first touching them, and their effects can act through thin non-magnetic materials. • Like-pole repulsion can be used to produce motion in simple toys. • Pole markings vary, so use labels or magnetic tests rather than colour alone. • Magnets should be protected from heating, dropping and hammering and stored carefully. • Magnets come in many shapes and strengths because different designs suit different uses, while North and South poles still occur in pairs.