Study Notes: Grade 7 Technology, Magnetism

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1. Topic Overview

Main Concept/Theme:
Magnetism is a force of attraction or repulsion between objects due to their magnetic fields.

Key Learning Objectives:
– Understand what magnetism is and its importance.
– Learn about different types of magnets and their properties.
– Explore how magnets are used in everyday life and technology.
– Conduct experiments to observe magnetic forces and magnetic fields.
– Identify and understand the Earth’s magnetic field.

2. Key Terms and Definitions

  1. Magnet: An object that produces a magnetic field and can attract or repel certain metals.
  2. Magnetic Field: The invisible area around a magnet where magnetic forces are exerted.
  3. Poles: The ends of a magnet where the magnetic force is strongest; labeled as North (N) and South (S).
  4. Attraction: The force by which objects are drawn together.
  5. Repulsion: The force by which objects push away from each other.
  6. Magnetic Material: Materials that can be magnetized or attracted to a magnet (e.g., iron, nickel, cobalt).
  7. Non-Magnetic Material: Materials that are not affected by magnets (e.g., plastic, wood, glass).

3. Main Content Sections

A. What is Magnetism?

Magnetism is a physical phenomenon produced by the motion of electric charges, which results in attractive and repulsive forces between objects. Most commonly, magnetism can be observed in materials like iron, which can become magnetized and create their own magnetic fields.

B. Types of Magnets

There are three main types of magnets:
1. Permanent Magnets: Magnets that maintain their magnetic properties over a long time (e.g., fridge magnets).
2. Temporary Magnets: Magnets that act like permanent magnets when in a magnetic field but lose magnetism gradually when the field is removed.
3. Electromagnets: Magnets created by electric currents, often used in devices like speakers and motors.

C. Properties of Magnets

  • Polarity: Every magnet has two poles, North (N) and South (S). Opposite poles attract each other, while like poles repel each other.
  • Magnetic Force: The strength of a magnet varies depending on its size and material. Larger magnets usually have stronger magnetic forces.
  • Induction: Some materials can be magnetized by a magnetic field. When a non-magnetized piece of iron is placed next to a magnet, it temporarily becomes a magnet.

D. Uses of Magnets

Magnets are used in various applications:
– In households: Refrigerator magnets, door catches.
– In electronics: Speakers, microphones, and motors.
– In healthcare: MRI machines for imaging inside the body.
– In industrial applications: Separating magnetic materials from non-magnetic materials in recycling centers.

E. Earth’s Magnetic Field

  • Geomagnetic field: The Earth acts like a giant magnet with a magnetic field extending into space, which protects us from solar winds.
  • Compass: A device that uses a magnetized needle to indicate direction using the Earth’s magnetic field.

4. Example

Example 1:

Problem: What happens when you place the North pole of one magnet next to the South pole of another magnet?
Solution: The magnets will attract each other because opposite poles attract.

Case Study:

Exploring Magnetic Fields:
Conduct an experiment using iron filings and a bar magnet.
1. Place the bar magnet under a sheet of paper.
2. Sprinkle iron filings evenly on the paper.
3. Tap the paper gently.
4. Observe the pattern that forms, showing the magnetic field lines.

5. Summary

Magnetism is a fundamental force observed when objects are attracted or repelled by magnets. Magnets have two poles and create magnetic fields around them. The Earth itself is a giant magnet, which allows us to use compasses for navigation. Magnets come in different types and have numerous uses in everyday life and advanced technology.

6. Self-Assessment Questions


  1. What is a magnetic field?

    a. An area around a magnet where its forces can be felt.

    b. A type of metal.

    c. A physical state.



  2. How do the North and South poles of two different magnets interact?

    a. They repel each other.

    b. They attract each other.

    c. They do nothing.



  3. What kind of materials are attracted to magnets?



  4. Explain with examples.



  5. Describe one practical use of electromagnets.



  6. What happens when you place a piece of iron next to a strong magnet?


7. Connections to Other Topics/Subjects

  • Natural Sciences: Studying atomic structure and how electrons create magnetic fields.
  • Geography: Understanding the Earth’s magnetic field and how it affects navigation and animal migration.
  • Physical Science: Exploring the relationship between electricity and magnetism in electromagnets and motors.
  • History: Learning about the discovery of magnets and their evolving use in various technologies.

By understanding the basics of magnetism, students gain insight into a force that plays a vital role in both nature and technology.