Understanding Magnetism
Explore the invisible forces that attract, repel, and protect our planet
Key Concept: Magnetism is a force of attraction or repulsion that acts at a distance. It's caused by the motion of electric charges and is fundamental to how our world works.
1. Magnetic Fields
Magnetic Poles
Every magnet possesses two distinct poles: a North (N) pole and a South (S) pole. Like poles repel, opposite poles attract.
Pole Interaction Simulator
Select pole types to see how they interact
Magnetic Field Lines
Magnetic field lines always originate from the North pole and terminate at the South pole, creating continuous loops.
Field Strength
The strength of a magnetic field can be inferred from the density of field lines:
- Strong field: Lines are close together
- Weak field: Lines are spread apart
At the Poles
The magnetic field is strongest at the poles because:
- Field lines are most dense
- Maximum magnetic force
2. Magnetic Materials
Ferromagnetic Materials
Iron, nickel, and cobalt exhibit strong magnetic properties.
Permanent vs. Temporary Magnets
Permanent Magnets
- Maintain magnetism over time
- Made from hard magnetic materials
- Examples: Alnico, ferrite magnets
- Used in speakers, motors
Temporary Magnets
- Magnetic only in magnetic field
- Made from soft magnetic materials
- Examples: Iron nail, paperclips
- Used in electromagnets
Quick Game: Click on materials to sort them!
Click to test:
3. The Earth's Magnetic Field
Geographic North
- True north pole
- Earth's rotation axis
- Fixed location
- Where all longitude lines meet
Magnetic North
- Where compass points
- Moves over time
- Currently in Canada
- Actually a south magnetic pole!
Fun Fact: The Earth's magnetic North Pole is actually a magnetic SOUTH pole! This is why the north end of a compass needle points toward it (opposites attract).
Magnetic Declination
The angle between geographic north and magnetic north varies depending on your location.
The Magnetosphere
The Earth's magnetic field creates a protective bubble called the magnetosphere that deflects solar wind.
What beautiful phenomenon is caused by solar wind interacting with Earth's magnetic field?
4. Conservation of Magnetic Flux
Magnetic field lines cannot simply "stop" - they must always form closed loops. For every field line that exits a magnet, there must be a corresponding line that returns to it.
Match the Terms
Complete the Sentence
Like poles , opposite poles .
Magnetism Word Search
Find these words: POLE, FIELD, NORTH, SOUTH, IRON, MAGNET
Build the Formula
Click the pieces in the correct order to form the magnetic force formula:
Test Your Understanding
1. What happens when you bring two North poles together?
2. Which materials are ferromagnetic?
3. Where is Earth's magnetic field strongest?
Key Terms
Key Takeaways
- Like poles repel, opposite poles attract
- Magnetic field lines form continuous loops from North to South
- Iron, nickel, and cobalt are ferromagnetic materials
- Earth acts like a giant magnet with magnetic north near geographic south
- Magnetic flux is always conserved - field lines never end
