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Discovering that every magnet has two special ends called poles.
Have you ever noticed that a magnet seems to have 'super strength' at its very tips, but almost no power in the middle? Why are the ends so much more powerful than the center?
Magnets have two special spots where their invisible pulling power is the strongest. These spots are called poles. Every magnet has exactly two: a North Pole (often colored red or marked with an ) and a South Pole (often colored blue or marked with an ). If you try to pick up metal paperclips, you will see they all rush to the ends! The middle of the magnet is much weaker than the poles.
Quick Check
Where is a magnet's pulling power the strongest?
Answer
At the poles (the ends).
Here is a magnet secret: you can never have just one pole. Imagine you have a long bar magnet and you snap it right in the middle. You might think you now have one North piece and one South piece. But nope! Each new piece instantly grows a new pole. Now you have two smaller magnets, and both have a North and a South pole. Even if you ground a magnet into tiny dust, every single speck would still have two poles!
1. Start with 1 bar magnet (it has 2 poles: and ). 2. Break it into 2 pieces. 3. Count the poles: Each piece now has its own and . 4. Total poles now = poles!
Quick Check
If you break a magnet into 10 tiny pieces, how many poles will each tiny piece have?
Answer
Each piece will have 2 poles (a North and a South).
Magnets come in many shapes, but the rule stays the same. A bar magnet has poles at the opposite flat ends. A horseshoe magnet is just a bar magnet bent into a 'U' shape, which brings the North and South poles right next to each other! Ring magnets (which look like donuts) usually have one pole on the top flat face and the other pole on the bottom flat face.
Imagine you have a horseshoe magnet with no labels. 1. Hold a paperclip near the curved 'U' part. It doesn't stick well. 2. Move the paperclip to the two flat tips at the end of the 'U'. 3. The paperclip snaps on tight! These two tips are the North and South poles.
You have a flat ring magnet lying on a table. 1. If the top side is the North pole, where is the South pole? 2. Answer: It is on the bottom side, touching the table! 3. Even though it is a circle, it still has two opposite sides that act as the two poles.
What are the names of the two poles on a magnet?
Where would you find the poles on a horseshoe-shaped magnet?
If you break a magnet in half, you get one piece that is only North and one piece that is only South.
Review Tomorrow
In 24 hours, try to remember: If you had a magnet the size of a grain of sand, how many poles would it have?
Practice Activity
Find a magnet at home (like a fridge magnet). Use a small metal object like a paperclip to 'feel' where the pull is strongest. Can you find the two poles?