TOPIC: Force and motion AIM: How do magnets behave? DO NOW:

Magnets have been known for centuries. The Chinese and Greeks knew about the “magical” properties of magnets. The ancient Greeks used a stone substance called “magnetite.” They discovered that the stone always pointed in the same direction. Later, stones of magnetite called “lodestones” were used in navigation.

Force of attraction or repulsion Due to electron arrangement Magnetism

Natural Magnet –Magnetite (lodestone)

Materials attracted to magnets: Iron, nickel, cobalt, steel

2 ends North & south NS Poles

ATTRACTION –North & South attract

REPULSION –N repels N –S repels S

Law of Poles

Like repels like… Opposites attract!

Like poles (repel)

Unlike poles (attract)

Area around magnet where magnetic forces act Strongest at poles Decreases as distance from magnet increases MAGENTIC FIELD

Direction: North  south

Let’s summarize… 1.Describe magnetism. 2.What causes magnetism? 3.Describe the poles of a magnet. 4.Describe the magnetism between two alike poles. 5.Describe the magnetism between two unlike poles. 6.Describe what a magnetic field is. 7.Where is the magnetic field the strongest? 8.What happens to the magnetic field when the distance from magnet increases?

What will happen to the force between the 2 magnets if they are pulled farther apart? 1.The force would be stronger. 2.The force would be weaker. 3.The force would stay unchanged. 4.The force would reverse poles.