Section+2-1+Forces+and+Fields

__Objectives__: Describe the forces magnets produce Identify the north and south poles of a magnet Explain the role of magnetic fields

__Vocabulary Words__: Magnetic poles- Magnetic field-

More than 2000 years ago the ancient observed that a type of black ______________,__ now called or magnetite, could attract pieces of __.__ A free-moving lodestone was the first magnetic ________________. How did Chinese traders and soldiers make a compass with lodestone?

Which century were European explorers using compasses to navigate at sea? The ends of a magnet are called the magnetic _. The end pointing north is called the _-_ pole. Two north poles _each other. Two south poles ___each other. A north and a south pole will__ __each other. As the poles are moved__ _ __together, the force between them becomes__ __. No matter how many times you break a magnet, you are left with more__ __magnets. No one has ever found an__ _ __magnetic pole. Each iron filing acts like a tiny__ _ __magnet. When you bring unlike poles near each other the filings line up to reveal that the__ _ __links the two poles.__

Computer Question: __1. Magnets are often made up of alloys. What are alloys?__

Check Your Understanding__ 1. Figure 2-5 (a) shows the field around a doughnut-shaped magnet. Where are thsi magnet's poles? How would you identify the magnet's north and south poles?

2. Figure 2-5 (b) shows five doughnut-shaped magnets on a pencil. Suppose the lower pole on the bottom magnet is the north pole. Identify both poles on each of the four magnets.

3. What is the relationship between the magnetic force and the magnetic field?

4. Apply. If a magnetic compass needle points north, what is the actual polarity of the Earth's northern pole? Explain.