1) Earth itself acts like a giant magnet with a north and south pole that generates a magnetic field extending 50,000 miles into space, allowing compasses to function by pointing towards Earth's magnetic north pole. 2) A compass needle is magnetic and orients itself towards the north-seeking pole of Earth's magnetic field, though it may be affected inside steel buildings or ships due to magnetic attraction between the needle and nearby steel. 3) Magnetic fields surround all magnets and are represented by magnetic lines of force showing the direction and strength of the magnetic force, with lines closest together at the poles where the force is strongest.

1. Magnetism

2. Science Background : Earth itself is like a giant magnet. The magnetic field of Earth extends about 50,000 miles out into space. Earth has a north and south magnetic pole.

3. Compass : A compass’s needle is a magnetic. The north pole of a compass, or any other magnet, is really a north-seeking pole. Why do you think a compass might not work correctly in a large steel building or on a steel ship?

4. Answer: Magnets attract steel objects. The compass needle used inside a steel building or ship would be affected by the closet steel object and not necessarily point in a northerly direction.

5. Warm-Up Activity: Spread some paper clips on a table. Lower a bar magnet over the paper clips. Where do most of the paper clips stick to on the magnet. WHY?

6. Identifying A Magnetic Field: A magnetic field surrounds all magnets. Magnetic Field : An area around a magnet in which magnetic forces can act. The magnetic forces will attract or repel other magnets.

7. Magnetic Field …(p. 351) You cannot see magnetic fields, but you can see their effects. Lines of Force : Lines that show a magnetic field. Lines of force are caused by the magnetic field and show the field. The lines of force reach around the magnet from one pole to another. The lines are closet together near the poles. Where the field is the strongest and the forces are greatest.

8. The Earth as a Magnet : The Earth itself is a giant bar magnet. The Earth’s magnetic poles are located near the geographic north and south poles. The Earth’s magnetism allows compasses to work.

9. Earth As a Magnet Continued … Page. 352 The north magnetic pole of Earth attracts the north pole of a compass. This happens because Earth’s north magnetic pole is actually like the south pole of a magnet. It is called the north magnetic pole because it is located near the geographic North Pole.

10. Lesson 2 Review: 1.) What is a magnetic field? 2.) What pattern is made by magnetic lines of force around a bar magnet? 3.) How does a compass work? 4.) Where are magnetic lines of force closest?