Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnetism Table of Contents Section 1 Magnets and Magnetic Fields Section 2 Magnetism from Electric Currents Section 3 Electric Currents from Magnetism Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Objectives Recognize that like magnetic poles repel and unlike poles attract. Describe the magnetic field around a permanent magnet. Explain how compasses work. Describe the orientation of Earth’s magnetic field. Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer 1.Magnets are a part of daily life. Most of us use them without thinking about it. Name five places that you use magnets. 2.If you had two bar magnets and you touched the end of one bar magnet to the end of the other bar magnet, what are the two possible outcomes? If you rotated one of the bar magnets 180°, what are the two possible outcomes? 3.Explain why a compass is a useful tool for navigation. Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Bellringer, continued 4.On Earth, there is the magnetic N pole and the geographic North Pole. According to the picture above, are they located at the same geographic location? Where do you think the magnetic S pole is located? Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnets Some materials can be made into permanent magnets. Although a magnetized piece of iron is called a “permanent” magnet, its magnetism can be weakened or even removed. Iron is a soft magnetic material. It is easily magnetized. It tends to lose its magnetic properties easily. Cobalt is a hard magnetic material. It more difficult to magnetize. Once magnetized, it doesn’t lose its magnetism easily. Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnetic Materials Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnets, continued Magnets exert magnetic forces on each other. Like poles repel, and opposite poles attract. A magnetic pole is one of two points, such as the ends of a magnet, that have opposing magnetic qualities. Magnets have a pair of poles, a north pole and a south pole. It is impossible to isolate a south magnetic pole from a north magnetic pole. Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnetic Poles Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnetic Fields Magnets are sources of magnetic fields. Magnetic force is a field force. When magnets repel or attract each other, it is due to the interaction of their. A magnetic field is a region where a magnetic force can be detected. Magnetic field lines are used to represent a magnetic field. The magnetic field gets weaker with distance from the magnet. Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnetic Fields Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnetic Field Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Magnetic Fields, continued Compasses can track magnetic fields. A compass is a magnet suspended on top of a pivot so that the magnet can rotate freely. A compass aligns with Earth’s magnetic field. Earth’s magnetic field is like that of a bar magnet. Earth’s magnetic field has changed direction throughout geologic time. Earth’s magnetic poles are not the same as its geographic poles. Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Earth’s Magnetic Field Section 1 Magnets and Magnetic Fields Chapter 17

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Earth’s Magnetic Field Section 1 Magnets and Magnetic Fields Chapter 17