20 Magnetism ENCOUNTER THE PHENOMENON Write the Encounter the Phenomenon question for this module. Use the “What I Know” column to list the things you know about the Encounter the Phenomenon question. Then list the questions you have about the Encounter the Phenomenon question in the “What I Want to Find Out” column. As you read the module, fill in the “What I Learned” column. W What I Want to Find Out Copyright © McGraw-Hill Education K What I Know Science Notebook • Magnetism 353 L What I Learned Magnetism 1 Understanding Magnetism REVIEW VOCABULARY conventional current Recall and write the definition of the Review Vocabulary term. conventional current NEW VOCABULARY Use your book to define each term. polarized polarized domain magnetic field magnetic flux domain electromagnetic force solenoid electromagnet magnetic field magnetic flux electromagnetic force electromagnet Science Notebook • Magnetism 354 Copyright © McGraw-Hill Education solenoid 1 Understanding Magnetism (continued) List four examples of objects you use frequently that rely on magnets to operate. Explain why the arrow on a compass points to geographical north. Copyright © McGraw-Hill Education Explain What happens to the poles of a magnet if you cut it in half? Draw S uppose you move a strong magnet so that it touches a piece of nickel wiring. In the top box, sketch arrows representing the domains in the wire before it touches the magnet. In the bottom box, sketch the domains after the wire has been touching the magnet for several hours. Before the nickel wire touches the magnet After the nickel wire touches the magnet Science Notebook • Magnetism 355 1 Understanding Magnetism (continued) Describe how the ocean floor records Earth’s magnetic field. Get It? Describe examples of how humans have used Earth’s magnetic poles through the centuries. Draw S ketch a diagram of magnetic field lines around a bar magnet. Science Notebook • Magnetism 356 Copyright © McGraw-Hill Education Describe what the magnetic field lines would look like for a magnet exerting a force on a nearby ferromagnetic material. Also describe the behavior of the domains in the ferromagnetic material. 1 Understanding Magnetism (continued) Get It? Cite Evidence Infer what the magnetic domains look like in the magnet shown on the first page of this module. Describe the relationship between the compass needle and the current-carrying wire in Oersted’s experiments. Get It? Summarize Oersed’s conclusion in your own words. Copyright © McGraw-Hill Education Explain the right-hand rule you can use to determine the direction of a magnetic field around a current-carrying wire. List four ways to increase the strength of an electric field produced by a solenoid. Explain the right-hand rule you can use to determine the north pole of a solenoid. Science Notebook • Magnetism 357 1 Understanding Magnetism (continued) Describe how a solenoid records information in a computer. CHECK YOUR PROGRESS 10. Electromagnets Explain how to construct an electromagnet. 11. Magnetic Fields What two things about a magnetic field can magnetic field lines represent? 13. Magnetic Fields Where on a bar magnet is the magnetic field the strongest? Science Notebook • Magnetism 358 Copyright © McGraw-Hill Education 12. Magnetic Forces Considering magnetic forces, how are forces at a distance explained? 1 Understanding Magnetism (continued) 14. Magnetic Fields Two current-carrying wires are close to and parallel to each other and have currents with the same magnitude. If the two currents were in the same direction, how would the magnetic fields of the wires be affected? How would the fields be affected if the two currents were in opposite directions? 15. Direction of the Field Describe how to use a right-hand rule to determine the direction of a magnetic field around a straight, current-carrying wire. 16. Electromagnets A glass sheet with iron filings sprinkled on it is placed over an active electromagnet. The iron filings produce a pattern. If this scenario were repeated with the direction of current reversed, what observable differences would result? Explain. Copyright © McGraw-Hill Education 17. Magnetic Domains Explain what happens to the domains of a temporary magnet when the temporary magnet is removed from a magnetic field. 18. Critical Thinking Imagine a toy containing two parallel, horizontal metal rods, one above the other. The top rod is free to move up and down. a.The top rod floats above the lower rod. When the top rod’s direction is reversed, however, it falls down onto the lower rod. Explain how the rods could behave in this way. b.Assume the toy’s top rod was lost and another rod replaced it. The new rod falls on top of the bottom rod no matter its orientation. What type of material is in the replacement rod? Science Notebook • Magnetism 359
