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Supplemental Worksheets Name Date Class Quick Vocabulary Lesson 1 Lesson 2 electric conductor material in which charge definite quantity of electric charges easily move electric discharge loss of an electric circuit closed, or complete, unbalanced electric charge path in which an electric current flows electric field invisible region around a charged object where an electric force is applied electric force a force that two electrically charged objects apply to each other electric insulator material in which electric charges cannot easily move electrically charged having an unbalanced amount of positive charge or negative charge electrically neutral having equal Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. electricity amounts of positive charge and negative charge electric current movement of electrically charged particles electric resistance measure of how difficult it is for an electric current to flow in a material generator machine that transforms mechanical energy to electric energy light electromagnetic radiation you can see voltage amount of energy used to move one coulomb of electrons through the circuit nucleus basic or essential part; core Electricity and Magnetism 3 Name Date Class Quick Vocabulary Lesson 3 electromagnet temporary magnet made with a current-carrying wire coil wrapped around a magnetic core magnet an object that attracts iron and other materials that have magnetic qualities similar to iron magnetic domain region in a magnetic material in which the magnetic fields of the atoms all point in the same direction magnetic force push or pull a magnetic field applies to either a magnetic material or an electric current magnetic material material that is attracted to a magnet Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 4 Electricity and Magnetism Name Date Class Lesson Outline LESSON 1 Electric Charges and Electric Forces A. Electric Charges 1. Each atom contains a core called the . a. The nucleus is made up of smaller particles called protons and . b. Atoms also contain , which move around the nucleus. c. Protons and have electric charge. 2. Electric charges are either positive or . a. Protons have charge; electrons have charge. b. Atoms are because they have equal amounts of positive and negative charges. c. Electrically neutral objects become when they gain or lose electrons. d. An object that loses electrons becomes charged. e. An object that gains electrons becomes charged. is the loss of unbalanced electric charge by an object. a. Some electric discharge occurs , for example, maybe you have noticed that static cling lasts longer on dry days. b. A lightning strike is an example of an electric discharge that occurs 4. . move at different rates through different materials. a. Materials through which electric charge moves easily are called . b. Materials through which electric charge cannot move easily are called 10 . c. Examples of insulators include plastic, wood, and . d. Some of the best conductors of electric charge are . Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3. Name Date Class Lesson Outline continued B. Electric Fields and Electric Forces 1. An electric charge is surrounded by a(n) . a. Charged objects do not have to to exert a force on each other. b. Scientists know that there is a(n) region around charged objects that apply an electric force. 2. is the force an electric field applies to another charged object. 3. The electric force between two charged objects depends on the of charge on the objects. a. Two negative objects each other away. b. Two positive objects each other away. c. A positive object and a negative object each other Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. together. Electricity and Magnetism 11 Name Date Class Content Practice A LESSON 1 Electric Charges and Electric Forces Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term is used only once. 1. refers to a particle that has equal amounts of positive charge and negative charge 2. refers to an object that has an unbalanced amount of positive charge or negative charge 3. refers to an object that has more positive charge than negative charge A. electric conductor B. electric field C. electric force D. electric discharge E. electrically charged F. electrically neutral 4. refers to an object that has more negative charge than positive charge 5. the loss of an unbalanced electric charge G. electric insulator H. negatively charged I. positively charged 6. a material in which electric charges cannot easily move 7. a material in which electric charges easily move Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 8. the force that two electrically charged objects apply to each other 9. the invisible region around a charged object where an electric force is applied Electricity and Magnetism 13 Name Date Content Practice B Class LESSON 1 Electric Charges and Electric Forces Directions: Distinguish between the terms in each of the following pairs. 1. atom, nucleus 2. proton, electron Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3. positively charged, negatively charged 4. electric insulator, electric conductor 14 Electricity and Magnetism Name Date Class Key Concept Builder LESSON 1 Electric Charges and Electric Forces Key Concept How do objects become electrically charged? Directions: Circle the term in parentheses that correctly completes each sentence. 1. (Atoms/Electric charges) are the tiny particles that make up all the matter around you. 2. An atom has a(n) (nucleus/electron) that is made up of two kinds of smaller particles called protons and neutrons. 3. (Electrons/Protons) move around an atom’s nucleus. 4. (Protons/Neutrons) do not have electric charge. 5. (Electrons/Neutrons) have electric charge. objects become electrically charged. 7. Whether an object becomes positively or negatively charged depends on the material it (repels/contacts). 8. Electrons transfer from a material that holds electrons (more/less) tightly to a material that holds electrons (more/less) tightly. 9. Wool does not hold electrons as tightly as rubber, so when a wool sweater and a rubber balloon are rubbed together, electrons transfer from the (sweater/balloon) to the (sweater/balloon). 16 Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 6. When (protons/electrons) transfer from one electrically neutral object to another, the Name Date Key Concept Builder Class LESSON 1 Electric Charges and Electric Forces Key Concept How do electrically charged objects differ? Directions: Complete the concept map with the correct term or statement from the word bank in the space provided. Each term or statement is used only once. An object has equal amounts of protons and electrons. An object has more electrons than protons. An object has more protons than electrons. electrically charged negatively charged Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Types of Charges electrically neutral positively charged Electricity and Magnetism 17 Name Date Key Concept Builder Class LESSON 1 Electric Charges and Electric Forces Key Concept How do electrically charged objects interact? Directions: On the line before each item, write I if the substance is an electric insulator or C if the substance is an electric conductor. 1. aluminum 2. paper 3. glass 4. iron 5. plastic 6. gold 7. copper 8. wood 9. rubber Directions: Respond to each statement on the lines provided. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 10. Contrast electric insulators and electric conductors. 11. Will an electric charge spread over an entire balloon? Explain. 18 Electricity and Magnetism Name Date Class Key Concept Builder LESSON 1 Electric Charges and Electric Forces Key Concept How do electrically charged objects interact? Directions: Answer each question in the space provided. Question Answer 1. What is an electric force? 2. What is an electric field? Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3. How will two positively charged objects interact? 4. How will two negatively charged objects interact? 5. How will a negatively charged object and a positively charged object interact? 6. What can you infer about the electric charges of two objects that attract each other? 7. What can you infer about the electric charges of two objects that repel each other? Electricity and Magnetism 19 Name Date Class Lesson Quiz A LESSON 1 Electric Charges and Electric Forces Multiple Choice Directions: On the line before each question or statement, write the letter of the correct answer. 1. A particle that has equal amounts of positive charge and negative charge is A. positively charged. B. electrically neutral. C. negatively charged. 2. Which material is an insulator in which electric charges cannot easily move? A. gold B. plastic C. aluminum 3. Which material is a conductor in which electric charges easily move? A. wood B. paper C. copper Matching Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term is used only once. 24 5. the loss of an unbalanced electric charge A. electric force 6. the push or pull between charged objects B. electric discharge 7. the invisible region around any charged object C. electric field Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 4. How do objects become electrically charged? A. Protons move from one object to another. B. Neutrons move from one object to another. C. Electrons move from one object to another. Name Date Class Lesson Quiz B LESSON 1 Electric Charges and Electric Forces Multiple Choice Directions: On the line before each question or statement, write the letter of the correct answer. 1. A negatively charged particle has A. more protons than electrons. B. more electrons than protons. C. neutrons and protons but no electrons. D. an equal number of protons and electrons. 2. Which material is classified as an insulator? A. iron B. gold C. plastic D. aluminum Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3. Which material is classified as a conductor? A. glass B. paper C. wood D. copper 4. When two objects touch, which object becomes negatively charged? A. the object that has the greater mass B. the object that loses electrons more easily C. the object that has the smaller surface area D. the object that holds electrons more tightly Matching Directions: On the line before each definition, write the letter of the term that matches it correctly. Not all terms are used. 5. the loss of an unbalanced electric charge A. electric force 6. the push or pull between charged objects B. electrically neutral 7. the invisible region around any charged object C. electrically charged D. electric discharge E. electric field Electricity and Magnetism 25 Name Date Class Lesson Outline LESSON 2 Electric Current and Electric Circuits A. Electric Current—Moving Electrons 1. The movement of electrically charged particles in one direction can occur in a(n) . a. Because of their motion, moving electrons contain energy. b. As electrons move from atom to atom, this energy can transform into or energy. 2. Electric current can be either a(n) current or an alternating current. a. An electric current that flows in only one direction is a(n) current. b. An electric current that frequently changes direction is a(n) current. c. Most current used in homes and businesses is Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. current. B. The Circuit—A Path for Electric Current 1. The path through which an electric current flows is called a(n) 2. . circuits are found in flashlights, doorbells, and many appliances. a. Sources of energy can come from , generators, solar cells, and fuel cells. b. chemical reactions within a battery move electrons from the terminal to the 3. A circuit needs a device to terminal. electric energy to other forms of energy. a. Energy transformations occur when current flows through a circuit that has . b. Electric resistance is a measure of how it is for a current to pass through a material. Electricity and Magnetism 29 Name Date Class Lesson Outline continued c. Materials with electric resistance transform more electric energy into other types of energy, such as 4. A circuit also needs an electric . to carry the current to an from the other components of the circuit. a. Most conductors in a circuit are in the form of . b. A good conductor has low electric . 5. Electric circuits can be circuits, in which there is only one path for the current to follow, or contain more than one path for current. circuits, which C. Voltage and Electric Energy 1. The unit used for counting electrons in a circuit is the 2. The . of an electric energy source is the amount of energy used to move a(n) circuit. of electrons through the D. A Practical Electric Circuit 1. An electric circuit could contain a(n) that allows you to start or stop a device. energy. 3. The circuit could also contain an electric transforms electric energy into , which energy. 4. The circuit could contain a temperature-sensitive switch that would automatically turn the device off if it becomes dangerously 30 . Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 2. The circuit could contain a heating device, which transforms electric energy into Name Date Class Content Practice A LESSON 2 Electric Current and Electric Circuits Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term is used only once. 1. the movement of electrically charged particles A. alternating current 2. an electric current that continually flows in one B. direct current direction 3. an electric current that continually reverses direction C. electric circuit D. electric current E. electric resistance 4. a closed path in which an electric current flows F. generator 5. the end of a battery from which electrons flow G. negative terminal 6. the end of a battery into which electrons flow H. positive terminal 7. a machine that transforms mechanical energy to I. voltage electric energy 8. a measure of how difficult it is for an electric current to flow in a material 9. the amount of energy used to move one coulomb Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. of electrons through a circuit 32 Electricity and Magnetism Name Date Class Content Practice B LESSON 2 Electric Current and Electric Circuits Directions: On each line, write the term that correctly completes each sentence. 1. The movement of charged particles is an electric current. 2. Portable devices such as flashlights often use current. 3. A simple circuit needs a source of such as a battery. 4. A simple circuit also needs a conductor such as a(n) . 5. The positively charged end of a battery is called the terminal. 6. The negatively charged end of a battery is called the terminal. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 7. Generators transform energy to energy. 8. Copper and aluminum make good wires in electric circuits because they are excellent 9. A(n) . is the unit used to count electric charges. 10. A high reading means that an electric circuit is transforming large amounts of energy. Electricity and Magnetism 33 Name Date Language Arts Support Class LESSON 2 Writing Activity: Writing a Summary A summary is a short version of a large amount of text. When you write a summary, you use words to explain the main idea and details of a concept in simpler terms. Writing summaries can help you understand complex concepts and communicate them to someone who is not familiar with them. When you read about the concept that you will be summarizing, pay attention to the main idea of the text and the relevant details that you will need to include. Also note unimportant details that you can leave out of your summary. Directions: Reread the section in Lesson 2 of your textbook titled Series and Parallel Circuits. In your own words, write a summary in the space provided. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 34 Electricity and Magnetism Name Date Class Language Arts Support LESSON 2 Writing Activity: Creating a Concept Map A concept map can help you understand the relationship between concepts. A concept map connects terms, or concepts, using descriptions. To make a concept map, write the central concept in the center of the paper. Add concepts to the map, connecting the terms using descriptive phrases and making as many connections as possible. The example below illustrates how to connect terms in a concept map. parallel circuit electric current two types path for Electric Circuit series circuit Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Directions: Make a concept map that includes the terms below. The central concept is written for you. You may include additional terms or concepts in your concept map. alternating current battery conductors direct current electric circuit electrons generator insulators negatively charged Electric Current Electricity and Magnetism 35 Name Date Class Math Skills LESSON 2 Using Fractions Each device in a circuit transforms a portion of the source’s electric energy into other forms of energy such as light and heat. To find the fraction of energy used by a device in the circuit, divide the voltage reading across the device by the total voltage of the energy source. The sum of all the fractions must add up to 1, the total energy in the circuit. A 12-volt (V) battery is connected to two lightbulbs in a series circuit. The voltage reading across the first lightbulb is 3 V. What portion of the battery’s energy transforms in the second lightbulb? Step 1 Find the fraction of energy transformed by the first lightbulb. The lightbulb transformed 3 out of the 12 volts. 3V 3 1 _____ = ___ = __ 4 12 V 12 Step 2 Write an equation. Remember that all the fractions must add up to 1. 1 +x=1 __ 4 Step 3 Solve for the missing number. Any fraction that has the same number in the numerator and denominator equals 1. 3 The second lightbulb transforms __ of the source’s energy. 4 Practice 1. A 12-V battery powers two lightbulbs 3. A 12-V battery powers three lightbulbs in a series circuit. The voltage reading across one lightbulb is 6 V. What portion of the battery’s energy transforms in the other lightbulb? in a series circuit. The voltage reading is 6 V across the first lightbulb and 3 V across the second lightbulb. What portion of the battery’s energy transforms in the third lightbulb? 2. A 9-V battery powers three lightbulbs in a series circuit. The voltage reading across each lightbulb is 3 V. What portion of the battery’s energy transforms in each lightbulb? 36 4. An electric heater has an “on” light and a heating element powered by a 120-V source. The voltage reading across the “on” light is 1 V. What portion of the battery’s energy transforms in the heating element? Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3 1 = __ 4 - __ 1 = __ x = 1 - __ 4 4 4 4 Name Date Key Concept Builder Class LESSON 2 Electric Current and Electric Circuits Key Concept How are electric current and electric charge related? Directions: Respond to each statement on the lines provided. 1. Compare an electric charge and an electric current. 2. Compare the kinds of devices that usually use direct current and alternating current in the United States. 38 Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Directions: Draw how electrons move in a direct current and in an alternating current in the space provided. Use symbols, labels, and arrows to label your drawing. Name Date Class Key Concept Builder LESSON 2 Electric Current and Electric Circuits Key Concept What are the parts of a simple electric circuit? Directions: Answer each question or respond to each statement in the space provided. Question Answer 1. What is an electric circuit? 2. What are the parts of a simple electric circuit? Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3. Give an example of a source of electric energy. 4. Explain how electrons move through a battery. 5. Give an example of a conductor used in an electric circuit. 6. Should a conductor have high or low electric resistance? Explain. 7. Give an example of a device that transforms electric energy in an electric circuit. 8. What determines how much electric energy flowing through a circuit is transformed to other forms of energy? Electricity and Magnetism 39 Name Date Class Key Concept Builder LESSON 2 Electric Current and Electric Circuits Key Concept How do the two types of electric circuits differ? Directions: Write the correct term from the word bank on each line. Terms will be used more than once. battery conductor lightbulb switch 5. 1. 6. 2. 8. 4. – + – + 7. 3. Figure A Figure B Directions: Use the diagram to answer each question on the lines provided. 10. How were you able to distinguish between the two circuits? 11. In the figures above, which parts are sources of energy? 12. Which parts are devices for transforming electric energy into another form of energy? 13. Which parts are the conductors? 40 Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 9. Which figure above shows a series circuit? Which one shows a parallel circuit? Name Date Key Concept Builder Class LESSON 2 Electric Current and Electric Circuits Key Concept How do the two types of electric circuits differ? Directions: On the line before each statement, write T if the statement is true or F if the statement is false. If the statement is false, change the underlined word(s) to make it true. Write your changes on the lines provided. 1. A series circuit is an electric circuit that has multiple paths that an electric current can flow through. 2. All the devices in a series circuit are connected end-to-end. 3. Any break, or opening, in a parallel circuit causes the current to stop flowing through the entire circuit. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 4. Houses use parallel circuits for their electrical needs. 5. A parallel circuit is an electric circuit that has only one path through which an electric current can flow. 6. In a parallel circuit, each device connects to the electric source using a separate path, or branch. 7. If you turn off one light in a parallel circuit, the other lights will remain lit. 8. Unlike series circuits, parallel circuits need sources of energy, conductors, and devices for transforming electric energy to another type of energy. Electricity and Magnetism 41 Name Date Class Lesson Quiz A LESSON 2 Electric Current and Electric Circuits Completion Directions: On each line, write the term from the word bank that correctly completes each sentence. Each term is used only once. electric circuit electric current generator voltage electric resistance 1. The movement of electrically charged particles is 2. A(n) . is a closed, or complete, path in which an electric current flows. 3. A(n) transforms mechanical energy to electric energy. 4. is a measure of how difficult it is for an electric current to flow in a material. 5. The amount of energy used to move one coulomb of electrons through the circuit is its . Multiple Choice Directions: On the line before each statement, write the letter of the correct answer. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 6. An electric current that continually flows in one direction is A. a direct current. B. a parallel current. C. an alternating current. 7. The electric devices in most homes are a part of A. a series circuit. B. a parallel circuit. C. an alternating circuit. 44 Electricity and Magnetism Name Date Class Lesson Quiz B LESSON 2 Electric Current and Electric Circuits Completion Directions: On each line, write the term from the word bank that correctly completes each sentence. Not all terms are used. battery chemical energy electric circuit electric current electric resistance generator terminal voltage 1. The movement of electrically charged particles is 2. A(n) . is a closed, or complete, path in which an electric current flows. 3. A(n) 4. transforms mechanical energy to electric energy. is a measure of how difficult it is for an electric current to flow in a material. 5. The amount of energy used to move one coulomb of electrons through the circuit is its . Short Answer Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Directions: Respond to each statement on the lines provided. 6. Compare and contrast direct current and alternating current. 7. Differentiate parallel circuits and series circuits. Electricity and Magnetism 45 Name Date Class Lesson Outline LESSON 3 Magnetism A. What is a magnet? 1. Any object that attracts iron is a(n) . 2. Iron is an example of a(n) because a magnet attracts iron. B. Magnetic Fields and Magnetic Forces 1. A magnet is surrounded by an invisible . 2. A push or pull that a magnet applies on a magnetic material is a(n) . a. This force exists even if the objects are not . b. Magnetic field lines start on the pole of a magnet and end at the pole. 3. Magnetic poles apply . a. Two poles of the same type each other. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. b. A north pole and a south pole each other. 4. Molten iron and nickel in Earth’s cause Earth to act like a giant magnet. a. Earth has a magnetic north pole and a magnetic . b. Earth’s magnetic south pole is near Earth’s geographic Pole. C. Magnets 1. Atoms are grouped in in some materials. a. A magnetic domain is a region in a magnetic material in which the of the atoms all point in the same direction. b. The individual magnetic fields combine to form magnetic field. 2. In nonmagnetic materials, the random magnetic fields cancel out the magnetic of each other. 3. Some magnetic materials, such as iron and grouped in a. Not all magnetic materials are Electricity and Magnetism are . . 49 Name Date Class Lesson Outline continued b. If the magnetic domains point in the same direction, the material becomes a(n) . 4. Magnetic materials are known as either soft magnetic materials or . a. Soft magnetic materials form magnets. b. Hard magnetic materials form magnets. D. Combining Electricity and Magnetism 1. The relationship between electricity and magnetism is called . 2. Electric current is produced when a(n) and a wire move past each other. 3. An electromagnet is a type of temporary magnet produced when a current-carrying wire is wrapped around a(n) core. 4. The magnetic field of an electromagnet can be turned on and off by turning the on and off. 5. The strength of an electromagnet can be controlled by controlling the amount of Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. in the coil, or by the number of in the coil. 50 Electricity and Magnetism Name Date Content Practice A Class LESSON 3 Magnetism Directions: On the line before each statement, write the letter of the correct answer. 1. An object that attracts iron is A. a magnet. B. a generator. C. an electromagnet. 2. Any object that a magnet attracts is a magnetic A. pole. B. field. C. material. 3. The push or pull that a magnet applies to another magnet or to an object made of a magnetic material is a magnetic A. field. B. force. C. domain. 4. The place on a magnet where the magnet exerts the strongest magnetic force 5. A group of atoms where the magnetic fields of the atoms point in the same direction is A. a magntic force. B. an electromagnet. C. a magnetic domain. 6. A temporary magnet made with a current-carrying wire coil wrapped around a magnetic core is A. a magnetic field. B. an electromagnet. C. a permanent magnet. 52 Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. is the magnetic A. pole. B. force. C. domain. Name Date Content Practice B Class LESSON 3 Magnetism Directions: Explain the relationship that exists between each set of terms on the lines provided. 1. magnet, magnetic material 2. magnetic force, magnetic poles 3. magnetic field, magnetic domain Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 4. nonmagnetic material, magnet 5. soft magnetic material, hard magnetic material 6. temporary magnet, permanent magnet 7. generator, electromagnet Electricity and Magnetism 53 Name Date Key Concept Builder Class LESSON 3 Magnetism Key Concept What causes a magnetic force? Directions: Answer each question on the lines provided. 1. What is a magnetic force? 2. How does distance affect the strength of the magnetic force? 3. What is a magnetic pole? Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 4. What are the two types of magnetic poles? 5. How do magnetic poles interact? Directions: Draw arrows between each set of bar magnets to show whether the magnets will attract one another (→←) or repel one another (←→). S represents the south pole, and N represents the north pole. 6. 7. 8. 9. S N S N S N N S N S N S N S S N Electricity and Magnetism 55 Name Date Class Key Concept Builder LESSON 3 Magnetism Key Concept How are magnets and magnetic domains related? Directions: Use the diagram to answer each question on the lines provided. Figure A Figure B S S N S S S N S N N N S N S N S N S S N S N S N S N S S N S N S N N S N S N S N S S N N S S N N S S N N S N N S N S N S N S S N S N N S S N N N S S N N N N S S N S S S N N S S S N N S S N N N S N N S S S S N N S N N N S S S S N N S S Figure C N N S N N N S S N N S S N S N S S N N S S N N S S N N S S N N S S N N S N N S S N N S S N N S S N N S S N N S S N N S S S N S N N S S N N S S 1. What do the smallest circles represent in each of the three diagrams? 2. Which figure shows a nonmagnetic material? Use the concept of magnetic domains to explain how you reached your answer. explain how you reached your answer. 4. Which figure shows a magnet? Use the concept of magnetic domains to explain how you reached your answer. 56 Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 3. Which figure shows a magnetic material? Use the concept of magnetic domains to Name Date Class Key Concept Builder LESSON 3 Magnetism Key Concept How are magnets and magnetic domains related? Directions: On each line, write the term from the word bank that correctly completes each sentence. Each term is used only once. atoms iron magnetic domains magnetic field magnetic materials magnets nonmagnetic materials plastic All materials are made of (1.) A(n) (2.) (3.) . surrounds each atom. Some atoms are grouped into , which means that the magnetic fields of the groups of atoms are aligned. The atoms of materials such as (4.) are not grouped in magnetic domains. These materials are (5.) . The atoms of materials such as (6.) are grouped into magnetic domains. If Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. the magnetic domains point in random directions, then the materials are (7.) . If the magnetic domains point in the same direction, then the materials are (8.) . Directions: Answer each question on the lines provided. 9. Is a nail a soft magnetic material or a hard magnetic material? Explain. 10. What happens to the magnetic domains of a nail when it is placed near a magnet? Is the nail a magnet? Explain. 11. What happens to the magnetic domains of a nail when it is placed far from a magnet? Is the nail a magnet? Explain. Electricity and Magnetism 57 Name Date Class Key Concept Builder LESSON 3 Magnetism Key Concept How are electric currents and magnetic fields related? Directions: Circle the term in parentheses that correctly completes each sentence. 1. The relationship between electricity and magnetism is called (electric current/electromagnetism). 2. A generator can produce an electric current by passing a wire coil through a magnetic (field/domain). 3. If the wire coil in a generator connects to a(n) (closed/open) circuit, then electric charges move through the circuit as the magnet moves past the wires. 4. If the magnet in the generator (begins/stops) moving, the electric current stops flowing. 5. If a current-carrying wire forms a coil, then the magnetic field around the wire becomes 6. If a (hard/soft) magnetic core is placed within the coil formed by a current-carrying wire, then the magnetic field around the wire becomes stronger. 7. An electromagnet is a (temporary/permanent) magnet made with a current-carrying wire wrapped around a soft magnetic core. 8. The magnetic field of an electromagnet (can/cannot) be turned off and on using the current in the coil. 9. The north and south poles of an electromagnet (reverse/stay the same) if the current reverses. 10. The strength of a(n) (magnet/electromagnet) can be controlled by the number of windings in the coil and the amount of electric current in the coil. 58 Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. (stronger/weaker). Name Date Class Lesson Quiz A LESSON 3 Magnetism Matching Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term is used only once. 1. a group of atoms with magnetic fields pointing in the same direction 2. a push or pull exerted by a magnet A. magnetic force B. magnetic material C. magnetic domain 3. a substance that a magnet attracts True or False Directions: On the line before each statement, write T if the statement is true or F if the statement is false. If the statement is false, change the underlined word(s) to make it true. Write your changes on the lines provided. 4. A current-carrying wire is surrounded by a magnetic field. 5. Iron is a material attracted by magnets. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 6. If two like magnetic poles are next to one another, the magnets attract one another. 7. Nonmagnetic materials have atoms grouped in domains that point in random directions. 8. Temporary magnets are made of hard magnetic materials. Electricity and Magnetism 61 Name Date Class Lesson Quiz B LESSON 3 Magnetism Matching Directions: On the line before each definition, write the letter of the term that matches it correctly. Not all terms are used. 1. a group of atoms that has magnetic fields pointing in the same direction A. electromagnet B. magnetic force 2. a push or pull exerted by a magnet C. magnetic pole 3. a substance that a magnet attracts D. magnet 4. an object that attracts iron E. magnetic material 5. surrounds a current-carrying wire F. magnetic field G. magnetic domain Short Answer Directions: Respond to each statement on the lines provided. 6. Define magnetic pole and explain how magnets interact when their like poles are placed next to one another. 8. Explain how the materials that make up temporary magnets and permanent magnets differ. 62 Electricity and Magnetism Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 7. Describe the arrangement of atoms in a magnetic material. Lesson Outline for Teaching Lesson 1: Electric Charges and Electric Forces A. Electric Charges Lesson Outline continued the objects. 3. The electric force between two charged objects depends on the type of charge on a. Two negative objects push each other away. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. b. Two positive objects push each other away. 1. Each atom contains a core called the nucleus. c. A positive object and a negative object pull each other together. C383_082_087_CRF_AnsOut_892505.i83 83 Electricity and Magnetism 6/22/10 11:27:23 AM T3 As clothes rub against each other, electrons are transferred, and the items become charged. Opposite items attract each other. On cold days there are fewer water molecules in the air to accept charges from the charged items. Why do clothes stick to each other when you take them out of the dryer on a cold, dry day? Discussion Question a. The nucleus is made up of smaller particles called protons and neutrons. 6/22/10 11:27:22 AM b. Atoms also contain electrons which move around the nucleus. c. Protons and electrons have electric charge. a. Protons have positive charge; electrons have negative charge. 2. Electric charges are either positive or negative. b. Atoms are electrically neutral because they have equal amounts of positive and negative charges. electrons. c. Electrically neutral objects become electrically charged when they gain or lose d. An object that loses electrons becomes positively charged. e. An object that gains electrons becomes negatively charged. 3. Electric discharge is the loss of unbalanced electric charge by an object. static cling lasts longer on dry days. a. Some electric discharge occurs slowly, for example, maybe you have noticed that b. A lightning strike is an example of an electric discharge that occurs quickly. 4. Electric charges move at different rates through different materials. a. Materials through which electric charge moves easily are called electric conductors. insulators. b. Materials through which electric charge cannot move easily are called electric c. Examples of insulators include plastic, wood, and glass. d. Some of the best conductors of electric charge are metals. B. Electric Fields and Electric Forces a. Charged objects do not have to touch to exert a force on each other. 1. An electric charge is surrounded by a(n) electric field. apply an electric force. b. Scientists know that there is a(n) invisible region around charged objects that Electricity and Magnetism 2. Electric force is the force an electric field applies to another charged object. C383_082_087_CRF_AnsOut_892505.i82 82 T2 Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Lesson Outline for Teaching Lesson 2: Electric Current and Electric Circuits A. Electric Current—Moving Electrons 1. The movement of electrically charged particles in one direction can occur in a(n) conductor. a. Because of their motion, moving electrons contain kinetic energy. thermal energy. b. As electrons move from atom to atom, this energy can transform into light or a. An electric current that flows in only one direction is a(n) direct current. 2. Electric current can be either a(n) direct current or an alternating current. b. An electric current that frequently changes direction is a(n) alternating current. c. Most current used in homes and businesses is alternating current. B. The Circuit—A Path for Electric Current 1. The path through which an electric current flows is called a(n) electric circuit. a. Sources of energy can come from batteries, generators, solar cells, and fuel cells. 2. Simple circuits are found in flashlights, doorbells, and many kitchen appliances. the negative terminal. b. chemical reactions within a battery move electrons from the positive terminal to 3. A circuit needs a device to transform electric energy to other forms of energy. electric resistance. a. Energy transformations occur when current flows through a circuit that has a material. b. Electric resistance is a measure of how difficult it is for a current to pass through types of energy, such as light. c. Materials with high electric resistance transform more electric energy into other other components of the circuit. 4. An circuit also needs an electric conductor to carry the current to and from the a. Most conductors in a circuit are in the form of wires. b. A good conductor has low electric resistance. Electricity and Magnetism 5. Electric circuits can be series circuits, in which there is only one path for the current to follow, or parallel circuits, which contain more than one path for current. 1. The unit used for counting electrons in a circuit is the coulomb. C. Voltage and Electric Energy T4 6/25/10 7:31:41 PM Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. C383_082_087_CRF_AnsOut_892505.i84 84 Lesson Outline continued coulomb of electrons through the circuit. 2. The voltage of an electric energy source is the amount of energy used to move a D. A Practical Electric Circuit device. 1. An electric circuit could contain a(n) switch that allows you to start or stop a thermal energy. 2. The circuit could contain a heating device, which transforms electric energy into into mechanical energy. 3. The circuit could also contain an electric motor, which transforms electric energy automatically turn the device off if it becomes dangerously hot. 4. The circuit could contain a temperature-sensitive cutoff switch that would Discussion Question What devices in your home use direct current? What devices use alternating current? T5 6/22/10 11:27:25 AM Sample answer: Devices that use direct current include those that use batteries, such as flashlights, cell phones, and hand-held video games. Devices that use alternating current are those that plug into outlets, such as washing machines, televisions, and lamps. Electricity and Magnetism C383_082_087_CRF_AnsOut_892505.i85 85 Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Lesson Outline for Teaching Lesson 3: Magnetism 1. Any object that attracts iron is a(n) magnet. A. What is a magnet? 2. Iron is an example of a(n) magnetic material because a magnet attracts iron. 1. A magnet is surrounded by an invisible magnetic field. B. Magnetic Fields and Magnetic Forces a. This force exists even if the objects are not touching. 2. A push or pull that a magnet applies on a magnetic material is a(n) magnetic force. b. Magnetic field lines start on the north pole of a magnet and end at the south pole. a. Two poles of the same type repel each other. 3. Magnetic poles apply forces. b. A north pole and a south pole attract each other. a. Earth has a magnetic north pole and a magnetic south pole. 4. Molten iron and nickel in Earth’s core cause Earth to act like a giant magnet. b. Earth’s magnetic south pole is near Earth’s geographic North Pole. materials. a. Soft magnetic materials form temporary magnets. b. Hard magnetic materials form permanent magnets. Electricity and Magnetism 4. Magnetic materials are known as either soft magnetic materials or hard magnetic magnet. b. If the magnetic domains point in the same direction, the material becomes a(n) a. Not all magnetic materials are magnets. 3. Some magnetic materials, such as iron and steel are grouped in magnetic domains. effects of each other. 2. In nonmagnetic materials, the random magnetic fields cancel out the magnetic b. The individual magnetic fields combine to form one magnetic field. fields of the atoms all point in the same direction. a. A magnetic domain is a region in a magnetic material in which the magnetic 1. Atoms are grouped in magnetic domains in some materials. C. Magnets T6 6/22/10 11:27:25 AM Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. C383_082_087_CRF_AnsOut_892505.i86 86 Lesson Outline continued 1. The relationship between electricity and magnetism is called electromagnetism. D. Combining Electricity and Magnetism other. 2. Electric current is produced when a(n) magnet and a wire coil move past each wrapped around a(n) magnetic core. 3. An electromagnet is a type of magnet produced when a current-carrying wire is electric current on and off. 4. The magnetic field of an electromagnet can be turned on and off by turning the electric current in the coil, or by the number of loops in the coil. 5. The strength of an electromagnet can be controlled by controlling the amount of Discussion Question How might an electromagnet be helpful in a recycling center? 6/22/10 11:27:26 AM T7 Sample answer: The electromagnet could separate cans containing iron from other recyclable materials. The magnet could move the cans to a separate location; then the cans could be dropped there by stopping the flow of electric current in the electromagnet. Electricity and Magnetism C383_082_087_CRF_AnsOut_892505.i87 87 Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.