LESSON 18: Magnetic Metals ESTIMATED TIME Setup: 5 minutes | Procedure: 5–10 minutes • DESCRIPTION • MATERIALS Use a magnet to determine which types of metal objects are and are not attracted to it. • OBJECTIVE This lesson introduces forces of attraction, specifically magnetism, demonstrating that not all metals are attracted to magnets. Students place metal items on a desk and move a magnet near those metal items. The lesson can be extended to address other properties of metals. • CONTENT TOPICS Scientific inquiry; properties of matter; attractive forces (magnetism); metals Magnet (refrigerator variety will work) or stiff plastic ruler o Clear plastic tape o Assorted metal objects (key, metal paper clip, metal spoon, aluminum foil ball, hair pin, safety pin, penny, nickel, dime, quarter, nail, metal bottle cap, etc.) o o Wood Always remember to use the appropriate safety equipment when conducting your experiment. Refer to the Safety First section in the Resource Guide on pages 391–393 for more detailed information about safety in the classroom. Jump ahead to page 235 to view the Experimental Procedure. NATIONAL SCIENCE EDUCATION STANDARDS SUBJECT MATTER This lesson applies both Dimension 1: Scientific and Engineering Practices and Dimension 2: Crosscutting Concepts from “A Framework for K–12 Science Education,” established as a guide for the updated National Science Education Standards. In addition, this lesson covers the following Disciplinary Core Ideas from that framework: • PS1.A: Structure and Properties of Matter • ETS2.A: Interdependence of Science, Engineering, and Technology (see Analysis & Conclusion) • ETS2.B: Influence of Engineering, Technology, and Science on Society and the Natural World (see Analysis & Conclusion) OBSERVATION & RESEARCH BACKGROUND Scientists often classify elements as either metals or nonmetals. Metals are primarily found on the left side of the periodic table. They are usually solid at a normal room temperature of about 75 °F and have a shiny appearance. Other usual properties of metals include good thermal and electrical conductivity and the ability to be reshaped or hammered thin (known as malleability and ductility, respectively). Nonmetals are usually found on the right side of the periodic table and are generally gases or solids at a normal room temperature. Semi-metals (metalloids) are located between metals and nonmetals on the periodic table and have some properties of both. Magnetism is a unique property of some metal elements but not all. Magnetism is a force of attraction or repulsion between materials that acts at a distance through a magnetic field (region of magnetic force). Some magnets have a stronger magnetic force than others. Force measures the amount of push or pull on an object. Many other forces exist on the earth, such as gravity and intramolecular forces (chemical bonds). A magnet is an object that creates a strong magnetic field. Only certain metals produce a magnetic field. These metals include iron, nickel, and cobalt. All magnets are made of these metals, called ferromagnetic metals. You Be TheLESSON Chemist®Activity Activity Guide Guides | page 232 1: Goofy Putty 232 LESSON 18: Magnetic Metals The ends of a magnet are called its poles, where the magnetic forces are the strongest. All magnets have two poles, a north pole (N) and a south pole (S). Magnets will be attracted by their opposite poles and repelled by like poles. For example, the north pole of one magnet will attract the south pole of another magnet, but the north poles of two magnets will repel each other (as will the two south poles). Therefore, metals with magnetic properties will be attracted to a magnet. Specifically, the north pole of a magnetic metal will be attracted to the south pole of a magnet and vice versa. In this experiment, students explore magnetism by using magnets to test which metals produce a magnetic field. Metal objects that produce a magnetic field will be attracted to the magnet, while metals that do not produce a magnetic field will not be attracted to the magnet. For example, paper clips generally contain iron, and therefore will be attracted to a magnet. On the other hand, U.S. pennies are made primarily of zinc with a copper coating, and therefore will not be attracted to the magnet. FORMULAS & EQUATIONS Iron is one of the most abundant metals on the earth, forming about 5.6% of the earth’s crust. CONNECT TO THE YOU BE THE CHEMIST CHALLENGE For additional background information, please review CEF’s Challenge study materials online at http://www.chemed.org/ybtc/challenge/study.aspx. • Additional information on metals, nonmetals, and semi-metals can be found in the Periodic Table section of CEF’s Passport to Science Exploration: The Core of Chemistry. • Additional information on forces, such as magnetism, can be found in the Forces of Attraction section of CEF’s Passport to Science Exploration: Chemistry Connections. HYPOTHESIS uSome metal objects produce a magnetic field and will be attracted to magnets, while others will not. The chemical symbol for iron is Fe. Its atomic number is 26, and its atomic weight is approximately 55.8 atomic mass units (amu). Iron is alloyed with carbon to create steel. Most metal paper clips are made of steel. Cobalt is an essential part of vitamin B12. The chemical symbol for cobalt is Co. Its atomic number is 27, and its atomic weight is approximately 58.9 amu. Fun Fact A naturally magnetic mineral commonly called lodestone was used in the past to make magnetic compass needles. The word “lode” means “lead” because the compasses were used to lead sailors home. Nickel is a silvery white metal with a high polish. The chemical symbol for nickel is Ni. Its atomic number is 28, and its atomic weight is approximately 58.7 amu. You Be The Chemist® Activity Guide | page 233 LESSON 18: Magnetic Metals DIFFERENTIATION IN THE CLASSROOM LOWER GRADE LEVELS/BEGINNERS Conduct the experiment as described on page 235, but focus the lesson on classifying matter. Discuss physical properties and the different uses of different substances. Physical properties can be observed by using our senses and taking measurements. Some examples of physical properties are color, shape, boiling point, melting point, and density. Have students practice classifying matter based on physical properties. Point out different objects in the room, and ask the students to describe their physical properties and group substances with similar properties together. Ask them to compare and contrast the physical properties of the assorted materials used in the lesson. HIGHER GRADE LEVELS/ADVANCED STUDENTS DESCRIPTION Use a magnet to determine which metal objects are and are not attracted to it. OBJECTIVE This lesson introduces properties of metals and forces of attraction, specifically magnetism, and demonstrates that not all metals are attracted to magnets. OBSERVATION & RESEARCH Scientists often classify elements as either metals or nonmetals. Metals are primarily found on the left side of the periodic table. They are usually solid at a normal room temperature of about 75 °F and have a shiny appearance. Other usual properties of metals include good thermal and electrical conductivity, malleability, and ductility. Electrical conductivity is a measure of the ease with which electricity can travel through a material. Thermal conductivity is a measure of the ease with which thermal energy can travel through a material. Malleability is the ability of a metal to be flattened, shaped, or formed, without breaking, when pressure is applied. Ductility is the ability of a metal to be stretched into a thin wire or thread without breaking. Additionally, luster is the ability of a metal to reflect light, which gives metals their shiny appearance. Magnetism is a unique property of some metal elements, but not all. Magnetism is a force of attraction or repulsion between materials that acts at a distance through a magnetic field (region of magnetic force). Some magnets have a stronger magnetic force than others. Force measures the amount of push or pull on an object. Many other forces exist on the earth, such as gravity and intramolecular forces (chemical bonds). A magnet is an object that creates a strong magnetic field. Only certain metals produce a magnetic field. These metals include iron, nickel, and cobalt. All magnets are made of these metals, called ferromagnetic metals. There are two basic kinds of magnets—permanent and temporary. A permanent magnet keeps a certain level of magnetism for a long time. A temporary magnet acts like a permanent magnet when it is within a strong magnetic field but loses its magnetism when the magnetic field is removed. Any object that is lifted or moved by a magnet acts as a temporary magnet, but generally it loses its magnetism when the permanent magnet is removed. However, in some cases the magnetized object will retain weak magnetic properties. The ends of a magnet are called its poles, where the magnetic forces are the strongest. All magnets have two poles, a north pole (N) and a south pole (S). CONNECT TO THE YOU BE THE CHEMIST CHALLENGE For additional background information, please review CEF’s Challenge study materials online at http://www.chemed.org/ybtc/challenge/study.aspx. • Additional information on metals, nonmetals, and semi-metals can be found in the Atomic Structure and Periodic Table sections of CEF’s Passport to Science Exploration: The Core of Chemistry. • Additional information on forces, such as magnetism, can be found in the Forces of Attraction section of CEF’s Passport to Science Exploration: Chemistry Connections. • Additional information on metallic properties can be found in the Forces of Attraction section of CEF’s Passport to Science Exploration: Chemistry Connections. You Be The Chemist® Activity Guide | page 234 LESSON 18: Magnetic Metals DIFFERENTIATION IN THE CLASSROOM Magnets will be attracted by their opposite poles and repelled by like poles. For example, the north pole of one magnet will attract the south pole of another magnet, but the north poles of two magnets will repel each other (as will the two south poles). Therefore, metals with magnetic properties will be attracted to a magnet. (Specifically, the north end of a magnetic metal will be attracted to the south pole of a magnet and vice versa.) In this experiment, students explore magnetism by using permanent magnets to test which metals produce a magnetic field. Metal objects that produce a magnetic field will be attracted to the magnet, while metals that do not produce a magnetic field will not be attracted to the magnet. For example, paper clips generally contain iron, and therefore will be attracted to a magnet. On the other hand, U.S. pennies are made primarily of zinc with a copper coating, and therefore will not be attracted to the magnet. EXPERIMENTATION As the students perform the experiment, challenge them to identify the independent, dependent, and controlled variables, as well as whether there is a control setup for the experiment. (Hint: If the type of metal object is changed, will it react differently to the magnet.) Review the information in the Scientific Inquiry section on pages 14–16 to discuss variables. NOTES EXPERIMENTAL PROCEDURE 1. Use tape to attach a magnet to the end of the ruler so that the magnet is facing away from the ruler. Do not cover the magnetic surface with the tape. (You do not need to remove the magnet from its decorative casing.) 2. Place your metal objects in a row, and predict which metals will be attracted to the magnet and which will not. 3. Hold the magnet over each item, and record which items are attracted to the magnet. Go back over the objects that were not affected by the magnet one more time just in case you missed any. DATA COLLECTION Have students record data in their science notebooks or on the following activity sheet. Which objects were attracted to the magnet? Which objects were not attracted to the magnet? You can use the table in the activity sheet (or a similar one of your own) for students to record their data. You Be The Chemist® Activity Guide | page 235 LESSON 18: Magnetic Metals ANALYSIS & CONCLUSION Use the questions from the activity sheet or your own questions to discuss the experimental data. Ask students to determine whether they should accept or reject their hypotheses. Review the information in the Scientific Inquiry section on pages 14–16 to discuss valid and invalid hypotheses. ASSESSMENT/GOALS Upon completion of this lesson, students should be able to … • Apply a scientific inquiry process and perform an experiment. • Identify general properties of metals. • Explain magnetism and identify magnetic elements. • Describe forces of attraction and repulsion and how they relate to magnetic poles. • Compare and contrast permanent and temporary magnets (see Differentiation in the Classroom). REAL-WORLD APPLICATIONS • Metal paper clips are generally made from steel wire. Steel is an alloy of iron and carbon. The iron in the paper clips causes them to be attracted to the magnet. • The mineral magnetite, also known as lodestone, is a natural magnet. Small iron particles are often found clinging to the surface of the magnetite stones. Even though it is a relatively weak magnet, it can attract large steel nails. • Magnets and magnetic technology have been widely used in the mining industry. Powerful magnets are used to separate valuable materials from within the mine. They are also used to remove contaminants from the mined materials, such as coal. COMMUNICATION Discuss the results as a class and review the activity sheet. Review the information in the Scientific Inquiry section on pages 14–16 to discuss the importance of communication to scientific progress. MODIFICATIONS/EXTENSIONS Modifications and extensions provide alternative methods for performing the lesson or similar lessons. They also introduce ways to expand on the content topics presented and think beyond those topics. Use the following examples or have a discussion to generate other ideas as a class. • Take the experiment one step further. Use one of the objects that was attracted to the magnet, and place it on the magnet for about a minute. Next, remove the object from the magnet, and see if it can attract your other magnetic objects. Metals that are magnetic can be made into temporary magnets themselves! K-4 See Lesson 2: Steamy Metals for a unit on metals or classifying matter. You Be The Chemist® Activity Guide | page 236 LESSON 18 ACTIVITY SHEET: Magnetic Metals OBSERVE & RESEARCH 1. Write down the materials you see. ____________________________________________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 2. How might these materials be used? __________________________________________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 3. Define the following key terms. Then, provide an example of each by writing the example or drawing/pasting an image of the example. Term Definition Example (write or add image) Metals Nonmetals Semi-metals Magnetism Force Poles 4. Consider whether different metal objects are or are not attracted to magnets and why. uWrite your hypothesis. ______________________________________________________________ ______________________________________________________________________________________ ______________________________________________________________________________________ You Be The Chemist®Activity ActivityGuides Guide | page 237 LESSON 18 ACTIVITY SHEET: Magnetic Metals PERFORM YOUR EXPERIMENT 1. Use tape to attach a magnet to the end of the ruler. Do not cover the magnetic surface with tape. The magnet should face away from the ruler. You do not need to remove the magnet from its cover. 2. Place your metal objects in a row. Predict which metals will be attracted to the magnet and which will not. 3. Hold the magnet over each item. Record which items are attracted to the magnet. Go back over the objects that were not affected by the magnet one more time just in case you missed any. ANALYZE & CONCLUDE 1. In the table below, list all of the objects you will test. Then, record your predictions. (Which objects do you think are magnetic and which are not?) In the last column, record the results. (Which objects were attracted to the magnet?) Object Prediction You Be The Chemist® Activity Guide | page 238 Results LESSON 18 ACTIVITY SHEET: Magnetic Metals 2. Describe the metal objects. How are they similar? How are they different? __________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 3. Do similar poles of two magnets attract or repel each other? ____________________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 4. What happens when you move the magnet over the metal objects? ________________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 5. Magnets have two poles. What are they called? ________________________________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 6. Is your hypothesis valid? Why or why not? If not, what would be your next steps? __________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ You Be The Chemist®Activity ActivityGuides Guide | page 239 LESSON 18 ACTIVITY SHEET: Magnetic Metals EXPAND YOUR KNOWLEDGE—ADVANCED 1. Define the following key terms. Then, provide an example of each by writing the example or drawing/pasting an image of the example. Term Definition Example (write or add image) Electrical conductivity Thermal conductivity Malleability Ductility Luster Permanent magnet Temporary magnet 2. What happens when you place a magnetic metal on the magnet for a minute and then move it over other metal objects? Why? ________________________________________________________________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ You Be The Chemist® Activity Guide | page 240 LESSON 18 ACTIVITY SHEET: Magnetic Metals ANSWER KEY Below are suggested answers. Other answers may also be acceptable. OBSERVE & RESEARCH Magnet, ruler, tape, keys, paper clips, coins … 1. Write down the materials you see. ____________________________________________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ Magnets may be used to attract different metals. A ruler may be used to measure. Tape may 2. How might these materials be used? __________________________________________________________________ be used to hold something in place. Keys may be used to open doors. Paper clips may be used to hold paper together. Coins may be used as ______________________________________________________________________________________________________ money. The magnet may be used to test the magnetic properties of different metal objects. ______________________________________________________________________________________________________ 3. Define the following key terms. Then, provide an example of each by writing the example or drawing/pasting an image of the example. Term Definition Metals A set of elements that are usually solid at a normal room temperature and are found primarily on the left side of the periodic table. Nonmetals A set of elements that are generally gases or solids at a normal room temperature and are found primarily on the right side of the periodic table. Semi-metals A set of elements that have some properties of both metals and nonmetals and are found along a zigzag dividing line between metals and nonmetals on the periodic table; also known as metalloids. Magnetism A force of attraction or repulsion between materials that produce a magnetic field. Force A push or pull acting on an object, sometimes causing a change in position or motion. Poles The ends of a magnet, each having an opposite charge, one positive and one negative; these poles are called the north pole and the south pole. Example (write or add image) 4. Consider whether different metal objects are or are not attracted to magnets and why. Some metals objects have magnetic properties (produce a magnetic field) and will be uWrite your hypothesis. ______________________________________________________________ attracted to magnets. Other metals do not have magnetic properties, so they are not attracted to magnets. ______________________________________________________________________________________ ______________________________________________________________________________________ You Be The Chemist® Activity Guide | page 241 LESSON 18 ACTIVITY SHEET: Magnetic Metals ANSWER KEY Below are suggested answers. Other answers may also be acceptable. PERFORM YOUR EXPERIMENT 1. Use tape to attach a magnet to the end of the ruler. Do not cover the magnetic surface with tape. The magnet should face away from the ruler. You do not need to remove the magnet from its cover. 2. Place your metal objects in a row. Predict which metals will be attracted to the magnet and which will not. 3. Hold the magnet over each item. Record which items are attracted to the magnet. Go back over the objects that were not affected by the magnet one more time just in case you missed any. ANALYZE & CONCLUDE 1. In the table below, list all of the objects you will test. Then, record your predictions. (Which objects do you think are magnetic and which are not?) In the last column, record the results. (Which objects were attracted to the magnet?) Object Prediction Results Answers will vary Answers will vary Answers will vary You Be The Chemist® Activity Guide | page 242 LESSON 18 ACTIVITY SHEET: Magnetic Metals ANSWER KEY Below are suggested answers. Other answers may also be acceptable. 2. Describe the metal objects. How are they similar? How are they different? Most of the metal objects are sturdy and hard. __________________________________ Many are a grayish silver color, while others are reddish orange or yellow. Most of the metals are shiny. ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 3. Do similar poles of two magnets attract or repel each other? Similar poles of two magnets repel each other. Opposite poles ____________________________________________ attract each other. ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 4. What happens when you move the magnet over the metal objects? Certain metals are attracted to the magnet. They will rise ________________________________________ and attach to the magnet. ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 5. Magnets have two poles. What are they called? The two poles are called the north pole (N) and the south pole (S). ________________________________________________________ ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ 6. Is your hypothesis valid? Why or why not? If not, what would be your next steps? __________________________ Answer 1: Valid because the data support my hypothesis. ______________________________________________________________________________________________________ Answer 2: Invalid because the data do not support my hypothesis. I would reject my hypothesis and could form a new one, such as … ______________________________________________________________________________________________________ You Be The Chemist® Activity Guide | page 243 LESSON 18 ACTIVITY SHEET: Magnetic Metals ANSWER KEY Below are suggested answers. Other answers may also be acceptable. EXPAND YOUR KNOWLEDGE—ADVANCED Have students complete this section if you used the advanced differentiation information, or challenge them to find the answers to these questions at home and discuss how these terms relate to the experiment in class the next day. 1. Define the following key terms. Then, provide an example of each by writing the example or drawing/pasting an image of the example. Term Definition Electrical conductivity A measure of the ease with which electricity can travel through a material. Thermal conductivity The measure of the rate at which thermal energy can travel through a material. Malleability The ability of a metal to be flattened, shaped, or formed without breaking when pressure is applied. Ductility The ability of a metal to be stretched into a thin wire or thread without breaking. Luster The ability of a metal to reflect light; this property gives metals a shiny appearance. Permanent magnet A type of magnetic substance that keeps a certain level of magnetism for a long time. Temporary magnet A type of magnet that acts like a permanent magnet when it is within a strong magnetic field but loses its magnetism when the magnetic field is removed. Example (write or add image) 2. What happens when you place a magnetic metal on the magnet for a minute and then move it over other metal If you place a magnetic metal on a magnet, it will act as a temporary magnet for a short time until the magnetic field is objects? Why? ________________________________________________________________________________________ removed. It will be attracted to other magnetic objects while it is a temporary magnet. ______________________________________________________________________________________________________ ______________________________________________________________________________________________________ You Be The Chemist® Activity Guide | page 244