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Exploring Magnets and Magnetism Instructor Idea Guide Developed for Queen of Apostles kindergarten program 20 December 1999 Contents: Executive summary......................................................................................................................... 3 Cautions & precautions ................................................................................................................... 4 Kit contents ..................................................................................................................................... 5 Background reading ........................................................................................................................ 6 Preface ......................................................................................................................................... 6 Basics & History.......................................................................................................................... 6 Magnetic Field ............................................................................................................................. 6 Care of permanent magnets ......................................................................................................... 8 Different types of magnets .......................................................................................................... 8 Applications for magnets ............................................................................................................. 8 Electromagnetism ........................................................................................................................ 8 Earth’s magnetic field .................................................................................................................. 9 Biology ...................................................................................................................................... 11 Activities ....................................................................................................................................... 12 Activity: Exploring magnets ...................................................................................................... 13 Activity: Vocabulary Building .................................................................................................. 14 Activity: Magnetic spring .......................................................................................................... 15 Activity: Magnetic fishing game ............................................................................................... 16 Activity: Paperclip pickup ......................................................................................................... 21 Activity: Identify household and workplace uses of magnets ................................................... 23 Activity: Using compasses to detect a nearby magnet .............................................................. 24 Activity: What items do magnets attract?.................................................................................. 25 Activity: Make a magnet ........................................................................................................... 27 Activity: Move a object without touching it .............................................................................. 28 Activity: Make a paperclip float in air....................................................................................... 29 Activity: Make your own refrigerator magnets ......................................................................... 30 Activity: See a magnetic field ................................................................................................... 31 References ..................................................................................................................................... 32 Exploring Magnets and Magnetism 20 Dec 1999 2 Executive summary This document was generated to accompany a kit of magnets and related materials for use in exploring the fundamentals of magnetism for students at a kindergarten level. Some activities may extend beyond this level – instructors should mix, match, and alter activities to suit their needs and curriculum. Background information is provided at a much higher level for the instructor. The kit was assembled and this document was written and edited by Michael Skroch for Mrs. Ferguson’s class in the 1999/2000 school year. This document was complied from various sources and the editor’s personal experience. See the references section at the end of this document for these sources. This document should be available on the Internet at http://www.type-thing.com/qofa/ in various formats. Exploring Magnets and Magnetism 20 Dec 1999 3 Cautions & precautions 1. Some magnets may be small and could be swallowed. 2. Proximity to magnets may damage some items. Keep them at a distance to avoid damage such as: Data on computer magnetic storage devices such as floppy disks or internal hard drives may be erased. Audio and videocassettes may be erased or recordings damaged. Computer monitors or television screens may become magnetized resulting in a distorted picture or distorted colors. Bring a magnet near a television picture; it’s fun! Magnets can damage some delicate watches and compasses. 3. Magnets can be damaged. Dropping magnets or sharply hitting them together cause them to become weaker. Making magnets very hot can cause them to become weaker. Exploring Magnets and Magnetism 20 Dec 1999 4 Kit contents The following materials were included in the original kit. Quantity Description 1 This document, Exploring Magnets & Magnetism 1 Blue magnetic wand 4 Red plastic-encased donut magnet 4 Blue plastic-encased donut magnet 4 Yellow plastic-encased donut magnet 1 Red square plastic-encased magnet 1 Green painted square magnet with hole 1 Blue painted round magnet 1 Red painted small rectangular magnet 1 Yellow painted small rectangular magnet 1 Purple painted rectangular magnet with hole 1 Orange painted circular magnet with hole 1 Cabinet latch magnet with hole 3 Plastic rectangular magnets with hole 3 Large round ceramic magnets with hole 1 “Mysterious Magnetic Tube” – iron filing tube with cow magnet in its own case 1 Magnetic wheel action toy – to show toy based upon magnetism 12 Assorted color magnetic sheets “refrigerator magnet” material. 10 Mini compasses 1 Wood stand with wood dowel – for magnetic spring experiment 1 Green string 1 Spool of thread 3 boxes Paper clips 1 Box to contain all supplies 1 Plastic sorting box for small supplies The instructor may wish to supplement this material or ask students to bring in items for certain activities. See suggested activities for details. Exploring Magnets and Magnetism 20 Dec 1999 5 Background reading Preface The following material is provided for the instructor as background reading. As much as appropriate may be used in developing lesson plans. Most material in this section is intended to go well beyond the kindergarten and lower primary education level. Skip any material that is not of use or of interest. Basics & History Magnetism is an invisible field that can exert both attractive and repulsive forces on certain objects. Although we cannot see a magnetic field, we can look at magnets and objects they interact with in order to better understand magnetism. A magnetic field exists around and is generated by magnets. Long ago certain rocks were found to attract iron. These rocks were the first magnets. Magnetism has been known about for centuries. Chinese and Greek mythology contain references to this "magical" property. According to the Encyclopedia Britanicia, the mineral magnetite - a magnetic oxide of iron - appears in Greek writings from as early as 800 B.C. This mineral, which even in the natural state has a strong attraction for iron, was mined in the Greek province of Magnesia, in Thessaly. Pliny the Elder, however, ascribes the name to its discover, the shepherd Magnes, "the nails of whose shoes and the tip of whose staff stuck fast in a magnetic field while he pastured his flocks." Magnetic Field A bar magnet is a seemingly ordinary piece of metal from which invisible magnetic field lines originate (an imaginary concept used to explain the phenomenon we observe in magnetism). These magnetic field lines effect any magnetic material in the vicinity of the magnet. Magnets have a north pole where by convention, magnetic lines of force point outward and a south pole where they point inward. Opposite poles attract each other; while similar poles repel each other. A toy bar magnet has a magnetic field (about 1000 Oersted) thousands of times larger than the Earth's surface magnetic field (about 1/4 Oersted) and about the strength of the field found in sunspots on the solar surface. “Oersted” are units of magnetic field strength. Magnetic theory states that all lines of force exiting one pole must return to the other pole. Since these lines of force tend to stay near the magnet, it makes sense that the magnetic field is weaker the father you move away from the magnet. Magnetic fields are able to penetrate most nonmagnetic materials. They easily pass through air, wood, glass, or your hand without affecting these materials. Therefore you will be able to demonstrate to students that a magnet can move a Exploring Magnets and Magnetism 20 Dec 1999 6 piece of metal through a wooden table, sheet of paper, or your hand. The mysterious properties of an invisible force that penetrates solid objects with ease is fascinating even to those who understand magnetism. To a child, it seems like magic. One can view what appear to be lines of force by using iron filings on a sheet of paper with a magnet below. The filings will tend to line up in a distinct pattern as the magnetic field magnetizes the minute particles. All magnetic fields are the result of moving electric charges (see Electromagnetism section below). In the case of solid materials such as bar magnets, the moving charges are the individual electrons rotating about the atomic nuclei. Therefore each atom acts like a very small magnet. In materials where the atoms are oriented in random directions, their individual magnetic fields cancel out. In permanent magnets, most of the atoms are lined up so their magnetic fields add together. In this case we can observe a north and south pole at the ends of the magnet. At center of a magnet little magnetic field can be observed because the magnetic field of every atom’s north pole feeds directly into that of a nearby south pole. This analogy can be demonstrated with bar or disk Exploring Magnets and Magnetism 20 Dec 1999 7 magnets in place of atoms – if you allow same-sized magnets to attach themselves to one another to form one unit, you’ve created a stronger magnet at the unit’s north and south poles. You will not easily observe any magnetic field where the two magnets have attached themselves together. Materials differ in the ease with which their atoms can be lined up. In non-magnetic materials, the atoms don't turn around and line up very easily. The magnetic field surrounding a strong magnet can temporarily magnetize objects made of iron, steel, nickel, or cobalt. When an iron nail is brought near the north pole of a magnet, the south poles of the atoms are pulled around to line up facing the north poles. The particles of a nail are lined up in one direction and the whole nail becomes a temporary magnet. But if the nail is taken away from the magnet, the particles revert back to their random distribution and the nail's magnetism disappears. Repeatedly stroking the nail with a strong magnet may impart a longer-lasting effect on the nail so that it retains some magnetic field. Care of permanent magnets Warn students that magnets will break or lose their magnetism if dropped, hit together, or heated. Such actions cause the internal particles to rearrange themselves, decreasing the effectiveness of the magnet. To store a U-shaped magnet (or horseshoe magnet) so that it retains its magnetic properties, place a piece of soft iron called a keeper, across the ends. Bar magnets and other shapes of magnets do not require such care. Different types of magnets Not all permanent magnets are created in the same way and it is not always obvious from physical construction where the north and south poles are located on the magnet. Applications for magnets The first application of magnetism was the compass. Some writers believe the compass was in use in China as early as the 26th century B.C. Others believe that it was introduced to China in the 13th century A.D. and its invention was of Italian or Arab origin. Magnets hold refrigerator doors closed and sealed. Magnets often hold cabinets closed. Office buildings use magnetic locks on doors to keep them closed without a physical lock – the magnet can be easily turned on and off to allow or block access based upon a keypad or badge reader. Mag-lev trains float on a cushion of magnetic fields and can travel at hundreds of miles per hour. Cow magnets are cylindrical bar magnets with rounded edges. They were designed to be put down a cow’s throat (swallowed) to collect bits and pieces of metal that the cows might swallow while grazing. The magnet and collected debris passes through the cows system. A suggested activity in this document covers household use of magnets. Electromagnetism The most useful properties of magnetism are connected with the relationship between magnetism and moving charge (electricity or electric current) as discussed earlier. Understanding of this Exploring Magnets and Magnetism 20 Dec 1999 8 relationship is the foundation of the field of Electrical Engineering and has resulted in all of our modern-day electronics and radio (AM, FM, cell phone, satellite) communications. This discussion is obviously beyond the Kindergarten level, but is included should the instructor desire more detail. Every time electricity flows, a magnetic field is also created. The flow of electricity between the batteries in your flashlight and the bulb that glows creates a static magnetic field around the path of that electricity (wires, batteries, bulb filament). In this case, the magnetic field is static or non-changing, just like a bar magnet. When the electricity is not steady (Alternating Currnet (AC), not Direct Current (DC)) such as if you turn the flashlight on and off, or use an AC power source like the electricity in your home wiring, the magnetic field and electric field (voltage) continually change strength. Earth’s magnetic field The Earth on which we live has a relatively static magnetic field that is similar to that created by a bar magnet. Current scientific belief is that the magnetic field is generated by immense flow of electric current circulating near the core of our planet. The circulation has to do with flow of molten material near the core. The Earth’s magnetic field extends far out into space and protects us from charged particles flowing outward from the sun and those traveling randomly through space. The point where Earth’s magnetic field stops and runs into the Sun’s magnetic field is called the “magnetopause” (bow shock). The shape of the magnetic field around the earth is called the “magnetosphere.” It has been mapped by satellites and probes sent out by NASA and other organizations. The solar wind flows around the Earth's magnetic field but distorts the field as it does so. The solar wind compresses the Earth's magnetic field on the day side and stretches it out into a long anti-sunward tail on the night side. The location of the magnetic pole is not fixed. It changes slowly with time. The magnetic pole in the geographic north is called the Earth's North Magnetic Pole by convention. The North magnetic Pole is actually the south pole of the Earth's magnetic field. This came about because Exploring Magnets and Magnetism 20 Dec 1999 9 the north pole of a compass was defined as the pole that points to the geomagnetic north. However, since opposite poles attract, the north pole of the magnetic needle in the compass must point toward the south pole of the Earth's magnetic field. The Earth's surface magnetic field has strength and a direction. The sites of the magnetic poles are the locations where the magnetic field lines are completely vertical. Maps with the locations of the magnetic poles are given above. At these locations, harmful radiation from the sun more easily penetrates to the Earth's middle and lower atmospheric layers. Dangerous particles are not able to penetrate to the Earth's surface but are forced by the magnetic field to move around the Earth. Particles gain entry through the cusps that are shaped like funnels over the polar regions or they gain entry far downstream from the Earth. The particles that enter downstream travel toward the Earth and are accelerated into the high-latitude ionosphere and produce the aurora borealis (northern lights) and aurora austrialis (southern lights). Other higher energy particle radiation that could pose a danger to life here on Earth, is forced to drift around the Earth within two large donut-shaped regions called the radiation belts. Invisible magnetic fields are the reason that particle radiation moves in this way. The poles of Earth’s magnetic field are not exactly lined up with the orbital poles of the Earth. Both the north and south magnetic poles are about 1200 miles from the orbital poles. Therefore magnetic compass directions must be corrected for depending where on the Earth you are located. The magnetic field of the earth is not exactly constant either, but it doesn’t move so much one has to worry about it. Over the history of humans recording its location, the north magnetic pole on Earth has migrated several degrees. Also, records of magnetic alignment of rock at the boundaries of new tectonic plate activity (for instance, the center of the Atlantic ocean where molten rock forces its way out) show that Earth’s magnetic field abruptly switches polarity about every hundred thousand to many millions of years. The north and south magnetic poles swap each of these times. Physicists and mathematicians discovered that an alternating electric or magnetic fields like this can create “electromagnetic waves” which can exist without wires or batteries. The speed at which the electromagnetic wave reverses polarity (similar to turning a switch on and off) is known as its frequency. Electromagnetic waves can exist in space because as the magnetic field collapses, it generates an electric field. As the electric field collapses, it generates a magnetic field. This process continues as the electromagnetic wave propagates through space. Very low frequencies are known as radio waves, the type that allows us to listen to broadcast radio, television, and cell phone communications. Most of these operate at frequencies that change far faster than you could turn a switch on and off. Higher frequencies generate radar (to track airplanes) and signals that communicate with satellites far above the earth. One band of frequencies near radar is known as “microwaves.” These are able to easily vibrate molecules of water and in the process heat them up – which is how our microwave ovens operate. X-rays are even higher forms of electromagnetic waves. Even higher frequencies of electromagnetic waves make up the light we see, different frequencies making different colors. Frequencies that are higher still often come from outer space in the form of “gamma rays,” most of which are stopped by our atmosphere before the reach the ground. All of these frequencies of electromagnetic waves from the lowest to highest is known as the “electromagnetic spectrum.” Exploring Magnets and Magnetism 20 Dec 1999 10 Biology Humans were not the first living creatures to take advantage of magnetism. Scientists have shown that migratory and other birds are able to sense the magnetic field of the earth (see electromagnetism) and use it to navigate. It is currently believed that they have a sensory organ in their brains that can detect this field. Some bacteria have been shown to be able to detect a magnetic field. One can observe tiny magnetic particles within these microorganisms, which tend to align them to the local magnetic field. It is not generally known what benefit these bacteria gain from harboring magnets within their bodies. The human body may rely on electromagnetic fields to organize cell growth and organization, help in the repair of damaged bones and other tissues. Studies in these areas are fairly new. Exploring Magnets and Magnetism 20 Dec 1999 11 Activities The following activities are suggestions and ideas for the instructor. Please select activities of interest combine them, and alter them to fit instructional need. Exploring Magnets and Magnetism 20 Dec 1999 12 Activity: Exploring magnets Objectives: Allow students to have self-exploration of magnets and objects. Materials: Various magnets, magnets connected to a short sturdy string, metal object connected to a short sturdy string, a selection of magnetic and non-magnetic objects (metal, paper, wood, plastic, and other objects around the classroom.) Preparation: 1. Place objects on table. Activity: 2. Inform students to explore how magnets work themselves. Explain the things that should not be done with magnets (throwing, putting in mouth, spinning on the string, etc.) 3. Ask students to explain how magnets work. 4. Ask about how some parts of magnets push against each other while other parts stick together. 5. Allow them to play with paperclips and see how they interact with magnets. Exploring Magnets and Magnetism 20 Dec 1999 13 Activity: Vocabulary Building Objective: Increase vocabulary related to magnets. Preparation: Perform a set of other activities involving magnets. Materials: None. Activity: The instructor may wish to emphasize the following words during the course of the students involvement with magnets: Repel Attract Force Magnetic Pole Magnetize Magnetic Non-magnetic Compass Exploring Magnets and Magnetism 20 Dec 1999 14 Activity: Magnetic spring Objectives: Motivation, showing repulsive force of magnets, magnetic levitation Materials: 12 red/blue/yellow plastic-encased torroidal magnets from kit, wooden dowel and stand from kit. Preparation: 1. It may be useful to have explained magnets and how different poles attract and similar poles repel each other. It may also be useful to have allowed students to explore how magnets work through self-discovery so they can feel the force of attraction and repulsion. 2. Collect materials. Activity: 3. Place the wooden dowel and stand so that students can see it. Place one torroidal magnet over the dowel so that it sets on the wooden base. 4. Ask the students what they think will happen when you place another magnet on the dowel. Test another magnet to make sure it will attract the first magnet when it is put on the dowel, Allow the two magnets to attract and connect. 5. Ask students what will happen if you remove the second magnet and replace it on the dowel after you turn it over. Perform that task and notice how the second magnet floats above the first. 6. Raise the second magnet several inches and release it. You will see how the magnet bounces as if it were on a spring (it is on the spring – the magnetic field is acting like a spring). 7. Continue to add additional magnets such that they all repel. All of them will float above the ones below. Pushing on the top magnet will move all the magnets down, but they will resist touching each other. 8. Press the top magnet down so that all the magnets are forced to touch. Release the top magnet and all the other magnets should spring back into place. Exploring Magnets and Magnetism 20 Dec 1999 15 Activity: Magnetic fishing game Objectives: Fun, motor skills, Materials: Paper and paper clips for fish. Rod, string, and magnet for fishing rod. Preparation: 1. Have students create and color their own fish or other sea life. See examples following this section. 2. Place a paper clip on the mouth of the fish, glue in place if desired. 3. Create one or more fishing poles for students to share. Poles consist of some type of light but strong rod (stick) with a string attached to the end. A magnet is placed at the end of the string and acts as the “hook” to grab the fish. This work is usually performed by the instructor outside of class. Activity: 4. Place fish on the floor or in a bucket. Have students stand back behind a physical barrier that prevents them from approaching the fish. They may or may not be restricted from viewing the fish depending on intent of the activity. 5. Have students hold the rod and attempt to navigate the magnet on the string to pick up the fish. Variations of this activity include competition for who can pick up the most fish with the magnet. Count and keep track of how many are picked up by each student. arranging the fish on the floor and having the student try to pick up only his or her fish (without picking up others) or a particular type of creature. the instructor creates one or more a “yucky or bad” fish, often colored brightly. These are placed in the pile with students fish. The goal is for the student to pick up a good fish without also grabbing a bad fish. Exploring Magnets and Magnetism 20 Dec 1999 16 Exploring Magnets and Magnetism 20 Dec 1999 17 Exploring Magnets and Magnetism 20 Dec 1999 18 Exploring Magnets and Magnetism 20 Dec 1999 19 Exploring Magnets and Magnetism 20 Dec 1999 20 Activity: Paperclip pickup Objectives: Have students count the number of paperclips each magnet can pick up as a measure of how strong various magnets are. Have them conclude the size of the magnet doesn’t determine the strength of the magnet. Expose them to another use of a table. Materials: Various magnets, enough paperclips such that the strongest magnet selected cannot pick them all up, chart with magnet number or name and position to record the number of paperclips each picks up. Preparation: 1. Prepare blank chart to record results during the experiment. See following example. 2. Decide if each student will have a different magnet to test or if each student will perform the test with all the magnets you’ve selected. If you choose the latter, then students can compare results. 3. Decide the manner in which the magnets will be placed into the pile of paperclips. If one pole is used to pick up magnets, it will pick up less than if both poles are used to pick up magnets. 4. Decide how many magnets will be used depending on the attention span of the students, item number two above, and time available for the activity. Activity: 5. Place paperclips in a pile on wooden table or other non-metal surface. 6. Have student either hold the magnet and place it over the pile to pick up paperclips, or set the magnet into the pile of paperclips, move it around, and then pick up the magnet where paperclips are not attached. 7. Move the magnet and paperclips that are attached to a different part of the table. Have students remove the paperclips and count them. Record the number of magnets on the chart. 8. Return the paperclips to the pile and repeat for the number of magnets you’ve decided to use. Exploring Magnets and Magnetism 20 Dec 1999 21 Magnet number or description Exploring Magnets and Magnetism Number of paperclips 20 Dec 1999 22 Activity: Identify household and workplace uses of magnets Objectives: Have students household and workplace use of magnets. Materials: None. Preparation: 1. Have discussion about magnets or activities in which students have participated in use of magnets. 2. Have collected pictures or examples of household or workplace use of magnets to share with students when they return with their homework. Activity: 3. Assign students homework of identifying where magnets are used in their home. 4. Optionally assign students homework of identifying where magnets are used in the workplace. This may beyond Kindergarten level. 5. Have discussion in class about magnet use that students have identified. Show pictures or examples of these uses. 6. Optionally, identify where in the classroom magnets are used. Examples: Examples of home magnet use are: refrigerator door seals, cabinet door latches, refrigerator magnets, tools, magnets on electric can openers that hold up the lid being opened, magnets in some thermostats, and toys that use magnets. Examples of workplace magnet use are: huge electromagnets that can pick up cars, paperclip holders with magnetic tops, magnetic levitation (mag-lev) trains float on a cushion of magnetic fields, recycling machines separate out some metals from trash with magnets. Possibly non-obvious uses of magnets are: video and audio tape (their surface is magnetic), magnetic latches on locks on doors can hold thousands of pounds, cow magnets, and magnets are inside most speakers. Exploring Magnets and Magnetism 20 Dec 1999 23 Activity: Using compasses to detect a nearby magnet Objectives: Have students understand that compasses are magnets that can move in a circle and that external magnets can make them move. (The concept of the Earth’s magnetic field is too advanced for most kindergarten students.) Materials: Mini-compasses or other compasses. Preparation: 1. Note that compasses are usually fairly delicate instruments that detect magnetic fields thousands of times smaller than those produced by bar or ceramic magnets. It is likely that one could damage a compass if a strong bar magnet was brought too close. Therefore prepare to instruct students to keep the magnets from coming close to the compasses. 2. Note that the mini-compasses are fairly crude and therefore will not detect a magnet’s field from as far as a more expensive model compass. 3. Students should have had time to self-explore with magnets. Activity: 4. Place several mini-compasses out on a non-ferrous table (wood, etc.). Check to see that they are all detecting generally the same direction as north. If not, either one or more of the compasses are damaged or a magnet is too close. 5. Explain to students that the needle inside the compass is a tiny magnet that can spin around freely. If a magnet is brought nearby, it will point toward the magnet. 6. Let students look and hold the compasses. 7. Place the compasses back on the table. Ask students to watch the needles in the compass to see if they move as you slowly bring a bar or ceramic magnet closer and close. You may wish to rotate the magnet from side to side slightly and slowly as you do this to make movement in the compasses more obvious. 8. Bring the magnet close enough so the movement is obvious. Explain to the students that the magnet cannot be brought much closer without damaging the compasses. 9. Try different magnets. Have each student hold a magnet and bring it closer. 10. Option: A more advanced experiment could be performed for a number of magnets. This procedure would be preformed and the distance between the compass and magnet is measured for each magnet. Stronger magnets should affect the compass from longer distances than week magnets. Exploring Magnets and Magnetism 20 Dec 1999 24 Activity: What items do magnets attract? Objectives: Have students understand the types of materials that magnets will attract (usually metal, but not all types of metal) and other magnets. Materials: Various samples of materials from around the classroom or home. Of particular interest is having a selection of metals that magnets will and will not attract. Most U.S. coins are not magnetic and aluminum is not magnetic. Preparation: 1. Collect various items from around the classroom or home that the students can experiment with magnets. Suggested items include plastic, paper, wood, coins, aluminum, steel or iron objects, cloth, cup of water, and clear plexiglass, another magnet. 2. Select the magnets that will be used to test the properties of material 3. Copy or generate a chart for recording results of the experiment (see following example). 4. Students should have had free time to explore magnets. Activity: 5. Set the items on a table for students to explore. Explain that each item will be tested to determine if they are attracted to magnets. 6. For each item to be tested, ask the students if they think the magnet will attract the objects. 7. Then, have a student take the magnet and slowly approach the object to see if the object moves and is attracted to magnets. Rotate students for each item. 8. Record the results on the chart by entering the object name and YES or NO. 9. Repeat for all items to be tested. 10. When completed, ask the students to speculate about what kinds of objects are usually attracted to magnets. Generally this should be some metals and other magnets. 11. Option: Another variant of this experiment will have same sized and shaped objects (such as a rectangle) of the materials or different color materials of the same type. These can be tested to show that shape and color do not determine if an object is attracted to magnets. Exploring Magnets and Magnetism 20 Dec 1999 25 Do magnets attract it? YES or NO Name of item tested Exploring Magnets and Magnetism 20 Dec 1999 26 Activity: Make a magnet Objectives: Demonstrate that you can make a magnet from some materials, in this case, a nail. Materials: Several large wood nails, strong magnet, paperclips. Preparation: 1. Make sure the nail is not already magnetized by trying to pick up paperclips with it. 2. Try this experiment before class time to make sure the type of nails you’ve obtained are able to be magnetized. Activity: 3. Place paperclips on table. Demonstrate that the nail cannot pick up paperclips like a magnet. Demonstrate that a magnet can pick up the paperclips. 4. Indicate that you will turn the nail into a magnet for a short time by stroking the nail with the magnet. 5. Stroke the nail with the magnet about 50 times. Place one pole of the magnet next to one end (starting end) of the nail, then move the magnet quickly along the length of the nail. At the end of each stroke, move the magnet a short distance away from the nail while brining it back to the starting end. (Stroke in one direction only.) Repeat about 50 times. 6. Demonstrate that the nail is magnetized and is now able to pick up paperclips. 7. Optional: If you tap the nail on a hard object repeatedly, it will likely loose its magnetic qualities as the magnetic domains in the nail are randomized. The nail will then no longer be able to pick up paperclips. Exploring Magnets and Magnetism 20 Dec 1999 27 Activity: Move a object without touching it Objectives: Show students that magnets can move objects through solid materials such as a wood table or sheet of plastic. Show students that this magnetic effect can be used in magic tricks and every day applications. Materials: One or two strong magnets, a piece of metal that magnets attract (paperclips). Two identical small paper drawings that you can fold in half to make a pocket for magnets. Bag or box to hide the two drawings inside out of view of students. Preparation: 1. Hide a magnet inside a small light-weight common object that is not magnetic (paper drawing suggested above, but other items could be used. Prepare another identical item that doesn’t have a magnet inside. 2. Students should have had time to self-explore with magnets and paperclips. Activity: 3. Place paperclips on table and talk to the students about some related subject while you inconspicuously hold a magnet below them under the tabletop. Move the paperclips around a bit with the magnet until students notice. 4. Ask them why the paperclips are moving. If they don’t discover your trickery, explain it to them. 5. Ask them to try moving the paperclips in the same way you did. Explain how magnets can attract metal through other objects like wood, paper, and plastic. 6. Option: You could stop here. 7. Ask them to move one of the paper drawings you prepared (the one without a magnet) in the same way. Take it out of the box and put it on the table for their attempt. They will hopefully fail in their attempt and conclude that magnets cannot attract paper. Pick up the drawing and put it in the box with the other drawing. 8. Pull out the drawing (with the magnet) and show them that you can move the drawing with a magnet. Quickly place it back in the box so they cannot explore it. 9. Let them try again with the drawing without a magnet. 10. Ask them why you could move it and they couldn’t. 11. Bring out the second drawing with the magnet inside to show them there are two drawings. Let them explore, hold, and use magnets on both of them. 12. See if they discover your trickery. If not, explain to them that one paper drawing contains a hidden magnet. Explain that this was like a magic trick and the secret was that one drawing contained a magnet. Exploring Magnets and Magnetism 20 Dec 1999 28 Activity: Make a paperclip float in air Objectives: Show students how magnets can attract an object and suspend it without actually touching it. Materials: Large paperclip, fine thread (sewing thread) that is light-weight, strong magnet, object to hold magnet firmly suspended above table (such as a wood ruler or yardstick), tape to hold magnet to this object, heavy object to hold string down (like a book), small piece of paper and metal. Preparation: 1. Tie thread to paperclip. 2. Arrange for magnet to be firmly suspended a foot or two above the table. Activity: 3. Show students that the paperclip is attracted to the strong magnet and that the paperclip sticks to the magnet. 4. Hold pull paperclip by the string and show them that the paperclip will be attracted to the magnet even when it is not touching and that the string will be taut. 5. Suspend the magnet a food or two above the table. Place paperclip on the magnet. Place string under the book so the free end is accessible. 6. Pull on the string so the string between the paperclip and book is taut. Pull a bit more so that the paperclip is away from the magnet, floating in air. This can be tricky. 7. Show students that if paper is placed between the paperclip and magnet that the paperclip remains suspended (paper does not disrupt the magnetic field). 8. Place a piece of metal between the magnet and paperclip. The paperclip should fall for ferrous metals. MAGNET paperclip BOOK String Exploring Magnets and Magnetism 20 Dec 1999 29 Activity: Make your own refrigerator magnets Objectives: A craft project using magnets. Materials: Thin sheets of magnetic material. These can be obtained through scientific supply stores or commercial sign-making companies (that make signs to be applied temporarily to the outside of vehicles). Alternatively, one could purchase a number of strong small magnets to glue to various craft projects. Preparation: 1. Determine what craft project will be used to take advantage of this activity. Suggestions include making name tags, seasonal projects, cutting material to fit small class pictures or drawings. The thin “refrigerator magnet” material can easily be cut to shape and is particularly good for backing entire pictures or small drawings. Strips of it may also be cut and applied to the back of larger projects; however, the material is typically not strong enough to hold much weight in this configuration. Activity: 2. Have students generate craft project. 3. Glue magnets to the project and let dry. Exploring Magnets and Magnetism 20 Dec 1999 30 Activity: See a magnetic field Objectives: See a magnet’s magnetic field by using iron filings. This is usually an interesting experiment for older children; however, for younger children it can be very messy. The kit includes a “Mysterious Magnetic Tube” which holds iron filings in a clear cylinder that is structured to allow a bar magnet (cow magnet) to be inserted in the middle. For younger children, the objective is to expose them to iron filings and magnets so they can see the shapes the iron filings take. Materials: Mysterious Magnetic Tube Preparation: 1. None, or read directions that came with the Mysterious Magnetic Tube. Activity: 2. Explain that inside the tube contains small pieces of metal called iron filings. These particles are attracted to magnets. They are like very little paperclips. 3. Without the magnet, show the students the powdered metal filings in the tube. 4. Insert the magnet, hold your fingers over both ends and shake the iron filings around inside. Let the students see the shapes that the iron filings take as they are attracted to the magnet. 5. Ask them what will happen when you take the magnet out of the tube. Then remove the magnet. Exploring Magnets and Magnetism 20 Dec 1999 31 References Concepts for this document were augmented by the following sources on the world wide web: 1. http://windows.engin.umich.edu/spaceweather/sun_earth10.html 2. UtahLINK, http://www.uen.org/utahlink/, Utah State Office of Education 3. Stick To It!, Original Lesson on Magnets, by:Zandra Jackson 4. Various coloring book image web sites. Exploring Magnets and Magnetism 20 Dec 1999 32