Magnetism Workbook & Notes - Canizares

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1 Magnetism Workbook & Notes - Canizares Name Hour Learning Objectives: Cornell/Mark the Text Requirements: Magnetism Define magnet, magnetic force, magnetic field, & poles Explain the interactions of magnets using the terms above & be able to predict interactions. Explain how atomic structure creates a magnet & how magnets are made/changed Explain how Earth s magnetic field was created and the effects of it. Grading Guide for Mark the Text: Paragraphs numbered Vocabulary Circled or Highlighted Each Paragraph has key ideas Underlined or Highlighted Underlines or Highlights are 5-8 words (less is best) Grading Guide for Cornell Notes: Big Topic ID ed Essential Question based on big topic & higher level question (hint use how) Notes per paragraph using mark the text Question per paragraph on left Summary is 5 sentences minimum and is about the entire reading Summary is factual not personal Notes are processed highlight most difficult,! *?etc. --Grading Rubric Activities Completed & accurate Answers show evidence of thinking and improvement of understanding on magnets Work is neat and shows effort/time spent Corrections made on mistakes (except I think type questions/predictions) Almost perfect several many most Cornell Notes & Mark the Text Checklist above is completed It s evident that it has been used for studying at home revised, foldings for using questions, etc. Almost perfect several many most

2 Intro to Magnets Activity 1: Magnetic Fields Teacher Demo Draw the magnetic field: N Other Observations Made: 1-2- Activity 2: What s Attractive? Using the magnets & materials provided, see which items are attracted to the magnet? Circle Yes if Attracted. For the last 3 pick your own objects Cork Yes No Red Rock/Scoria Yes No PaperClip Yes No Copper Cylinder Yes No Popsicle Stick Yes No Dropper Yes No Penny Yes No Aluminum Foil Yes No Brass Fastener Yes No Battery Yes No Marble Yes No Yarn Yes No Clothespin Yes No Rubber Band Yes No Cottonball Yes No Stopwatch Yes No Yes No Yes No Yes No Based on your observations, what materials do you think magnets are attracted to?. The observations I made to justify this are Activity 3: Opposites Attract Doughnut Magnets Using the edge of table or a your nail, gently slide the doughnut magnets into two groups. Flip them around & see what happens. Describe what the repulsion force feels like to you. Using the doughnut magnets & pencil, try to stack them (I bought strong magnets so will be hard be gentle they are cheap) so they aren t touching each other. How many could you do? Why do you think one side attracts and one side repels? Guess. Activity 4: Bar Magnets Try to line up 2 magnets to push another magnet without touching. What did you have to do get it to work? I had to. Take 2 bar magnets. Which sides attract (use N &/or S) tip to tip? sides repel? How do you need to arrange the magnets so that they stick together side by side? repel? Do your own investigations and write down one magnet observation: Sentence Summary of What You Learned About Magnets (even if a repeat): p. 1

3 Magnetic Fields and the Earth PhET link on wp 1. Pre-Thinking: Based on your prior knowledge of compasses, how do they work? What does that tell you about the planet Earth? 2. Deselect all the options from the menu to the right using the boxes. You should see just the bar magnet as shown below: 3. Make a prediction in your head: What do you think the magnetic field produced by the magnet will look like (similar to the iron sprinkles we did in class). 4. Check your prediction by selecting the show field tab. On the magnet drawing above, sketch the field. 5. Make a prediction: If you were to chop this magnet in half and separate the pieces, what would be the polarity (N, S or both) of each piece? 6. Select show inside magnet. Do you still agree with your prediction? Why or Why not? 7. Deselect Show Field. Predict in your head - If you place a compass near the magnet, what will the compass do? 8. Select Show Compass. The red arrow of the compass points initially points: 9. Move the compass to several positions around the magnet. In the space below, sketch the red compass needle point in at least 8 different positions as you see it placed around the magnet. S S 10. Select Show Field. Place the compass at the positions you used for the sketch before. What do you N N notice? 11. Based on what you have just seen, what do you think is the polarity of the North seeking end of the compass needle? North or South Why: opposites attract or likes attract 12. If you are lost in the woods, and you have a compasswould you want to hold it near a magnet as you are trying to find your way? Why or Why not?, because 13. Select show planet Earth. Are the North and South poles where you expect them to be? Why? 14. Move the compass to various positions around the Earth. Does this confirm your guess about how compasses work? 15. Does a magnet have to be touching another material to exert a force? Why or why not? 16. If you were pushing the like poles of two magnets together, what happens as they get closer and closer? 17. Make a prediction: Based on what you have learned about magnets, and from other natural laws, would you expect magnetic fields to be stronger closer to the magnet, or farther away? 18. Select Show Field Meter (can deselect show earth ). Magnetic field strength is sometimes measured in Gauss (G). Move the blue meter to at least 6 locations. Was your prediction right? Review: Like poles, while unlike poles. (Word Choice: attract or repel) If you attach a magnet to a string so that the magnet is free to rotate, you will see that one end of the magnet will point a. north b. southwest c. east d. west The Earth behaves like a large magnet. True or False Magnetic field lines flow a. in no recognizable pattern. b. from one pole to another. c. from the center of a magnet outwards. d. from the poles to the center of the magnet. p. 2

4 NOVA: Magnetic Storm 1. How far down is the Earth s core? 2. What is the Earth s core made of? 3. The Earth s is generated in the core. 4. What have scientists recently discovered about the field? 5. The is created deep in the Earth s core. It streams out near the, loops around the planet, and then runs back into the core near the. 6. The magnetic field protects us from from space. 7. Every few hours, the ejects billions of tons of charged particles the solar. 8. The only evidence of the particles hitting the magnetic field are the and lights. 9. In 1996, NASA sent a satellite to. 10. Does Mars currently have a magnetic field? 11. There is a way rocks can be when they form. If molten rock cools in a strong, iron based minerals in it can pick up that magnetism and the resulting solid rock will itself be. 12. Mars began to lose its water and atmosphere about years ago. 15. In years, the field has decreased %. 16. It s really inside the Earth s core that gives rise to the magnetic field. 17. The liquid metal in the core is in constant. 18. Mars may have lost its magnetic field because its core and became solid. 19. Why don t scientists think that Earth s core cooling down is the cause of the decrease in strength of our magnetic field? 20. Going back about 700,000 years, the Earth s magnetic field was. 21. On average, reversals happen once every years. 22. On the computer simulation, every time a field reversal was about to happen, the strength of the magnetic field would. 23. Eighteenth and nineteenth century sailors had to know the difference between north and north. 24. During the weakened state of the magnetic field, the Earth may have as many as magnetic poles. 25. About people per year would die as a result of increased exposure to radiation. 26. It might be possible to see the every night. Label the Diagram: Earth, magnetosphere, solar wind 13. Clay contains tiny particles of a mineral called. 14. Clay does not become magnetic until it is and cooled. p. 3

5 Imagine zooming along in a train that glides without even touching the ground. You feel no vibration and hear no noise from the steel tracks below. You can just sit back and relax as you speed toward your destination at nearly 500 kilometers per hour. Are you dreaming? No, you are floating a few centimeters in the air on a magnetically levitating train, or maglev train. Although you have probably not ridden on such a train, they do exist. What makes them float? Believe it or not, it is magnetism that makes them float. Properties of Magnets When you think of magnets, you might think about the objects that hold notes to your refrigerator. But magnets can also be found in many other everyday items such as wallets, kitchen cabinets, and security tags at a store. A magnet is any material that attracts iron and materials that contain iron. Rocks containing magnetite attracted materials that contained iron. They also attracted or repelled other magnetic rocks. The attraction or repulsion of magnetic materials is called magnetism. About a thousand years ago, people in other parts of the world discovered another property of magnetic rocks. If they allowed such a rock to swing freely from a string, one part of the rock would always point in the same direction. That direction was toward the North Star, Polaris. This star is also called the leading star, or lodestar. For this reason, magnetic rocks are known as lodestones. Magnetic Poles The magnets in your everyday life have the same properties as magnetic rocks because they are made to have them. Recall that one end of a magnet always points north. Any magnet, no matter what its shape, has two ends, each one called a magnetic pole. The magnetic effect of a magnet is strongest at the poles. The pole of a magnet that points north is labeled the north pole. The other pole is labeled the south pole. A magnet always has a pair of poles, a north pole and a south pole. Magnetic Interactions What happens if you bring two magnets together? The answer depends on how you hold the poles of the magnets. If you bring the north pole of one magnet near the south pole of another, the two unlike poles attract one another. However, if you bring two north poles together, the like poles move away from each other. The same is true if two south poles are brought together. Magnetic poles that are unlike attract each other, and magnetic poles that are alike repel each other. Magnetic Force The attraction or repulsion between magnetic poles is magnetic force. A force is a push or a pull that can cause an object to move. A magnetic force is produced when magnetic poles interact. Any material that exerts a magnetic force is considered to be a magnet. The maglev train you read about earlier depends on magnetic force to move. Magnets in the bottom of the train and in the guideway on the ground have like poles facing each other. Because like poles repel, the two magnets move away from each other. The result is that the train car is lifted up, or levitated. Other magnets make the train move forward. Magnetic Fields A magnetic force is strongest at the poles of a magnet, but it is not limited to the poles. Magnetic forces are exerted all around a magnet. The area of magnetic force around a magnet is known as its magnetic field. Because of magnetic fields, magnets can interact without even touching. Magnetic field lines are invisible lines that map out the magnetic field around a magnet. Magnetic field lines spread out from one pole, curve around the magnet, and return to the other pole. The lines form complete loops from pole to pole and never cross. Arrows are used to indicate the direction of the magnetic field lines always leaving the north pole and entering the south pole. The distance between magnetic field lines indicates the strength of a magnetic field. The closer together the lines are, the stronger the field. A magnet s magnetic field lines are closest together at the poles. p. 4

6 Big Topic: Essential Question: Question Per Paragraph/Idea: Notes What s an example of how magnets are used? Properties of Magnets What s a magnet? 1: 2: : any material that attracts iron and materials that contain iron What are lodestones? Magnetic Poles What s a magnetic pole? Magnetic Interactions Which poles attract & which repel? Magnetic Force What s a magnetic force? 3: are magnetic rocks that when swinging freely, one point will always point in the same direction 4: Magnetic Pole: 5: 6: : the of attraction or repulsion between poles Magnetic Fields What s a magnetic field? What do field lines look like around a magnet? 7: Magnetic fields: 8: Magnetic field lines spread out from to p, curving around the magnet; the distance between the field lines indicates the s of the field Summary (5 sentences minimum): Magnets are Each end of a magnet is called a. Magnets always have a p of poles. The poles that are alike each other, and the ones that are opposite each other. The attraction or repulsion between magnetic poles is called the m f. While magnetic fields are p. 5

7 The Atom The magnetic properties of a material depend on the structure of its atoms. Because materials take up space and have p. 2 mass, they are classified as matter. All matter is made up of atoms. An atom is the smallest particle of an element that has the properties of that element. An element is one of about 100 basic materials that make up all matter. The structure and composition of the atoms that make up a particular element make that element different from any other element. Structure of an Atom Although atoms can differ, they have some characteristics in common. Every atom has a center region and an outer region. The center region of an atom is called a nucleus. Inside the nucleus two kinds of particles may be found: protons and neutrons. A proton is a particle that carries a positive charge. Aneutron is a particle that does not carry a charge. The outer region of an atom is mainly empty space. However, particles called electrons usually exist there. An electron is a particle that carries a negative charge. Electrons move randomly throughout the atom. They are much smaller than neutrons and protons. Electron Spin Each electron in an atom has a property called electron spin, so it behaves as if it were spinning. A spinning electron produces a magnetic field that makes the electron behave like a tiny magnet in an atom. In most atoms, electrons form pairs that spin in opposite directions. Opposite spins produce opposite magnetic fields that cancel. Therefore, most atoms have weak magnetic properties. But some atoms contain electrons that are not paired. These atoms (like iron and nickel) tend to have strong magnetic properties. Making and Changing Magnets A magnet can be made from ferromagnetic material. However, no magnet can last forever. Magnets can be made, destroyed, or broken apart. Making Magnets People make the magnets you use every day. Some unmagnetized materials can be magnetized. A magnet can be made by placing an unmagnetized magnetize-able material in a strong magnetic field or by rubbing the material with one pole of a magnet. You can magnetize the paper clip by rubbing in one direction with one pole of a magnet. The magnetic field of the magnet causes some domains in the paper clip to line up in the same direction as the domains in the magnet. The more domains that line up, the more magnetized the paper clip becomes. It can hold the magnetism temporarily. Some materials hold the magnetism for a long time. Destroying Magnets Like a temporary magnet, a permanent magnet can also become unmagnetized. One way for a magnet to become unmagnetized is to drop it or strike it hard. If a magnet is hit hard, its domains can be knocked out of alignment. Heating a magnet will also destroy its magnetism. When an object is heated, its particles vibrate faster and more randomly. These movements make it more difficult for all the domains to stay lined up. Above a certain temperature, every ferromagnetic material loses its magnetic properties. The temperature depends on the material. Breaking Magnets What happens if you break a magnet in two? Do you have a north pole in one hand and a south pole in the other? The answer is no you have two smaller magnets. Each smaller magnet has its own north pole and south pole. If you break those two halves again, you have four magnets. p. 6

8 Big Topic: Essential Question: Question Per Paragraph/Idea: Notes The Atom Structure of an Atom Electron Spin Making & Changing Magnets Making Magnets Destroying Magnets Breaking Magnets 1:Matter is made of a, which if they are the same make up e. 2:_In the center of the atom (n ) you can find the protons (p charge) & the n (no charge). 3: : can be found spinning around the outside of the nucleus ( charge). 4: 5: I has electrons that are not paired producing strong magnetic fields 6: Magnets can be made, destroyed, or broken apart. 7:You can magnetize a paperclip by 8:You can destroy the magnetization by 9:When a magnet is broken it Summary (5 sentences minimum): Atoms are the basic building blocks of all matter. Each atom contains a protons ( charge), n (no charge), and around the outside (negative charge). Magnetic fields are creating due to the spinning e. Magnets can be m, d or broken apart. Magnets can be destroyed by When magnets are broken p. 7

9 Earth as a Magnet When Christopher Columbus sighted land in 1492, he didn t know what he had found. He was trying to find a shortcut from Europe to India. Where he landed, however, was on an island in the Caribbean Sea just south of the present-day United States. He had no idea that such an island even existed. In spite of his error, Columbus had successfully followed a course west to the Americas without the help of an accurate map. Instead, Columbus used a compass for navigation. A compass is a device that has a magnetized needle that spins freely. A compass needle usually points north. Earth acts as a giant magnet. Just like a bar magnet, Earth has a magnetic field surrounding it and two magnetic poles. The fact that Earth has a magnetic field explains why a compass works as it does. The poles of the magnetized needle on the compass align themselves with Earth s magnetic field. Earth s Core Gilbert thought that Earth s center, or core, contains magnetic rock. Scientists now think that this is not the case, since the material inside Earth s core is too hot to be solid. Also, the temperature is too high for the material to be magnetic. Earth s magnetism is still not completely understood. But scientists do know that the circulation of molten material in Earth s core is related to Earth s magnetism. Earth s Magnetic Poles You know that Earth rotates on its axis, around the geographic poles. But Earth also has magnetic poles. These magnetic poles are located on Earth s surface where the magnetic force is strongest. The magnetic poles are not in the same place as the geographic poles. For example, the magnetic pole in the Northern Hemisphere is located in northern Canada about 1,250 kilometers from the geographic North Pole. Magnetic Declination If you use a compass, you have to account for the fact that Earth s geographic and magnetic poles are different. Suppose you could draw a line between you and the geographic North Pole. The direction of this line is geographic north. Then imagine a second line drawn between you and the magnetic pole in the Northern Hemisphere. The angle between these two lines is the angle between geographic north and the north to which a compass needle points. This angle is known as magnetic declination. So, magnetic declination differs depending on your location on Earth. The magnetic declination of a location on Earth today is not the same as it was 10 years ago. The magnetic declination of a location changes. Earth s magnetic poles do not stay in one place as the geographic poles do. The diagram shows how the location of Earth s magnetic pole in the Northern Hemisphere has drifted over time. Earth s Magnetic Field You learned that a material such as iron can be made into a magnet by a strong magnetic field. Since Earth produces a strong magnetic field, Earth itself can make magnets out of ferromagnetic materials. This can happen to some everyday objects. So even though no one has tried to make metal objects such as file cabinets in your school into magnets, Earth might have done so anyway! Earth s magnetic field also acts on rocks that contain magnetic material, such as rock on the ocean floor. When the rock is molten, the iron it contains lines up in the direction of Earth s magnetic field. p. 8

10 Copy or Rephrase the Question You Missed Why Did You Miss It? Had no clue & guessed I confused it with something else: Brain Fart/Silly Mistake Other: Correct Answer (Do NOT write the letter choice) Had no clue & guessed I confused it with something else: Brain Fart/Silly Mistake Other: Had no clue & guessed I confused it with something else: Brain Fart/Silly Mistake Other: Had no clue & guessed I confused it with something else: Brain Fart/Silly Mistake Other: Had no clue & guessed I confused it with something else: Brain Fart/Silly Mistake Other: p. 9