Magnetic Fields Tuesday, 18 June 2019 Learning Objective: To plot the shape of magnetic fields and understand how they behave. Do now: Without your books can you recall the names of the following symbols. Learning Journey: 2. Can you correctly put all of the symbols into a series and parallel circuit. Explain the difference between permanent and induced magnets. A V Keywords: Permanent, Induced, Plotting compass, Bar magnet, Describe how magnets affect each other. Describe the uses of permanent and temporary magnetic materials. Plot the shape of magnetic fields using plotting compasses and describe variations in strength. Explain how a magnetic compass can be used as evidence for the Earth’s magnetic core Did you get them right? Series Circuit Parallel Circuit A V A V What is the scientific name for this occurrence? Permanent and induced magnets https://www.youtube.com/watch?v=sRyy7-jEu3Q Watch the clip and answer the following questions… 1. State what happens when you put the opposite poles of a magnet next to each other? 2. State What happens when you put the same poles next to each other? 3. Explain how we know magnets produce a non-contact force. 4. Explain why a nail is considered an induced magnet. Permanent and induced magnets Self assess your answers using RED Pens. 1. State what happens when you put the opposite poles of a magnet next to each other? They will be attracted to each other. 2. State What happens when you put the same poles next to each other? They repel each other. 3. Explain how we know magnets produce a non-contact force. The magnets do not have to touch to experience a force or cause a force on something else. 4. Explain why a nail is considered an induced magnet. A nail would not be magnetised unless it is close to a permanent magnet. When it is near a permanent magnet it becomes magnetic. How do magnets actually work? • https://www.youtube.com/watch?v=hcORdjvx vDg Compare and contrast permanent and induced magnets and Explain how an induced magnet can be more useful. Use the following key words: Permanent, Magnetic field, Induced, Turned off, _________________________________________________ _________________________________________________ _________________________________________________ _________________________________________________ _________________________________________________ _________________________________________________ WAGOLL Add any missing information to your answer using RED pen. A permanent magnet produces its own magnetic field which cannot be turned on or off, it is there all the time. On the other hand, an induced magnet only become a magnet when it is placed in a magnetic field this means it can be turned on and off by moving the permanent magnet closer or further away. This is useful in scrapyards for moving large pieces of metal. Magnetic Fields The region around a magnet where it has a magnetic effect is called its magnetic field. When a magnetic material is placed in a magnetic field it will experience a force. What do these magnetic fields look like? magnetic field Plotting a magnetic field 1. Place a bar magnet on a plain piece of paper and draw around it. 2. Place a plotting compass at one end of the bar magnet. The north pole of the plotting compass is attracted to the south pole of the bar magnet (in this case). 3. Draw in a small arrow head with a pencil next to the south pole of the plotting compass. Plotting a magnetic field 4. Place the compass so that the north pole of the compass now points to the pencil mark you have just made. Draw another point next to the south pole of the compass. 5. Move the compass again, placing it so that the north pole points to previous pencil mark. Repeat this process until the compass is next to the north pole of the magnet. Plotting a magnetic field 6. Now join up all of the points with a smooth curve using a pencil. 7. The line you have drawn is called a field line. Add an arrow to this field line to show the direction of the magnetic field, which is always north to south. Plotting a magnetic field 8. Repeat the process with the plotting compass, this time place the compass closer to the bar magnet. Draw in another field line and add the direction of the field again. This is what your magnetic field should look like now that you have complete one side of your magnetic field If you keep repeating the process several times on each side of the magnet you will end up with a clear picture of the magnetic field around the bar magnet. It is important to remember however, The magnetic field of a magnet is all around the magnet Using your knowledge about how magnetic fields behave, draw and describe how a magnetic field will behave when you have… • Two North poles facing each other. • A North and South Pole Bar Magnet facing each other. Did you get them right? Correct your diagrams if you didn’t. Evidencing the earths magnetic core • Think, pair, share: why do you think the bar magnet in a compass will always point north even when there is not a magnet nearby? • Lets find out… https://www.youtube.com/watch?v=FodEDHaEY68 Compasses Which way does a compass point? Compasses point: • North (geographically) • South (magnetically) Extension: Watch the following clip and explain how Aurora Borealis occurs. http://www.youtube.com/watch?v=PaSFAbATPvk&feature=related Aurora borealis The ____________occurs when charged particles flowing out from the ___ sun become _______ magnetic field and enter trapped by the Earth’s _______ Earth’s atmosphere near the ______ North pole. the _______ These particles ______ Collide with atoms in the near gain energy. This atmosphere, and the atoms ____ energy is then emitted by the atoms as _____. light _____ Plenary: Fill in the following table with a tick I can do this Describe how magnets affect each other. Explain the difference between permanent and induced magnets. Describe the uses of permanent and temporary magnetic materials. Plot the shape of magnetic fields using plotting compasses and describe variations in strength. Explain how a magnetic compass can be used as evidence for the Earth’s magnetic core I can do this with help I don’t know
