Published on

Published in: Education, Technology, Business


  1. 1. MAGNETS
  2. 2. <ul><li>Are there magnets in nature? </li></ul><ul><li>What is magnetic in nature? </li></ul>
  3. 3. 1st Experiment <ul><li>Which objects will stick to the magnet? </li></ul><ul><li>Nails </li></ul><ul><li>Scissors </li></ul><ul><li>Plastic caps </li></ul><ul><li>Coins </li></ul><ul><li>Wooden counters </li></ul><ul><li>clips </li></ul>
  4. 4. <ul><li>Magnets represent an amazing world which we can´t see. </li></ul>
  5. 5. <ul><li>Our senses don´t pick up on magnets but thanks to Science we can understand them. </li></ul>
  6. 6. <ul><li>Do you know that magnets are one of the most important forces which move our world? </li></ul><ul><li>There is a magnet or and electromagnet inside an electric engine. </li></ul>
  7. 7. <ul><li>The Earth, the sun and the stars produce a magnetic field which we can detect and study. </li></ul>
  8. 8. <ul><li>Computers store data in magnetics CDs. </li></ul>
  9. 9. <ul><li>Doctors can see the inside of our bodies thanks to magnetic resonance. </li></ul>
  10. 10. <ul><li>Einstein said in his autobiography that when he was five years old he was very surprised when his father gave him a compass as a present. </li></ul>
  11. 11. <ul><li>Would you like to be surprised by magnets? </li></ul>
  12. 12. 2nd Experiment <ul><li>How can we measure </li></ul><ul><li>the strength of a </li></ul><ul><li>magnet? </li></ul>
  13. 13. <ul><li>Let´s learnt about magnets! </li></ul><ul><li>We will follow the historical path. </li></ul>
  14. 14. <ul><li>We will discover through history how magnets and electricity joined and scientists changed their ideas and their explanations about magnets. </li></ul>
  15. 15. <ul><li>Pliny The Elder (23-79), </li></ul><ul><li>the Natural Historian, </li></ul><ul><li>  described the </li></ul><ul><li>magnetite rock and he told </li></ul><ul><li>about the Magnes </li></ul><ul><li>shepherd´story: </li></ul>
  16. 16. <ul><li>There is a story that a shepherd from the island of Grete was the first to discover lodestone when </li></ul><ul><li>his crook, which </li></ul><ul><li>had an iron tip, </li></ul><ul><li>was pulled towards </li></ul><ul><li>a stone when he </li></ul><ul><li>passed over it. </li></ul><ul><li>The shepherd ´s name was Magnes. </li></ul>
  17. 17. Platon (fouth century before Christ) <ul><li>The stone not only attracts iron rings, the stone transmits its power to attract other rings. Sometimes we can see many iron objects joined with others like a chain, and all of them receive the power of the stone. </li></ul>
  18. 18. We can observe <ul><li>Nails are magnetized when they touch the magnets. </li></ul><ul><li>Some objects stick to magnets. </li></ul><ul><li>Objects will pull towards the magnets.Another name for </li></ul><ul><li>sticking is &quot;attract”. </li></ul>
  19. 19. 3rd Experiment <ul><li>To magnetize nails and to observe what´s happen. </li></ul>
  20. 20. <ul><li>What are temporary magnets? </li></ul>
  21. 21. Temporary Magnets <ul><li>T emporary magnets are those which act like a permanent magnet when they are within a strong magnetic field, but lose their magnetism when the magnetic field disappears.  Examples </li></ul><ul><li>would be paperclips </li></ul><ul><li>and nails and other soft </li></ul><ul><li>iron items. </li></ul>
  22. 22. The first model of a magnetic force <ul><li>Tito Lucrecio Caro (99-55 B.C.) (Julio César´s contemporary) describes in his poem “The Rerum Natura”(The nature of the things) that he has seen pieces of iron move inside a bronze vessel when this vessel was approched by a magnetic stone. </li></ul>
  23. 23. 4th Experiment <ul><li>What are permanent magnets? </li></ul>
  24. 24. Permanent Magnets <ul><li>Permanent magnets are those we are most familiar with, such as the magnets hanging onto our refrigerator doors.  They are permanent in the </li></ul><ul><li>sense that once they </li></ul><ul><li>are magnetized, they </li></ul><ul><li>retain a level of </li></ul><ul><li>magnetism. </li></ul>
  25. 25. Tito Lucrecio Caro… <ul><li>He describes some pieces of iron which have been in contact with a magnetic stone, they are repeled when they are approched by the stone. </li></ul>
  26. 26. We discover a new force. <ul><li>Do the two ends of a magnet have the same properties? </li></ul>
  27. 27. 5th EXPERIMENT <ul><li>What are the two ends of a magnet like? </li></ul>
  28. 28. POLES <ul><li>All magnets have ends or sides. </li></ul><ul><li>Another name for these ends or sides is &quot;poles&quot;. </li></ul><ul><li>The two ends of the magnet are different. </li></ul><ul><li>The red ends are called the &quot;north pole&quot;. </li></ul><ul><li>The blue ends are called the &quot;south pole&quot;. </li></ul>
  29. 29. THE RULES <ul><li>Same colour poles repel. </li></ul><ul><li>Different colour poles attract. </li></ul>
  30. 30. 6th Experiment <ul><li>Are human beings sensitive to magnets? </li></ul>
  31. 31. <ul><li>We are not sensitive to magnets so, we need instruments to detect them and study their characteristics. </li></ul>
  32. 32. A big leap in history (XIX c.) <ul><li>Faraday introduced a new concept: </li></ul><ul><li>MAGNETIC FIELD </li></ul>
  33. 33. About Faraday <ul><li>Date :1791-1867 </li></ul><ul><li>His biggest achievement was the concept of magnetic and electric fields. </li></ul>
  34. 34. The magnet rules <ul><li>Alike poles repel each other. </li></ul><ul><li>Different poles attract each other. </li></ul><ul><li>This happens without touching them. </li></ul><ul><li>Why does a magnet know that </li></ul><ul><li>there is a magnet close? </li></ul>
  35. 35. <ul><li>Human beings have always been interested about how magnets work. </li></ul><ul><li>And human beings always thought that there was something that we couldn´t see but did exist. This something was the magnetic field. </li></ul>
  36. 36. <ul><li>The compass is the instrument which helps us to detect the magnetic field. </li></ul>
  37. 37. 7th Experiment <ul><li>Can we make a compass? </li></ul>
  38. 39. <ul><li>The Earth is a great magnet. Its magnetic field is like a bar magnet at its center. </li></ul>
  39. 40. <ul><li>The Earth is a magnet </li></ul><ul><li>because it contains a lot </li></ul><ul><li>of iron.  </li></ul><ul><li>The moon does not </li></ul><ul><li>have as much iron, so </li></ul><ul><li>it is not a magnet.  </li></ul><ul><li>Your compass would </li></ul><ul><li>not work on the moon.” </li></ul>
  40. 42. <ul><li>What is near the Geographic North Pole, a Magnetic North or a Magnetic South? </li></ul>
  41. 43. <ul><li>Think of the Earth's North Pole (which is geographically located in the artic) as the &quot;south end of a bar magnet&quot;.This is why the North tip of a compass needle is attracted to the vicinity of the &quot;North Pole&quot;. </li></ul><ul><li>As we know, with </li></ul><ul><li>magnets, &quot;opposite </li></ul><ul><li>ends attract“ </li></ul><ul><li>(N is attracted to S). </li></ul>
  42. 44. The red pole of a magnet points to the geographic North pole. <ul><li>A compass needle is a magnet too - so it's S end will be attracted to the &quot;North&quot; side of your unmarked magnet (and vice versa). </li></ul>
  43. 45. 8th Experiment <ul><li>How does a toy lift work? </li></ul>
  44. 46. 9th Experiment <ul><li>Can we make an engine work with magnets? </li></ul>
  45. 47. QUIZ TIME <ul><li>1. Which objects will not stick to the magnet? </li></ul>
  46. 48. <ul><li>2. Magnets should never be held in front of which object? </li></ul>a) Telephone b) Computers c) Books d) Light
  47. 49. 3. Which picture shows how objects stick to bar magnets?
  48. 50. <ul><li>4. What colour would a South Pole be on a magnet? </li></ul>a) Red b) Green c) Grey d) Blue
  49. 51. <ul><li>5. What is another word for &quot;not sticking&quot;? </li></ul>a) Avoid ing b) Attract ing c) Repel ling d) Running away
  50. 52. Interesting links <ul><li> </li></ul><ul><li>http:// /modules/ groups / homepagefiles / cms /14571/File/ Magnets%20Webquest / Magnets_Webquest.html </li></ul><ul><li> </li></ul><ul><li> </li></ul>
  51. 53. <ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul>
  52. 54. Bibliography <ul><li>Book: What Makes A Magnet Author: Franklyn M. Branley Illustrator: True Kelley Publisher: HarperCollins Publication Date: July 1996 Pages: 32 Pages Grade Range: Kindergarten, First Grade and Second Grade ISBN: 978-0060264413 </li></ul>