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Magnets

Magnets. What is a magnet?. A magnet is an object that has the property of attracting certain materials, mainly iron and steel. North and South. Every magnet has a North Pole and a South Pole . Opposite poles attract (come together) each other.

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Magnets

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  1. Magnets

  2. What is a magnet? • A magnet is an object that has the property of attracting certain materials, mainly iron and steel.

  3. Northand South • Every magnet has a North Pole and a South Pole. • Opposite poles attract (come together) each other. • Like poles repel (move away from) each other. • Attract - the act of trying to come together.

  4. Natural Magnets • A natural magnet is an object which has a magnetic field around it. An example of a natural magnet is Magnetite.

  5. Magnetite • The most popular legend accounting for the discovery of magnets is that of an elderly Cretan shepherd named Magnes. Legend has it that Magnes was herding his sheep in an area of Northern Greece called Magnesia, about 4,000 years ago. Suddenly both, the nails in his shoes and the metal tip of his staff became firmly stuck to the large, black rock on which he was standing. To find the source of attraction he dug up the Earth to find lodestones (load = lead or attract). Lodestones contain magnetite, a natural magnetic material Fe3O4. This type of rock was subsequently named magnetite, after either Magnesia or Magnes himself. • Lodestones were used to tell direction. http://www.howmagnetswork.com/history.html

  6. Permanent Magnets • A permanent magnet is a man-made object with a magnetic field around it. It has parts that are usually labeled as North and South. It will keep its magnetism for a long period of time. • A permanent magnet can be demagnetized by heat, hammering and by other magnets. http://www.coolmagnetman.com/images/alnico2.jpg

  7. Temporary Magnets • A Temporary Magnet is an object which has a magnetic field around it for a short period of time. An example of a temporary magnet is an electromagnet.

  8. imanes

  9. Imán natural piedra imán

  10. Ejemplos de imanes naturales magnetita

  11. Imán permanente

  12. Ejemplos de imanes permanetes herradura barra redondo

  13. Imán temporal

  14. Ejemplos de imanes temporales • electroiman

  15. polo • Polo: zona de un imán donde el campo magnético tiene más fuerza • Los imanes tienen un polo norte y un polo sur. norte sur

  16. repeler • Repeler- apartar de sí • Los polos iguales se repelen.

  17. atraer • Atraer- traer hacia sí (jalar) • Los polos opuestos se atraen.

  18. Electromagnet • A temporary magnet made by passing an electric current through a wire coiled around an iron bar.

  19. Electromagnet • A junkyard is one place to see an electromagnet in action. A crane holding a huge electromagnet can be used to pick up scrap metal when current flows through it. When the crane operator wants to drop the scrap, he or she will simply shut off the current to the electromagnet. http://www.bbc.co.uk/schools/ks3bitesize/science/physics/magnetism_5.shtml

  20. Magnets have a magnetic field. • A magnetic field is the area around a magnet where you can detect the force of the magnet. www.school-for-champions.com/science/images/magnetic_detection-iron_filings.jpg

  21. Magnetic Field • The magnetic field is always strongest near the poles! • If you cut a magnet in half you will have two new magnets. They will both have a North and a South pole. http://www.how-things-work-science-projects.com/second-grade-science-projects.html

  22. Magnetic Force • The power of a magnet to push or pull other magnetic material. • The strength of the magnetic field is the magnetic force.

  23. Earth’s Magnetic Field • The Earth does not contain a giant bar magnet, but it behaves as if it does. The Earth has a magnetic north pole and a magnetic south pole. http://www.bbc.co.uk/schools/ks3bitesize/science/physics/magnetism_5.shtml

  24. We use Earth’s magnetic field to figure out where we are.

  25. Compass • A compass is an object with a small magnetic section that detects the north pole of Earth and points to it. • the north pole of a bar magnet is actually called the 'north-seeking pole', and it points to the Earth's magnetic north pole; • the south pole of a bar magnet is actually called the 'south-seeking pole', and it points to the Earth's magnetic south pole.

  26. Where am I? • The south pole of a magnet is attracted to the Magnetic North Pole of the Earth. The south pole of a bar magnet is labeled "N." This can be confusing. • A famous aviator nicknamed "Wrong Way Corrigan" flew from New York to Ireland when he was supposed to be going to Kansas. He claimed he followed the wrong end of his compass.

  27. Magnets are everywhere, can you think of where?

  28. Magnetismo • Magnetismo es lafuerza de atracción o de repulsión de un imán

  29. Electroiman • Imanes temporarios creados al pasar una corriente eléctrica a través de un alambre enroscado alrededor de una pieza de hierro

  30. Campo magnético • campo magnético es el espacio alrededor de un imán dentro del cual el imán puede atraer objetos

  31. La tierra tiene un campo magnetico.

  32. Campo magnético fuerte • La tierra tiene un campo magnético fuerte.

  33. Campo magnético débil • Un imán pequeño tiene un campo magnético débil.

  34. Campo magnético fuerte Campo magnético debil.

  35. La brújula • Usamos el campo magnetico para nevegar.

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