Blog Categories

About Us has become the premier magnetic bracelet, copper bracelet and magnetic jewelry online catalog as a result of our commitment to one simple tenet - customer service.

Recent Posts

Blog Archive

  1. August 20151 Posts
  2. March 20151 Posts
  3. June 20141 Posts
  4. December 20131 Posts
  5. November 20131 Posts
  6. August 20131 Posts
  7. March 20132 Posts
  8. December 20121 Posts
  9. November 20121 Posts
  10. August 20121 Posts
  11. December 20111 Posts
  12. November 20112 Posts
  13. October 20113 Posts
  14. September 20111 Posts
  15. August 20113 Posts
  16. June 20111 Posts
  17. April 20112 Posts
  18. March 20113 Posts
  19. February 20112 Posts
  20. January 20115 Posts
  21. December 20102 Posts
  22. November 20101 Posts
  23. October 20105 Posts
  24. August 20105 Posts
  25. June 20101 Posts
  26. May 20101 Posts
  27. April 20101 Posts
  28. March 20104 Posts
  29. February 20105 Posts
  30. January 20106 Posts
  31. December 20096 Posts
  32. October 20096 Posts
  33. September 20095 Posts
  34. August 20096 Posts
  35. July 200912 Posts
  36. June 20094 Posts
  37. May 20096 Posts
  38. April 20095 Posts
  39. March 200910 Posts
  40. February 20094 Posts
  41. January 20094 Posts
  42. December 20089 Posts
  43. November 20084 Posts
  44. October 20081 Posts
  45. September 20086 Posts
  46. August 20082 Posts
  47. July 20081 Posts
  48. April 20081 Posts
  49. February 20083 Posts
  50. January 20089 Posts
  51. December 20074 Posts
  52. September 20072 Posts
  53. August 20071 Posts
  54. July 20073 Posts
  55. June 20079 Posts
  56. May 200719 Posts
  57. April 200734 Posts
  58. March 200748 Posts
  59. February 200722 Posts
  60. January 20077 Posts
  61. December 20061 Posts
  62. November 200622 Posts
  63. October 200611 Posts
  64. September 20062 Posts
  65. August 20065 Posts

Apr 17

Living Lodestones

Lemon Shark (Negaprion brevirostris)

Magnets are familiar strangers. Most of us have at least one around the house - in our telephone receivers, stereo and TV speakers, or used to turn our refrigerators into bulletin boards and art galleries. The earliest magnets (circa 500 BC) were naturally-occurring lumps of an iron oxide mineral known as 'magnetite' (Fe3O4) and were imputed with all manner of mystical properties. Today, magnets come in all shapes and sizes: from simple bars and 'classic' horseshoes to various business logos and cartoon characters to food, fishes, cows, and even baby-blue pigs with 'Think Thin' written across their bellies - thereby holding up both our best intentions and our kids' baseball schedules. Magnets are everywhere. But few of us understand how they work.

Magnetism and electricity are fundamentally interconnected. Danish scientist Hans Christian Oersted showed in 1820 that an electric current flowing in a wire deflects a compass nearby. Whenever an electric current flows - whether from cloud to ground in the form of lightning or through a contracting muscle in the body - a magnetic field is created. The unification of electric and magnetic principles under a comprehensive mathematical theory was first achieved by Scottish physicist James Clerk Maxwell in 1864. It is now known that magnetism is a property of the atom itself. Ultimately, the magnetic properties of matter are determined by the collective behavior of the negatively charged electrons that orbit the nuclei of atoms. The magnetic dipole moment (or magnetic field) of an individual electron has two components, one resulting from the spin of the electron about its own axis, the other from its orbital motion about the nucleus. Both kinds of motion may be considered as tiny circular currents (moving charges), thus linking electricity and magnetism at an atomic level.

In most atoms and molecules, these electronic magnets are oriented in random directions and the sum total magnetic moment of all the orbital electrons is zero. However, in some highly ordered crystalline materials - such as iron, nickel, and cobalt - the spins of some orbital electrons in adjacent atoms become coupled (I will spare you the quantum physics), creating local magnetic 'domains' in which magnetization is unidirectional. Adjacent domains are magnetized in different directions, so that there is no bulk magnetization. When an external magnetic field is applied, those domains aligned with the field grow at the expense of others, resulting in a very strong type of permanent magnetization known as 'ferromagnetism'. So from where does this 'external field' come? For the answer, we must look to the Earth's core....Read on...

Posted by Jay Roberts at 10:03 PM | Permalink


TrackBack URL for this entry: