Scientific Sunday#6- Magnetism

Magnetism

I am sure everyone of you who are reading this blog post has seen a magnet before. A special stone that attracts metals to it. You can find it at your everyday tools like screw driver, compasses and refrigerator doors. But have you ever wonder what is it made out of and why it attracts metals. A magnet is made out of  material that can be magnetized, mostly nickel, iron, cobalt and some rare material. They are so called ferromagnetic. 

Earth's magnet

A magnet's power to attract or repel is all in its atom. Electrons and protons are laways in motion. Because any moving charge generates a magnetic field, each of those particles has one. Usually the fields are haphazard, but in materials such as iron, they tend to line up within specific regions called domains. When ferrous, or iron- containing rock is molten, all the domains align with Earth's own magnetic field. Thats how natural magnets are formed.

Today we do have harnessed magnet in our everyday lives. They reside in television screens- including CRT( cathode ray tube), LCD( liquid crystal display), LED( light-emitting diode), and plasma screens. Magnetic resonance imagining(MRI) allows us to make medical dianoses that were previously unimaginable. Electromagnetism has improved our transportation system in the form of maglev( magnetic levitation) trains. Magnets intergal to electric motors enable such tools as power drills, garbage disposals, and electric razors. 

Magnetic fields have two polarities- usually called north and south- that attract each other but repel its own. Depending on how the charged particles( electrons and protons) are aligned in the magnet. Humans have known about this force for a long time- as far back as the ancient Greek. Columbus used a magnetic compass in 1492 on his famous voyage to seek trade route to India, and in 1600, William Gilbert, physician to Queen Elizabeth 1 of England, tool the idea further by proposing that Earth itself was a giant magnet. Which he was right about.

Compass

Compass expended our ability to navigate and explore our world without losing our sense of direction. Before the invention of compass, voyagers used stars and coastal landmarks to navigate their voyage. Ancient Chinese were the first to discover water-based compasses: Magnetic needle floating in bowls of water. The needles were magnetized by stroking them with a lodestone, a naturally magnetized piece of mineral magnetite(iron oxide). Originally, the needles were used in fortune telling before being put to a more practical use. 

A compass works by sensing the magnetic field that is produced by Earth's core, which contains iron. The magnetic field is weak at the surface, which makes sense given that it's spread out across the entire planet. For the magnetic field to have any effect on the compass at all, the needle must be light and have an almost frictionless bearing. 

Creature like cows, birds, and bacteria apparently carry compasses around with them: They all have an unerring sense of where true north lies. How they manage this remains a mystery, but a recent study of a curtain kind of bacteria offers a clue. Researchers discovered that these organisims have minute particles of magnetite inside them. The particles line up with Earth's magnetic field. Scientist have found similar magnetic particles near the brains of bees, trout, and migrating birds.

Thanks for reading