Magnets What is a magnet A magnet is

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. • Like poles repel (move away from) each other. • Attract - the act of trying to come together.

Natural Magnets • A natural magnet is an object which has a magnetic field around it. An example of a natural magnet is 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 Fe 3 O 4. This type of rock was subsequently named magnetite, after either Magnesia or Magnes himself. • Lodestones were used to tell direction. Magnetite http: //www. howmagnetswork. com/history. html

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/alnico 2. jpg

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.

imanes

Imán natural piedra imán

Ejemplos de imanes naturales magnetita

Imán permanente

Ejemplos de imanes permanetes herradura barra redondo

Imán temporal

Ejemplos de imanes temporales • electroiman

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

repeler • Repelerapartar de sí • Los polos iguales se repelen.

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

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

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/ks 3 bitesize/science/physics/magnetism_5. sht ml

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

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-gradescience-projects. html

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

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/ks 3 bitesize/science/physics/magnetism_5. sh tml

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

• 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. Compass

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.

Magnets are everywhere, can you think of where?

Magnetismo • Magnetismo es la fuerza de atracción o de repulsión de un imán

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

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

La tierra tiene un campo magnetico.

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

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

Campo magnético fuerte Campo magnético debil.

La brújula • Usamos el campo magnetico para nevegar.