Shared magnets lose their magnetism

mint

magnetism

 

 

 

 

 

 

 

 

 

 

Magnetization and demagnetization

 

 

 

 

 

 

 

 

 

 

The magnetic poles

 

 

 

 

 

 

 

 

 

Magnetic effects and fields

 

 

 

 

 

 

 

 

Earth magnetism and compass

 

 

 

 

 

 

use

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

handling and storage

 

 

 

 

 

 

Magnet applications in everyday life

 

The stones that could attract small pieces of iron were already known in ancient times. They were probably named after the Greek landscape Magnesia, where a lot of magnetic iron ore was found.

As magnetism describes the ability to attract objects made of iron, nickel or cobalt. It can be found predominantly in ferromagnetic materials.

That is why permanent magnets are made from iron, steel and various alloys, which are magnetized with a coil carrying direct current.


But magnetism can also be produced differently: If you stroke a piece of steel several times with the same pole in the same direction with a magnet, the steel becomes magnetized.


Magnets lose their attraction due to heating or strong vibrations (demagnetization).

Magnetization and demagnetization can be explained with the help of a model:

One imagines that ferromagnetic bodies (e.g. a nail) are composed of a large number of small "elementary magnets". They are mixed up so that their forces cancel each other out.

When magnetized, all the small magnets face the same direction Now their powers are strengthening. The nail becomes magnetic.

That's why a split magnet still works 2 poles has and is magnetic.

Magnetism arises from that same direction of rotation (spin) atomic particles. Ultimately, however, there is still a need for research into how the forces arise and are transferred.

Magnets are not equally strong over their entire surface. The two places where the magnet is strongest are called North and South Pole. If magnets meet, the same poles repel each other, different ones attract each other.

 

Pole of the same name
(North Pole + North Pole or South Pole + South Pole)
repel each other,
Poles of a different name
(North Pole + South Pole or South Pole + North Pole)
get dressed.

A magnet doesn't just attract contact on - like glue - but it also acts over Distances. This space of attraction around the magnet is called his "magnetic field". With the help of iron filings you canField lines"Make your space visible. Depending on the nature of the magnet, the magnetic field varies in size. (Children speak of strong and weak magnets.) The magnetic force can work through gases, liquids and solid bodies. Attached iron parts give the." Forces on.
The so-called Permanent magnets generate a permanent magnetic field. Using a wire wound around an iron core (a Kitchen sink) a magnetic field can also be generated when a current is supplied. But it doesn't last. As soon as the current is switched off, the magnetic field also collapses.

Freely movable magnets always align themselves to the earth's magnetic field in a north-south direction. People take advantage of this behavior when using the Compasses. Compasses are built very differently. Simple devices, however, still consist of a freely movable, magnetized needle over a compass rose. The North Pole of the Nadel is generally marked in blue or red.
Not only humans, but also many animals such as migratory birds use the terrestrial magnetic field for orientation. The exact mechanisms of their "magnetic sense" are the subject of constant research.

As The cause of the earth's magnetisms is believed to be subterranean currents of molten metals. These movements create an electromagnetic field. Mighty eddies in the currents may explain why the poles shift slightly from year to year. The Earth's magnetic poles also do not exactly coincide with their geographic poles. Therefore the setting of the magnetic needle deviates from the exact north-south direction.

Usually magnets are called Stick, horseshoe or discs poured. But other forms are also possible. In order to make the poles recognizable for school experiments, they are often marked in color (North Pole red, South Pole blue or green)

 

 

 

 

 

 

 

 

 

Magnets can be found in practically every household: They are used as cupboard latches, fridge magnets, soap holders, etc. Children's toys contain magnets and the magnetic board has become an indispensable part of school.


Electromagnets are used in technical areas Sorting of substances (e.g. waste recycling) or as Mode of Transport used for objects (e.g. as a scrap crane). The Transrapid hovers very close above magnetic rails at up to 300 km / h. In practically every electric motor, magnetic forces are used for propulsion.

In technical applications, these forces are with Do the washing up generated that allow a more flexible use than permanent magnets. Unfortunately, one has to say goodbye to the idea of ​​being able to use permanent magnets as cheap energy carriers for a "perpetual motion machine" - as with Jim Knopf.

In the Handling and storage of magnets iPlease note the following:

  • Do not drop or hit magnets.
  • Store magnets separately from other ferrous experimental materials.
  • It is best to store magnets with opposite poles next to each other.
  • Do not touch watches, floppy disks or hard drives with magnets

The following is a list of devices and machines that use magnets or electromagnets. The list represents a first selection. The children will not know and name all things. But it proves how important the magnetic force is in our technical world.

  • Computer: floppy disk recording and reading heads, loudspeakers, monitor deflection coil
  • Shower curtain weights
  • TV: deflection coil
  • headphone
  • Credit card: magnetic strip
  • Fridge: door seal
  • Fridge magnets
  • speaker
  • microwave
  • Toys: magnetic arrows, fishing games, ...
  • Dishwasher: water valve
  • phone
  • Cassette and video tapes
  • Cassette and video recorders (tape heads)
  • door bell
  • Alarm clock

Especially in engines (starter relays, clock generators, sensors) for:

  • Car: Electric door locks, electric window motor, indoor fan motor, mirror, adjuster motor, starter motor, wiper motor
  • Cassette recorder
  • CD player, recorder: drive, head support motor
  • Computers: hard drives, floppy disks, CD, DVD drives / burners
  • tin opener
  • Extractor hood
  • DVD player, recorder: drive, head support motor
  • Electric toothbrush
  • Garage door opener
  • fan
  • Oven
  • compressor
  • fridge
  • microwave
  • pump
  • Whisk
  • dishwasher
  • timer
  • tape
  • dryer
  • Fans
  • Video recorder
  • Washing machine