interesting fact about magnets

WHAT MAKES A MATERIAL MAGNETIC?

Electricity and magnetism are linked. As positively or negatively charged particles move, they generate a magnetic field that circles around the direction of the current. This happens when charged metal ions swirl around in the Earth’s core, charged particles zip through the interior of the Sun and electrons race along an electrical wire. Magnetic fields affect other charged particles that attempt to travel through, forcing them to change the direction they are travelling in. This also happens at the subatomic scale. We know that magnetic fields are generated when charged particles move, but they don’t have to be travelling along an electrical wire, even tiny movements are enough. Every electron in every atom is spinning on its own axis, and because of its negative charge, this movement generates a ‘magnetic moment’. Each electron is essentially a tiny magnet .In most materials, the electrons are in pairs – one spinning ‘up’ and one spinning ‘down’ – so their magnetic moments cancel each other out. However, in other materials there are electrons without a partner. If enough of these unpaired electrons are spinning in the same direction, the combined effect of their individual magnetic moments generates an external magnetic field. Even if the electrons aren’t all spinning in the same direction, the fact that they are without a partner has important effects on the behavior of the material. Depending on their structure, materials respond differently to magnets. If all of the electrons are paired, materials are diamagnetic – they are not attracted to magnetic fields. In fact, they weakly repel them. This applies to most of the elements, including metals like gold and silver, and non-metals like wood or petroleum. If a few of the electrons are unpaired, materials are paramagnetic – they are ever so slightly attracted to magnetic fields. Two examples include magnesium and oxygen. Finally, if there are lots of unpaired electrons, materials are ferromagnetic – strongly attracted to magnetic fields and able to make magnets. The key ferromagnetic elements are iron, nickel and cobalt.

WHY IS MAGNET SO MPORTANT?

Electromagnets are responsible for generating the vast majority of our electricity. From coal and oil, to wind and waves, most of our power stations generate a current using the same basic principles. Something (steam, water, and wind) spins a turbine, which is linked to a generator by an axle. As the axle turns, it spins a coil of metal inside magnetic field (or vice versa) and produces a current. Converting the electrical energy back into mechanical energy also uses magnets – the process is simply reversed .Magnets in electric motors turn car wheels, washing machine drums, fridge compressors, electric drills and many more. Magnets are used to produce the vibrations needed to transmit sound from a headphone or speaker. They also encode data on the magnetic strips of credit cards and hold Information stored on hard drives. They are used by scientists to study the universe, bending the path of particles at facilities like CERN, and they are used in the lab to investigate chemical structures via nuclear magnetic resonance (NMR) imaging. In hospitals, this same technology enables doctors to look inside the human body without the need for surgery. Our world today would be unrecognizable without magnets!

Why do magnets disrupt screens?

Cathode ray tube (CRT) television screens and computer monitors are very sensitive to the effects of magnets. This is because the image is produced by a stream of charged electrons.

Inside the screen is a cathode ray tube – a vacuum tube containing a heated filament that produces a steady supply of electrons. These hurtle towards the screen, where they collide with chemicals known as phosphors, changing their color. Holding a magnet to the screen bends the path of the electrons, warping the image.

What is magnetic sand?

Magnetics and, also known as black sand, is made from tiny grains of the iron oxide, magnetite. It is much heavier than normal Silicone-based sand, so patches of magnetic sand can sometimes be found where other grains have been swept away by the wind.

 

Are any liquids magnetic?

Yes, ferrofluids are liquids containing tiny suspended particles of magnetic materials – usually cobalt or iron. The particles are kept separate using chemicals known as surfactants similar to washing up liquid). If you put a magnet close to some ferrofluids, it will pull the liquid into spikes along the field lines.

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