THE EARTH HAS A HUGE magnetic field and all magnetic objects ,such as compass needle ,get oriented to it.One end of the freely rotating compass needle marked in color aligns itself with the North pole of the Earth .This helped the early explorers to find their ways in oceans .Near the poles they often saw an impressive phenomenon in the sky known as aurora .Moreover ,a lot of things would not have existed today without strong magnets called electromagnets that can be switched on and off.
MAGNET ATTRACTS IRON. -Magnets are made up of many tiny magnets ,which are groups of iron atoms.
Although these iron atoms are also present in non metallic metals ,they are completely disorganized there.In contrast ,in a permanent magnet ,iron atoms are aligned in a uniform way..All the south poles points to one end and all the north pole to the other end .Thus a magnet has a strong north pole and a strong south pole.If a piece of iron comes near a magnet , the atom in it get aligned .The piece of iron become magnetized for short time and is attracted to one of the poles of the magnet.On removing the ,the alignment of the atoms get disorganized again.In permanent magnets , atoms retains their alignment .
STRENGTH OF MAGNETS.-DEPENDING on the strength of the magnet ,it attracts metallic pieces from different distances .Materials lying between the magnets and the metal affects its strength .A concrete slab interrupts the magnetic field of the magnet,whereas paper and skin do not .The magnetic field is made visible by laying a glass plate on the magnet and scattering fine fine iron chips on it..The chips get aligned along the field lines, which run outside the magnet from the north pole to the south pole.
CAUSE OF THE EARTH'S MAGNETIC FIELD-IN the Earth's core a viscous mass containing iron moves around a solid iron core .According to scientists , the flow of iron acts like an electrical coil and is the cause of the Earth's magnetic field .Like any other magnet ,the Earth has a north pole and a south pole.These poles lies some thousands of kilometer away from the geographical poles .Not only sailors and pilots but also many migratory birds , dolphins, and salmons orient themselves to the magnetic field of the Earth.Small crystals of magnetite in their heads , acting like tiny compass needles , impart them a 'magnetic sense '.
ELECTROMAGNET S- ELECTRIC current generate a magnetic field .A Danish scientist Hans Oersted , while doing an experiment ,observed that , a magnetic needle lying on the side got deflected when he switched on the current .The needle went back to its original position when the current was witched off.This discovery allowed us to make electromagnets .An electromagnet is an insulated wire wound around a piece of iron . The current flowing through the 'coil' generate a magnetic field that magnetizes the iron in the coil.The stronger the current , the stronger the electromagnet.
AURORA- These are polar lights ,are bright bands of light that streak in the sky of polar regions. The sun emits high -energy iron particles .These electrically charged particles , also known as solar winds , get deflected by the earth's magnetic field .As a result they are drawn magnetically down into the ionosphere above the earth's surface at the poles.Their collision with the gas particles of the air causes the impressive display of colors in the northern sky.The magnetic field of the Earth ,protects us from the Solar winds , which would otherwise destroy all life on the Earth.
MAGNET ATTRACTS IRON. -Magnets are made up of many tiny magnets ,which are groups of iron atoms.
Although these iron atoms are also present in non metallic metals ,they are completely disorganized there.In contrast ,in a permanent magnet ,iron atoms are aligned in a uniform way..All the south poles points to one end and all the north pole to the other end .Thus a magnet has a strong north pole and a strong south pole.If a piece of iron comes near a magnet , the atom in it get aligned .The piece of iron become magnetized for short time and is attracted to one of the poles of the magnet.On removing the ,the alignment of the atoms get disorganized again.In permanent magnets , atoms retains their alignment .
STRENGTH OF MAGNETS.-DEPENDING on the strength of the magnet ,it attracts metallic pieces from different distances .Materials lying between the magnets and the metal affects its strength .A concrete slab interrupts the magnetic field of the magnet,whereas paper and skin do not .The magnetic field is made visible by laying a glass plate on the magnet and scattering fine fine iron chips on it..The chips get aligned along the field lines, which run outside the magnet from the north pole to the south pole.
CAUSE OF THE EARTH'S MAGNETIC FIELD-IN the Earth's core a viscous mass containing iron moves around a solid iron core .According to scientists , the flow of iron acts like an electrical coil and is the cause of the Earth's magnetic field .Like any other magnet ,the Earth has a north pole and a south pole.These poles lies some thousands of kilometer away from the geographical poles .Not only sailors and pilots but also many migratory birds , dolphins, and salmons orient themselves to the magnetic field of the Earth.Small crystals of magnetite in their heads , acting like tiny compass needles , impart them a 'magnetic sense '.
ELECTROMAGNET S- ELECTRIC current generate a magnetic field .A Danish scientist Hans Oersted , while doing an experiment ,observed that , a magnetic needle lying on the side got deflected when he switched on the current .The needle went back to its original position when the current was witched off.This discovery allowed us to make electromagnets .An electromagnet is an insulated wire wound around a piece of iron . The current flowing through the 'coil' generate a magnetic field that magnetizes the iron in the coil.The stronger the current , the stronger the electromagnet.
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