Explain the use of magnetic screening and magnetic keepers.
Describe the uses of magnets.
CONTENT
Magnetism is a force exerted by magnetic objects without touching each other. A magnetic object is surrounded by a magnetic field, a region in space where a magnet or object made of magnetic material will experience a non-contact force. Electrons inside any object have magnetic fields associated with them. The way the electrons' magnetic fields line up with each other explains magnetic fields in ferromagnetic materials (e.g. iron), magnetisation, permanent magnets and polarity of magnets. These concepts are explored with descriptions, diagrams and investigations.
Properties of Magnetism
Magnets have a pair of opposite poles, north and south. Like poles of a magnet repel; unlike poles attract. It is not possible to isolate north and south poles - even if you split a magnet, you only produce two new magnets. The magnetic field line around a bar magnet can be visualised using iron filing s and compass needles. Learners need to be reminded that the field is three dimensional, although illustrations depict the fields in 2D. To show the shape, size and direction of the magnetic fields different arrangements of bar magnets are investigated and illustrated.
Magnetic Fields
The pattern of the Earth’s magnetic field is as if there is an imaginary bar magnet inside the Earth. Since a magnetic compass needle (a north pole) is attracted to the south pole of a magnet, and magnetic field lines always point out from north to south, the earth’s pole which is geographically North is magnetically actually a south pole. The Earth has two north poles and two south poles: geographic poles and magnetic poles.
The geographic North Pole, which is the point through which the earth's rotation axis goes, is about 11,5 away from the direction of the Magnetic North Pole (which is where a compass will point). Learners are made aware of the importance of the earth's magnetic field acting as a shield to stop electrically charged particles emitted by the sun from hitting the earth and us. Charged particles can damage and cause interference with telecommunications (such as cell phones).
Geographic North Pole
Solar wind is the stream of charged particles (mainly protons and electrons) coming from the sun. These particles spiral in the earth's magnetic field towards the poles. If they collide with particles in the earth's atmosphere they sometimes cause red or green lights, or a glow in the sky which is called the aurora, seen at the north and south pole.
" />Phenomena of Magnetism
Specific outcomes
Describe properties of magnets
Distinguish the magnetic properties of iron and steel.
Explain the use of magnetic screening and magnetic keepers.
Describe the uses of magnets.
CONTENT
Magnetism is a force exerted by magnetic objects without touching each other. A magnetic object is surrounded by a magnetic field, a region in space where a magnet or object made of magnetic material will experience a non-contact force. Electrons inside any object have magnetic fields associated with them. The way the electrons' magnetic fields line up with each other explains magnetic fields in ferromagnetic materials (e.g. iron), magnetisation, permanent magnets and polarity of magnets. These concepts are explored with descriptions, diagrams and investigations.
Properties of Magnetism
Magnets have a pair of opposite poles, north and south. Like poles of a magnet repel; unlike poles attract. It is not possible to isolate north and south poles - even if you split a magnet, you only produce two new magnets. The magnetic field line around a bar magnet can be visualised using iron filing s and compass needles. Learners need to be reminded that the field is three dimensional, although illustrations depict the fields in 2D. To show the shape, size and direction of the magnetic fields different arrangements of bar magnets are investigated and illustrated.
Magnetic Fields
The pattern of the Earth’s magnetic field is as if there is an imaginary bar magnet inside the Earth. Since a magnetic compass needle (a north pole) is attracted to the south pole of a magnet, and magnetic field lines always point out from north to south, the earth’s pole which is geographically North is magnetically actually a south pole. The Earth has two north poles and two south poles: geographic poles and magnetic poles.
The geographic North Pole, which is the point through which the earth's rotation axis goes, is about 11,5 away from the direction of the Magnetic North Pole (which is where a compass will point). Learners are made aware of the importance of the earth's magnetic field acting as a shield to stop electrically charged particles emitted by the sun from hitting the earth and us. Charged particles can damage and cause interference with telecommunications (such as cell phones).
Geographic North Pole
Solar wind is the stream of charged particles (mainly protons and electrons) coming from the sun. These particles spiral in the earth's magnetic field towards the poles. If they collide with particles in the earth's atmosphere they sometimes cause red or green lights, or a glow in the sky which is called the aurora, seen at the north and south pole.
">Phenomena of Magnetism
Specific outcomes
Describe properties of magnets
Distinguish the magnetic properties of iron and steel.
Explain the use of magnetic screening and magnetic keepers.
Describe the uses of magnets.
CONTENT
Magnetism is a force exerted by magnetic objects without touching each other. A magnetic object is surrounded by a magnetic field, a region in space where a magnet or object made of magnetic material will experience a non-contact force. Electrons inside any object have magnetic fields associated with them. The way the electrons' magnetic fields line up with each other explains magnetic fields in ferromagnetic materials (e.g. iron), magnetisation, permanent magnets and polarity of magnets. These concepts are explored with descriptions, diagrams and investigations.
Properties of Magnetism
Magnets have a pair of opposite poles, north and south. Like poles of a magnet repel; unlike poles attract. It is not possible to isolate north and south poles - even if you split a magnet, you only produce two new magnets. The magnetic field line around a bar magnet can be visualised using iron filing s and compass needles. Learners need to be reminded that the field is three dimensional, although illustrations depict the fields in 2D. To show the shape, size and direction of the magnetic fields different arrangements of bar magnets are investigated and illustrated.
Magnetic Fields
The pattern of the Earth’s magnetic field is as if there is an imaginary bar magnet inside the Earth. Since a magnetic compass needle (a north pole) is attracted to the south pole of a magnet, and magnetic field lines always point out from north to south, the earth’s pole which is geographically North is magnetically actually a south pole. The Earth has two north poles and two south poles: geographic poles and magnetic poles.
The geographic North Pole, which is the point through which the earth's rotation axis goes, is about 11,5 away from the direction of the Magnetic North Pole (which is where a compass will point). Learners are made aware of the importance of the earth's magnetic field acting as a shield to stop electrically charged particles emitted by the sun from hitting the earth and us. Charged particles can damage and cause interference with telecommunications (such as cell phones).
Geographic North Pole
Solar wind is the stream of charged particles (mainly protons and electrons) coming from the sun. These particles spiral in the earth's magnetic field towards the poles. If they collide with particles in the earth's atmosphere they sometimes cause red or green lights, or a glow in the sky which is called the aurora, seen at the north and south pole.
Explain the use of magnetic screening and magnetic keepers.
Describe the uses of magnets.
CONTENT
Magnetism is a forceIn physics, a force is any influence that causes a free body... More exerted by magnetic objects without touching each other. A magnetic object is surrounded by a magnetic field, a region in space where a magnet or object made of magnetic materialMaterial or Matter is anything which has mass and occupies s... More will experience a non-contact forceIn physics, a force is any influence that causes a free body... More. Electrons inside any object have magnetic fields associated with them. The way the electrons’ magnetic fields line up with each other explains magnetic fields in ferromagnetic materials (e.g. iron), magnetisation, permanent magnets and polarity of magnets. These concepts are explored with descriptions, diagrams and investigations.
Properties of Magnetism
Magnets have a pair of opposite poles, north and south. Like poles of a magnet repel; unlike poles attract. It is not possible to isolate north and south poles – even if you split a magnet, you only produce two new magnets. The magnetic field line around a bar magnet can be visualised using iron filing s and compass needles. Learners need to be reminded that the field is three dimensional, although illustrations depict the fields in 2D. To show the shape, size and direction of the magnetic fields different arrangements of bar magnets are investigated and illustrated.
Magnetic Fields
The pattern of the Earth’s magnetic field is as if there is an imaginary bar magnet inside the Earth. Since a magnetic compass needle (a north pole) is attracted to the south pole of a magnet, and magnetic field lines always point out from north to south, the earth’s pole which is geographically North is magnetically actually a south pole. The Earth has two north poles and two south poles: geographic poles and magnetic poles.
The geographic North Pole, which is the point through which the earth’s rotation axis goes, is about 11,5 away from the direction of the Magnetic North Pole (which is where a compass will point). Learners are made aware of the importance of the earth’s magnetic field acting as a shield to stop electrically charged particles emitted by the sun from hitting the earth and us. Charged particles can damage and cause interference with telecommunications (such as cell phones).
Geographic North Pole
Solar wind is the stream of charged particles (mainly protons and electrons) coming from the sun. These particles spiral in the earth’s magnetic field towards the poles. If they collide with particles in the earth’s atmosphere they sometimes cause red or green lights, or a glow in the sky which is called the aurora, seen at the north and south pole.
Distinguish the magnetic properties of iron and steel.
Explain the use of magnetic screening and magnetic keepers.
Describe the uses of magnets.
Course Content
PROPERTIES OF MAGNETS
oCertain materials are capable of exerting magnetic forces and are called magnet. The forces are concentrated at opposite ends of a magnet, in areas called poles.
oThere are two characteristic poles of magnetic force, called north-seeking (north pole) and south-seeking (south pole). The fundamental law of magnetic poles states that, “similar poles repel, opposite poles attract”.
oThe region of magnetic force around magnet is called a magnetic field and is represented by magnetic field lines that show the direction of the force on the N-pole of a small test compass at each point in the field.
oSubstances containing iron, nickel, or cobalt may be induced to become magnets by being placed in a magnetic field. They are called ferromagnetic materials.
Properties of Magnets
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MAGNETISATION AND DEMAGNETISATION
oThe ferromagnetic materials can be magnetised through induction, hammering, stroking and electric method
oThe magnets can be demagnetised through heating hammering while placed in East –West direction and electric method while withdrawn in East-west direction from a solenoid with an alternating current passing through it.
oInduced magnetism may be explained by means of the theory of domains. Ferromagnetic materials are composed of a large number of tiny magnetic dipoles. Groups of aligned dipoles form magnetic domains that are normally oriented at random. In the presence of a magnetic field, the dipoles turn so that most domains are aligned in the same direction to form a magnet.
oThe domain theory may be used to explain:
(i)Magnetic induction
(ii)Demagnetisation of temporary magnet
(iii)Reverse magnetisation of a bar magnet
(iv)The breaking of a bar magnet into a large number of smaller magnets
(v)Magnetic saturation
(vi)Magnetism induced by the earth
(vii)Keepers for bar magnets
oKeepers are soft iron bars placed in such a way that they join the two pole of U or C-shaped magnet or a pair of two bar magnets to prevent them from losing magnetism through the reverse in direction on the alignment of the domains over time.
