What is Magnetism?
Properties of Magnets:
Magnet: any material that attracts iron and materials that contain iron Magnets attract iron and materials that contain iron. magnets attract or repel other magnets. In addition, one part of a magnet will always point north when allowed to swing freely. Magnetic Poles:
Magnetic Pole: any magnet with 2 ends, each is called a magnetic pole. Magnetic poles that are unlike attract each other and magnetic poles that are alike repel each other. Magnetic Force: the attraction or repulsion between magnetic poles Magnetic Fields:
Magnetic Field: the area of magnetic force around a magnet
Magnetic Field Lines: invisible lines that map out the magnetic field around a magnet. Magnetic field lines spread out from one pole, curve around the magnet, and return to the other pole. Inside Magnetism
Atom: the smallest particle of an element
Element: basic substances that make up all matter.
Nucleus: center region of the atom
Protons: particle that is positive
Neutron: Particle that has no charge
Electron: particle that is negative
A spinning electron produces a magnetic field that makes the electron behave like a tiny magnet in an atom. Magnetic Domains:
Magnetic Domain: grouping of atoms that have their magnetic feilds aligned In a magnetized material, all or most of the magnetic domains are arranged in the same direction. Ferromagnetic Material: A material that shows strong magnetic properties.
Making and Changing Magnets
Magnets can be made, destroyed or broken apart.
Temporary Magnet: magnet made from a material that easily loses its magnetism Permanent Magnet: Magnet made from a material that keeps its magnetism for a long time Magnetic Earth:
Compass: a device that has magnetized needle that spins freely Earth as a Magnet:
Just like a bar magnet, Earth has a magnetic field surrounding it 2 magnetic poles Magnetic Declination: the angle (at a particular location) between magnetic north and true north Earth’s Magnetic Field:
Since Earth produces a strong magnetic field, Earth itself can make magnets out of ferromagnetic materials. The Magnetosphere
Earth’s magnetic field affects the movements of electrically charged particles in space. Van Allen belts: between 1,000-25,000 km above Earth’s surface are 2 doughnut-shaped regions Solar Wind: stream of electrically charged particles flowing at high speeds from the sun Magnetosphere: Earth’s magnetic field shaped by the solar wind Aurora: glowing region in the atmosphere caused by charged particles from the sun
Charges that are the same repel each other.
Charges that are different attract each other.
Electric Force: attraction or repulsion between electric charges Electric Field: extends around a charged object
An electric field is a region around a charged object where the object’s electric force is exerted on other charged objects.
Static Electricity: the buildup of charge on an object
In static electricity, charges build up on an object, but they do not flow continuously.
Law of Conservation of Charge: charges are neither created nor destroyed There are three methods by which charges can be transferred to build up static electricity: charging by friction, by conduction, and by induction. Charging by friction: the transfer of electrons from one uncharged object to another by rubbing Charging by conduction: the transfer of electrons from a charged object to another object by direct contact Charging by induction: the movement of electrons to one part of an object that is caused by the electric field of a second object
When a negatively charged object and a positively charged object are brought together, electrons transfer until both objects have the same charge. Static Discharge: the loss of static electricity as electric charges transfer from one object to another
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