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Chapter 16 – Magnets SPI 0807.12.1 - Recognize that electricity can be produced using a magnet and wire coil. SPI 0807.12.2 - Describe the basic principles of an electromagnet. SPI 0807.12.3 - Distinguish among the Earth’s magnetic field, a magnet, and the fields that surround a magnet and an electromagnet. Section 1: Properties _________ __________ are points on a magnet that have ____________ magnetic qualities. The pole of a magnet that points to the north is called the magnet’s ____________ _______. The opposite end of the magnet, called the _________ ________, points to the south. When you bring two magnets close together, the magnets each exert a magnetic __________ on the other. These magnetic forces result from spinning electric charges in the magnets. The force can either ____ the magnets apart of ____ them together. If you hold the _______ poles of two magnets close together, the magnetic force will ______ the magnets part. The same is true if you hold the south poles close together. If you hold the ________ pole of one magnet close to the ________ pole of another magnet, the magnetic force will ______ the magnets together. A ___________ _________ exists in the region around a magnet in which magnetic forces can act. Why are some materials magnetic and some not? In materials such as iron, nickel, and cobalt, groups of atoms are in tiny areas called ____________. The north and south poles of the atoms in a domain line up and make a _________ magnetic field. If the domains in an object are ______________ arranged, the magnetic fields of the individual domains ___________ each other out, and the object has ____ magnetic properties. If most of the domains in the object are __________, the magnetic fields of the individual domains ____________ to make the __________ object magnetic. Losing Alignment - When domains move, the magnet is _______________________, or loses its magnetic properties. Making Magnets - You can make a magnet from demagnetized material if you _____ ____ its domains with another magnet. When you ___ a magnet in half, you end up with __ magnets. Name four kinds of magnets: Some magnets, called __________________________, are made of iron, nickel, cobalt, or mixtures of those metals. Another kind of magnet is the ________________________. This is a magnet made by an electric current. _________________ magnets are made from materials that are easy to magnetize. But they tend to lose their magnetization easily. _______________ magnets are difficult to magnetize, but tend to keep their magnetic properties longer. Name 2 examples of the effect of Earth’s magnetic field. The Earth behaves as if it has a ________ magnet running through its center. The point of a ___________ needle is attracted to the south pole of a magnet. Opposite poles of magnets attract each other. A compass needle points north because the ____________ ________ of Earth that is closest to the geographic North Pole is a magnetic south pole. Scientists think that the Earth’s magnetic field is made by the movement of electric charges in the Earth’s ________. Earth’s magnetic field plays a part in making __________. An aurora is formed when _____________ particles from the sun hit oxygen and nitrogen atoms in the air. Section 2: _______________________—the interaction between electricity and magnetism. Solenoids and electromagnets. A _____________ is a coil of wire that produces a magnetic field when carrying an electric current. An electromagnet is made up of a solenoid ______________ around an iron core. Electromagnets are very useful because they can be turned _____ and _______ as needed. The solenoid has a field only when there is _________ current in it. Section 3: Michael Faraday conducted an experiment trying to get the magnetic field of the electromagnet to make an electric current in a ____________ wire. Faraday realized that electric current in the _______________ wire was made only when the magnetic field was __________. The process by which an electric current is made by changing a magnetic field is called electromagnetic _________________. The electric current produced by the generator changes direction each time the coil makes a ______ turn. Because the electric current changes direction, it is an __________________ current. The energy that generators convert into electrical energy comes from different sources such as ___________ fuels and _______________energy. A ______________ increases or decreases the voltage of alternating current. The number of ___________ in the primary and secondary coils of a transformer determines whether it increases or decreases the voltage. The electric current that brings electrical energy to your home is usually transformed _____________ times.