Magnetism Notes Know the items Magnetism is the

Magnetism Notes – Know the * items * Magnetism is the force of attraction or repulsion. • A magnet is any object that exhibits the magnetic properties of attraction and repulsion. • Ferromagnetic metals , such as iron, are strongly attracted to magnets and can become magnets. You did this in the warm up activity.

Magnetism Notes • You can make a magnet from something made of iron, cobalt or nickel if you can line up the domains, or clumps of atoms. • Every magnet has two poles—north and south— where the attraction is strongest. * Opposite poles attract; like poles repel.

Magnetism Notes • Earth’s geographic north is its magnetic south pole; its geographic south is its magnetic north. (Also remember the idea from 6 th grade about the magnetic poles flipping many times in history? ) • Every magnet has a magnetic field that runs in a loop from north to south poles, through the magnet, and around. • When like poles are put together, they repel each other as they try to make their field lines line up in the same direction.

Magnetism Notes * Everything is made of atoms, which have a positively charged nucleus and negatively charged electrons orbiting the nucleus. So each atom is a mini-magnet. When electrons move, they create a magnetic field. • In the atoms of most materials, pairs of electrons spin in a way that cancels the magnetic field. • Electrons in magnets spin by themselves, with nothing to cancel the magnetic field.

Magnetism Notes * Magnets stick together because they align their fields to make bigger magnets. • Clumps of magnetic atoms are called domains. *So what makes a material magnetic is the fact that the domains in the object are aligned • Permanent magnets are always attracting and repulsing.

Magnetism Notes – 2 kinds 0 f Magnets

Magnetism Notes – 2 kinds 0 f Magnets * Electromagnetism is the interaction between electricity and magnetism. *An electromagnet is a temporary magnet that becomes a magnet when electricity is applied. • An electric motor uses electromagnets placed around permanent magnets. * The motor converts Electrical energy into mechanical Energy. • An electromagnet can be made stronger by sending my electricity through it or adding more coils to the electromagnet

Magnetism Notes • Magnetism can be used to do things as varied as hold things together, propel vehicles down a track, and produce sounds through audio speakers

MAGNETS Enrichment Activities • http: //www. harcourtschool. com/activity/electromagnets/ • http: //www. harcourtschool. com/activity/science_up_close/504/deploy/int erface. html • Exploratorium • http: //www. exploratorium. edu/snacks/iconmagnetism. html • How Stuff Works: How Electromagnets Work • http: //www. howstuffworks. com/electromagnet. htm • How Stuff Works: How Magnets Work • http: //science. howstuffworks. com/magnet. htm • NOVA: Magnetic Storm • http: //www. pbs. org/wgbh/nova/magnetic/

TEST YOUR KNOWLEDGE OF MAGNETISM 1 A metal that is strongly attracted to a magnet is called ____. 2 Steel is an example of a ferromagnetic material. -------3 Every magnet has ___ where the attraction is strongest. 4 The rule for magnetic poles is : “ like poles ___; opposite poles ___. ” 5 Earth has two magnetic poles. 6 Earth’s geographic north pole is _____. 7 Electrons are tiny _______. 8 In the atoms of most materials, pairs of electrons spin in a way that cancels the magnetic field. 9 A clump of magnetic atoms is called a _____. 10 If you cut a magnet into small pieces, the small pieces are no longer magnetic. 11 This type of magnet is always attracting and repulsing. 12 An electromagnet is a ____ magnet. 13 When electrons move, they create a _____. 14 You can make an electromagnet by coiling a wire around an iron rod. 15 An electromagnet becomes a magnet when electricity is turned on.

TEST YOUR KNOWLEDGE OF MAGNETISM ANSWER KEY 1 A metal that is strongly attracted to a magnet is called ____. Ferromagnetic 2 Steel is an example of a ferromagnetic material. true 3 Every magnet has ___ where the attraction is strongest. two poles 4 The rule for magnetic poles is : “like poles ___; opposite poles ___. ” repel; attract 5 Earth has two magnetic poles. true 6 Earth’s geographic north pole is _____. it’s magnetic south pole 7 Electrons are tiny _____. magnets 8 In the atoms of most materials, pairs of electrons spin in a way that cancels the magnetic field. true 9 A clump of magnetic atoms is called a _____. domain 10 If you cut a magnet into small pieces, the small pieces are no longer magnetic. false 11 This type of magnet is always attracting and repulsing. permanent magnet 12 An electromagnet is a ____ magnet. temporary 13 When electrons move, they create a _____. magnetic field 14 You can make an electromagnet by coiling a wire around an iron rod. true 15 An electromagnet becomes a magnet when electricity is turned on. true