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Magnets What is a magnet? A magnet is an object that has the property of attracting certain materials, mainly iron and steel. A magnet is an object that.

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Presentation on theme: "Magnets What is a magnet? A magnet is an object that has the property of attracting certain materials, mainly iron and steel. A magnet is an object that."— Presentation transcript:

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2 Magnets

3 What is a magnet? A magnet is an object that has the property of attracting certain materials, mainly iron and steel. A magnet is an object that has the property of attracting certain materials, mainly iron and steel.

4 Property? Properties are the characteristics of an object. A characteristic is the way something is. For example a person’s characteristics could be; She is funny and tall. A characteristic is the way something is. For example a person’s characteristics could be; She is funny and tall. What are the properties of water? What does it feel like? What does it look like? What can it do?

5 Magnets have many properties…. Characteristic All metals are made up of atoms that are usually jumbled around. A metal becomes a magnet when the atoms line themselves up straight. Iron, Nickel and Cobalt (or some mixture that has one of the metals) are the only metals that can be turned into a magnet. Steel has iron in it. All metals are made up of atoms that are usually jumbled around. A metal becomes a magnet when the atoms line themselves up straight. Iron, Nickel and Cobalt (or some mixture that has one of the metals) are the only metals that can be turned into a magnet. Steel has iron in it. What is another word for property? Which metal is a magnet?

6 poles Pole- the area on a magnet where the magnetic force is strongest. All magnets have a north and south pole. Pole- the area on a magnet where the magnetic force is strongest. All magnets have a north and south pole. north south

7 North and South A property of a magnet is that every magnet has a North Pole and a South Pole. Opposite poles attract (come together) each other. Like poles repel (move away from) each other. Attract - the act of trying to come together. A property of a magnet is that every magnet has a North Pole and a South Pole. Opposite poles attract (come together) each other. Like poles repel (move away from) each other. Attract - the act of trying to come together.

8 repel The pushing apart of magnets that occurs when two north ends (or two south ends) of two magnets are brought close to each other.

9 attract The act of trying to come together. Opposite poles are attracted to each other. Example: the north pole of one magnet is attracted to the south pole of another magnet. The act of trying to come together. Opposite poles are attracted to each other. Example: the north pole of one magnet is attracted to the south pole of another magnet.

10 More properties of magnets

11 Magnets have a magnetic field. A magnetic field is the area around a magnet where you can detect the force of the magnet. www.school-for-champions.com/science/images/magnetic_detection-iron_filings.jpg

12 Magnetic Field The magnetic field is always strongest near the poles! If you cut a magnet in half you will have two new magnets. They will both have a North and a South pole. The magnetic field is always strongest near the poles! If you cut a magnet in half you will have two new magnets. They will both have a North and a South pole. http://www.how-things-work-science-projects.com/second-grade- science-projects.html

13 Strong magnetic field The Earth has a very strong magnetic field.

14 Weak magnetic field A bar magnet has a weak magnetic field.

15 Strong magnetic field. Weak magnetic field.

16 Magnetic Force The power of a magnet to push or pull other magnetic material. The strength of the magnetic field is the magnetic force. The power of a magnet to push or pull other magnetic material. The strength of the magnetic field is the magnetic force.

17 Different types of magnets……

18 Natural Magnets A natural magnet is an object fournd in nature which has a magnetic field around it. An example of a natural magnet is the rock Magnetite.

19 Natural Magnet Natural magnet

20 Examples of Natural Magnets magnetite

21 Magnetite The most popular legend accounting for the discovery of magnets is that of an elderly Cretan shepherd named Magnes. Legend has it that Magnes was herding his sheep in an area of Northern Greece called Magnesia, about 4,000 years ago. Suddenly both, the nails in his shoes and the metal tip of his staff became firmly stuck to the large, black rock on which he was standing. To find the source of attraction he dug up the Earth to find lodestones (load = lead or attract). Lodestones contain magnetite, a natural magnetic material Fe3O4. This type of rock was subsequently named magnetite, after either Magnesia or Magnes himself. Lodestones were used to tell direction. The most popular legend accounting for the discovery of magnets is that of an elderly Cretan shepherd named Magnes. Legend has it that Magnes was herding his sheep in an area of Northern Greece called Magnesia, about 4,000 years ago. Suddenly both, the nails in his shoes and the metal tip of his staff became firmly stuck to the large, black rock on which he was standing. To find the source of attraction he dug up the Earth to find lodestones (load = lead or attract). Lodestones contain magnetite, a natural magnetic material Fe3O4. This type of rock was subsequently named magnetite, after either Magnesia or Magnes himself. Lodestones were used to tell direction. http://www.howmagnetswork.com/history.html

22 Permanent magnets

23 Permanent Magnets A permanent magnet is a man-made object with a magnetic field around it. It has parts that are usually labeled as North and South. It will keep its magnetism for a long period of time. A permanent magnet can be demagnetized by heat, hammering and by other magnets. A permanent magnet is a man-made object with a magnetic field around it. It has parts that are usually labeled as North and South. It will keep its magnetism for a long period of time. A permanent magnet can be demagnetized by heat, hammering and by other magnets. http://www.coolmagnetman.com/images/alnico2.jpg

24 Examples of permanent magnets bar horseshoe donut

25 Temporary magnet

26 Temporary Magnets A Temporary Magnet is an object which has a magnetic field around it for a short period of time. An example of a temporary magnet is an electromagnet.

27 Examples of temporary magnets Electromagnet

28 A temporary magnet made by passing an electric current through a wire coiled around an iron bar.

29 H H The strength of the electromagnet depends on the strength of the power source and the number of coils wrapped around the bar. How can we make this electromagnet stronger?

30 Electromagnet A junkyard is one place to see an electromagnet in action. A crane holding a huge electromagnet can be used to pick up scrap metal when current flows through it. When the crane operator wants to drop the scrap, he or she will simply shut off the current to the electromagnet. http://www.bbc.co.uk/schools/ks3bitesize/science/physics/magnetism_5.sht ml

31 Earth’s Magnetic Field T HE E ARTH DOES NOT CONTAIN A GIANT BAR MAGNET, BUT IT BEHAVES AS IF IT DOES. T HE E ARTH HAS A MAGNETIC NORTH POLE AND A MAGNETIC SOUTH POLE. http://www.bbc.co.uk/schools/ks3bitesize/science/physics/magnetism_5.sh tml

32 We use Earth’s magnetic field to figure out where we are.

33 Compass A compass is an object with a small magnetic section that detects the north pole of Earth and points to it. the north pole of a bar magnet is actually called the 'north-seeking pole', and it points to the Earth's magnetic north pole; the south pole of a bar magnet is actually called the 'south-seeking pole', and it points to the Earth's magnetic south pole. A compass is an object with a small magnetic section that detects the north pole of Earth and points to it. the north pole of a bar magnet is actually called the 'north-seeking pole', and it points to the Earth's magnetic north pole; the south pole of a bar magnet is actually called the 'south-seeking pole', and it points to the Earth's magnetic south pole.

34 Where am I? Where am I? The south pole of a magnet is attracted to the Magnetic North Pole of the Earth. The south pole of a bar magnet is labeled "N." This can be confusing. A famous aviator nicknamed "Wrong Way Corrigan" flew from New York to Ireland when he was supposed to be going to Kansas. He claimed he followed the wrong end of his compass. The south pole of a magnet is attracted to the Magnetic North Pole of the Earth. The south pole of a bar magnet is labeled "N." This can be confusing. A famous aviator nicknamed "Wrong Way Corrigan" flew from New York to Ireland when he was supposed to be going to Kansas. He claimed he followed the wrong end of his compass.


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