KS3+Magnetism

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10 AWESOME MAGNET TRICKS! [|Mr. Hacker] Published on 8 Feb 2017

Investigate and describe the properties of magnets Know about attraction and repulsion A magnet attracts magnetic materials such as __i ron __, __s teel ,__ cobalt and __n ickel .__

Magnetic poles are the parts of a magnet that exert the greatest force.

Magnetic poles occur in pairs usually called North (N) pole and South (S) pole.

A magnetic field is a volume of space where magnetic force is exerted.


 * U****nlike poles __ attract __, and l****ike poles __ repel __ each other.**

ex) Iron, cobalt, nickel, steel are magnetic materials || Non magnetic materials can not be attracted by the magnet. ex) cork, glass, plastic, rubber, wood || [|Understanding magnets]
 * Magnetic ** materials ** || ** non-magnetic materials ** ||
 * Magnetic materials can be attracted by the magnet.

Investigate magnetising iron
 * Magnetisation** is to give magnetic property by making all the magnetic domains pointing in the same direction.

//Methods of magnetising a magnet;// 1. Stroking a steel bar with a permanent magnet 2. Placing a steel bar in a solenoid carrying a large direct current

The magnetic domains point in random directions. The magnetic effects of the atomic magnets cancel out so there is no resultant magnetic effect.
 * Demagnetisation** is the process of removing magnetism from a magnet. __ Heat __ing and __ hammer __ ing cause the atoms of the magnet to vibrate vigorously, mixing up the directions of the magnetic domains.

//Methods of demagnetising a magnet;// 1. Heating 2. Hammering 3. Withdraw the magnet that is placed in a solenoid with an alternating current.

Recognize and reproduce the magnetic field pattern of a bar magnet. (Plot magnetic fields) [|Magnetic fields] Image from [|cyberphysics] || Consider some examples of the use of magnets Construct and use an electromagnet Research the use of magnets and electromagnets
 * The shape of a magnetic field can be shown by __i ron __ __f ilings __ or plotting __c ompasses .__**
 * [[image:sciencelanguagegallery/Field lines around a bar magnet.jpg caption="Field lines around a bar magnet.jpg"]] || [[image:sciencelanguagegallery/Magnetic field lines shown by compasses.jpg caption="Magnetic field lines shown by compasses.jpg"]] ||
 * Image from [|BBC bitesize] || Image from PMT wikispaces ||
 * [[image:sciencelanguagegallery/magnetic field lines.jpg width="566" height="297" caption="magnetic field lines.jpg"]] || [[image:sciencelanguagegallery/Magnetic field line by a bar magnet.jpg caption="Magnetic field line by a bar magnet.jpg"]]

1. Moving coil ammeter 2. Magnetic door catch 3. Loud speaker
 * Uses of permanent magnets**

1. Scrap yard crane 2. Electric bell 3. Circuit breaker
 * Uses of electromagnets**

* Describe what happens if you hold a nail or paper clip near the coil. Answer: The object __ gets pulled into __ the coil. An __ iron __ core at the centre of a coil of wire, __ increases __ the strength of an electromagnet. An electromagnet can be ** easily ** __turned__ on and off. This is why electromagnets can be used in scrapyards and as switches in electrical devices.
 * ** Homework due by 2 September : Learn how an electric bell works. **
 * ** Reference: page 200, Checkpoint Science Book 2 **