HOW DO WE USE ELECTRICITY AND MAGNETISM? (PART 2)C H A P T E R 1 2 : L E S S O N 5 :

What is Magnetism?

Magnetism is the force of attraction or repulsion of a magnetic material due to the arrangement of its atoms, particularly its electrons.

The ends of a magnet are where the magnetic effect is the strongest. These are called “poles.” Each magnet has 2 poles – 1 north and1 south.

Like repels like…

Opposites attract!

Types of Magnets

Bar magnet

Horseshoe magnet

Rod magnet

Ring magnet

Disc magnet

Wand magnet

Atoms themselves have magnetic properties due to the spin of the atom’s electrons.

Groups of atoms join so that their magnetic fields are all going in the same direction

When an unmagnetized substance is placed in a magneticfield, the substance can become magnetized.

This happens when the spinning electrons line up in thesame direction.

An unmagnetized substance looks like this…

While a magnetized substance lookslike this…

Iron

Lodestone (Magnetite)

MAGNETIC FIELDS

Magnetic field lines1. Leaves north pole &

enters south pole

2. Lines closer together = stronger field

NOTICE3. Strongest at the poles

4. Field lines start at the NORTH pole and travel towards the SOUTH pole

An area where the force exists; area where force is felt

The Earth is a magnet:

It exerts magnetic forces and is surrounded by amagnetic field that is strongest near theNorth and South magnetic poles.

We use the Earth’s magnetic field to find direction.

The needle of a compass always points towards the “North”

Iron

Nickel

Magnets are made from materials like:

Cobalt

ELECTROMAGNET

Electromagnetisma moving charge (electricity) produces a magnetic field

More coils of wire= more current = stronger magnet

Bigger battery = stronger magnet

A magnet with a field produced by an electric current

What is a magnet keeper?

- A magnet keeper is a bar made of soft iron or steel.

- It fits over the magnetic poles, helping to preserve the magnetic field during long periods of storage.

Magnet keeper

What is a magnet keeper?

- A magnet keeper is a bar made of soft iron or steel.

- It fits over the magnetic poles, helping to preserve the magnetic field during long periods of storage.

Magnet keeper

Safe handling of magnets.1) Do not bang magnets together because they will break and small pieces will go flying off.2) Wear safety goggles so that the small pieces will not go into your eyes.3) Don’t drop the magnets. Not only will they break, it will affect the strength of the magnet.

4) Slowly allow the magnets to come together.

5) Wear protective gloves.

7) Don’t heat it or place it in high temperatures as it gets weaker.

6) Health hazards when in contact with food and drinking water.

Storage of magnets.1) Don’t place strong magnets near video tape or audio tape or parts of the tape will be erased.2) Don’t place it near credit cards, the magnetic strip on the back will be erased.3) Don’t use magnets near mobile phones, interactive white boards or computers.

4) If placed close to a TV screen or computer monitor, the screen’s colour will become distorted.

5) Don’t store in moist places, like places where rainwater or dust can reach.

Recycling facilities

 

Vehicle scrappage

 

Industrial use of magnets