Magnets

​Concept Check

​Write at least two things you noticed about the field lines

​Some materials are magnetic

Open Ended

Have a guess.

Is silver magnetic or non magnetic? Give a reason to support your idea. How could you check it?

​Silver is nonmagnetic because it is not attracted to magnet.

In their natural states, other metals such as aluminum, brass, copper, gold, and lead don't attract magnets because they are weak metals.​

​Magnetic Domain

​* Is a group of atoms whose magnetic fields are aligned

​* Is microscopic

​Types of materials --- Nonmagnetic

​* The magnetic fields of atoms are weak and point to different directions

​* The magnetic fields cancel each other out

​* The overall material is not magnetic and could not be turned into a magnet

​Types of materials --- Magnetic

​* The domains are not themselves aligned, so their fields cancel out

​* The domains are pulled by magnets and can be made into magnets

​Types of materials --- Magnets

​* A magnet is a material wherein the magnetic domains are aligned

​* The material is said to be magnetized

​Concept Check

Open Ended

Q1: How can a magnet attract a piece of iron that is not magnetized?

​The domains in the unmagnetized piece of iron are pulled to align by the magnetic field of the magnet.

​One domain pole is attracted to the magnet and the other domain pole is repelled.

Open Ended

Q2: Why will a magnet not pick up a 1-yen coin or a piece of wood?

​A 1-yen coin, a penny, or a piece of wood will not be picked up by a magnet because they have very weak magnetic domains which cannot be pulled into alignment by a magnet

​Earth is a magnet

​Earth is a magnet

​* The magnetic field of the Earth is similar to the magnetic field of a bar magnet

​* The field is due to the motion of Earth's iron and nickel core

​* Earth's magnetic field affects magnetic materials that are in it.

​* A magnetic compass needle points to north because of Earth's magnetic field.

​* Charged particles from the Sun are affected by Earth's magnetic field.

• The field deflects these particles, or t​urns them aside. Many of the particles are deflected towards the poles

​* An aurora is also commonly known as polar lights

​* The Northern Lights (aurora borealis) and Southern Lights (aurora australis) are due to the interactions of the charged particles with the atmosphere

​Concept Check

Open Ended

Q1: What force causes magnets to attract or repel one another?

Open Ended

Q2: Why are some materials magnetic and others are not?

​In most materials, the magnetic fields of atoms are weak and point in different direction, which cancels out. While in some like iron, cobalt, or nickel, their domains can be pulled to align making them magnetic.

Open Ended

Q3: Describe three (3) similarities between Earth and a bar magnet.

​* Like bar magnet, Earth has a north and south magnetic poles

​* Like bar magnet, Earth has a magnetic field

​* Like bar magnet, Earth is made mostly of iron

Open Ended

Q4: A needle is picked by a magnet. What can you say about the needle's atom?

​* The magnetic field is influenced by the magnetic field lines and the needle consists of atoms that deflects according to the field

Open Ended

Q5: The Northern Lights can form into lines in the sky. What do you think caused this effect?

​The aurora's characteristic wavy patterns are caused by the lines of force in the Earth's magnetic field.