Presentation on Theme: Magnetism :

1 Magnetism

2 Activating Strategy
With a partner, take the list of everyday objects provided by the teacher and identify those objects that have or use magnets.
Instructional Approach(s): Think-pair-share. The teacher should use the slide to activate students prior knowledge.

3 Essential question: how do the properties of magnets explain why some materials are magnetic and some are not?
Instructional Approach(s): The teacher should introduce the essential question and the standard that aligns to the essential question

4 Standard: S8P5c. Investigate and explain that electric currents and magnets can exert force on each other.
Instructional Approach(s): The teacher should introduce the essential question and the standard that aligns to the essential question

5 A magnet is any material that attracts iron or materials containing iron.
Students should define magnet on their notes sheet.

6 Properties of Magnets Activity
Place students into groups and give each group 2 bar magnets, some small metal objects and a variety of small non-metallic objects. The task is for groups to describe as many properties of magnets as they can (using the guided instructions sheet). Give students minutes maximum. After 20 minutes, discuss the findings with the class.

Magnetism

7 Properties of Magnets All magnets have two poles
Magnets exert forces on each other
Magnets are surrounded by a magnetic field
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

8 All Magnets have Two Poles
Each end of the magnet is called a magnetic pole
One end of the magnet always ends up pointing to the north. It is called the north pole
The opposite end of the magnet points to the south and is called the south pole
Magnetic poles are always in pairs (one north, one south)
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

9 All Magnets have Two Poles
If a magnet is broke in half, each half gains a new pole
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

10 Magnets Exert Forces on Each Other
As observed in the Properties of Magnets Activity, when you bring two magnets close together, the magnets exert a magnetic force on each other
These magnetic forces result from electric charges in the magnets. What causes the electric charge?
Remind students that gaining or losing electrons causes electric charge.

11 Magnets Exert Forces on Each Other
The force can either push the magnets apart or pull them together
The magnetic force between magnets depends on how the poles of the magnets line up. Like poles repel, and opposite poles attract
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

12 After discussing the slide, students should complete the magnet images on their notes sheet
13 Attract or Repel Activity
Each student will be given a paper magnet. When instructed, the student will find a partner based on the teacher’s directions of “Attract” or “Repel”
Instructional Approach(s): Attract or repel activity(on resource page)

14 Distributed Summarizing
A magnet is similar to _____________________ because ______________
Instructional Approach(s): Formative assessment. Each student should complete the summarizer. The teacher should use the summarizer to determine the level of student mastery and if differentiation is needed.

15 Magnets are surrounded by a Magnetic Field
The shape of a magnetic field can be shown with lines drawn from the north pole of a magnet to the south pole as shown in the diagram below
Magnetic field lines show both the direction and the strength of a bar’s magnetic field
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

16 Magnets are surrounded by a Magnetic Field
The closer together the lines, the stronger the field
The lines around a magnet are closest together at the poles, where the magnetic force is strongest
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

17 Field lines that curve toward each other show attraction.
Opposites Attract
Field lines that curve toward each other show attraction.
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

18 Field lines that curve away from each other show repulsion.
Likes Repel
Field lines that curve away from each other show repulsion.
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

19 Field Lines in a Horseshoe Magnet
Instructional Approach(s): The teacher should present the illustration on the slide to provide an example of magnetic fields in different magnets

20 The Earth behaves as if it has a bar magnet running through its center
The Earth behaves as if it has a bar magnet running through its center. The poles of this imaginary magnet are located near Earth’s geographic poles.
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

21 Magnets in Motion
Instructional Approach(s): Magnets in motion activity (optional)

22 Examining the Magnetic Field Activity
In groups, students are given two bar magnets and a tapped petridish filled with iron fillings. Students should explore what happens to the iron fillings when a bar magnet is placed under the petri dish. If possible, students should explore how the iron filling react when two magnets are placed near each other under the petri dish.

23 Magnets are surrounded by a Magnetic Field
The shape of the magnetic field surrounding a magnet can be seen by observing the shape of iron filings when placed near a magnet
Instructional Approach(s): The teacher should present the information on the slide to provide a real life example of magnetic fields

24 Magnetic Fields
-projects/discoveries/magnetic-fields/p/magnet- and-iron-filings
Instructional Approach(s): The teacher should present the link on the slide to reinforce magnetic fields

25 Whether a material is magnetic depends on the material’s atoms
The Cause of Magnetism
Whether a material is magnetic depends on the material’s atoms
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

26 The Cause of Magnetism
As electrons in atoms move around, a magnetic field is generated. The atom will then have a north and south pole.
The atoms group together in tiny areas called domains. Each domain is like a tiny magnet.
In most materials, such as copper and aluminum, the magnetic fields cancel each other out because the domains are randomly oriented (as shown below)
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

27 The Cause of Magnetism
In materials such as iron, nickel, and cobalt, the north and south poles of the atoms in a domain line up and make a strong magnetic field (as shown in the diagram below)
The arrangement of domains in an object determines whether the object is magnetic
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

28 The Cause of Magnetism
Instructional Approach(s): The teacher should present the illustration on the slide to provide an example of magnetized and demagnetized domains

29 Demonstrating a Magnetic Object Activity
Students are put into groups of 4-6. Each group is going to represent an object. Give each student in each group one of the Domain arrangement pieces. When instructed by the teacher, each group should arrange or align their domains based on the teacher stating whether they are a magnetized or demagnetized object.

30 If the arrangement of domains in an object determines whether the object is magnetic, is there a way to demagnetize an object? If so, how?
Instructional Approach(s): The teacher should present the information on the slide to introduce magnets demagnetized

31 Losing Alignment The domains of a magnet may not always stay lined up
When domains move, the magnet is demagnetized, or loses it magnetic properties
What are some ways you think a magnet might be demagnetized?
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

32 Ways to demagnetize (move domains)
Losing Alignment
Ways to demagnetize (move domains)
Dropping a magnet or hitting it too hard
Putting the magnet in a strong magnetic field that is opposite to its own
Increasing the temperature of a magnet (in higher temperatures, atoms vibrate faster so they may no longer line up)
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

33 Making Magnets
You can make a magnet from something made of iron, cobalt, or nickel. You just need to line up the domains.
You can magnetize an iron nail by dragging a magnet down it many times (in one direction)
The domains in the nail line up with the magnetic field of the magnet. So, the domains in the nail become aligned.
As more domains line up, the magnetic field grows stronger.
Instructional Approach(s): The teacher should present the information on the slide while the students record the important information on their notes

## History of Permanent Magnets

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### Pin Board Magnet Neo Sphere N42 15mm

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