SSC standard 7 Chap 4 Magnetism
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Transcript of SSC standard 7 Chap 4 Magnetism
+Objective
Research and record the discovery of magnets and materials that are attracted by magnets.
+Do Now
Write down examples of magnetism which you know
• Magnets have been known for centuries.
• The ancient Greeks used a stone substance called “magnetite.”
• They discovered that the stone always pointed in the same direction and that it attracts iron.
• Later, stones of magnetite called “lodestones” were used in navigation.
History
What is Magnetism?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 has2 poles – 1 north, 1 south.
Like repels Like repels like…like…
Opposites attract!Opposites attract!
Poles of a magnet always
Come in pairs!
If you cut a magnet If you cut a magnet in half,in half,
you get 2 magnets!you get 2 magnets!
S N S N S N
+Objective
SWBAT identify the properties and kinds of Magnetic materials
+Quick Review
Define “Magnetism”
What are the key words related to properties of the materials
+Ferro magnetic materials
Materials respond differently to the force of a magnetic field.
Materials that are strongly attracted by a magnetic force are called “Ferro magnetic materials”
Ferro = Latin word for Iron
Nickel, Cobalt, and ALNICO, an aluminum-nickel-cobalt alloy
+Video
Let us quickly summarize point wise
1.Definition of Ferromagnetic materials , Magnetic field
2.Properties of magnets
3.Examples of Magnetic substances
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