Lesson Notes By Weeks and Term v4 - SHS 1
MAGNETOSTATICS
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MAGNETOSTATICS
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Subject: Physics
Class: SHS 1
Term: 2nd Term
Week: 14
Grade code: 1.3.2.LI.1
Strand code: 3
Sub-strand code: 2
Content standard code: 1.3.2.CS.2
Indicator code: 1.3.2.LI.1
Theme: ELECTRIC FIELD, MAGNETIC FIELD AND ELECTRONICS
Subtheme: MAGNETOSTATICS
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Class: SHS 1 Period: [Period Number] Performance Indicator: By the end of the lesson, the learner will be able to: Define a magnetic field. Describe the properties of magnetic lines of force. Visualize and draw the magnetic field pattern around a bar magnet. Explain the behaviour of a freely suspended bar magnet in relation to the Earth's magnetic field.
(40 mins - Including Demonstration)
This section is best delivered with a mix of direct instruction and a live demonstration using the materials. A. What is a Magnet? A magnet is any material that can produce its own magnetic field and attract materials like iron, cobalt, and nickel. Every magnet has two poles: a North pole (N) and a South pole (S). The Law of Magnetism: Like poles repel each other (North-North or South-South). Unlike poles attract each other (North-South). B. The Magnetic Field The concept of a field is very important in Physics. Just like a hot waakye seller's aroma fills the air around her stall, a magnet creates an invisible area of influence around itself. Definition: A magnetic field is a region or space around a magnet where a magnetic force can be experienced (detected). If you bring another magnet or a magnetic material (like a paper clip) into this region, it will feel a push or a pull. C. Visualizing the Magnetic Field: Magnetic Field Lines We cannot see the magnetic field, but we can see its effect. We use imaginary lines called magnetic field lines or magnetic lines of force to represent it.
Demonstration (Experiential Learning): Place a bar magnet on a flat table. Cover it with a single sheet of A4 paper. Gently and evenly sprinkle iron filings from a shaker onto the paper. Tap the paper gently. Observation: The iron filings will arrange themselves into a distinct pattern of lines around the magnet. This pattern reveals the shape of the magnetic field.
Properties of Magnetic Field Lines (to be discussed while observing the pattern): Direction: They are directed away from the North pole and towards the South pole *outside* the magnet. They form continuous closed loops, going from South to North *inside* the magnet. We can show this direction by placing a small plotting compass at various points; the arrowhead of the compass will point along the field line. They Never Cross: Magnetic field lines can never intersect. If they did, it would mean that at the point of intersection, the magnetic force has two different directions, which is impossible. Strength Indication: The closeness (density) of the field lines indicates the strength of the magnetic field. Where the lines are closest together (near the poles), the magnetic field is strongest. Where the lines are farther apart, the magnetic field is weakest.