Lesson Notes By Weeks and Term v4 - SHS 1
WAVES
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WAVES
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Subject: Physics
Class: SHS 1
Term: 1st Term
Week: 20
Grade code: 1.2.2.LI.1
Strand code: 2
Sub-strand code: 2
Content standard code: 1.2.2.CS.2
Indicator code: 1.2.2.LI.1
Theme: ENERGY
Subtheme: WAVES
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Have you ever put a spoon or a pencil in a glass of water and noticed that it looks bent or broken at the water's surface? Or have you ever tried to pick up something from the bottom of a bucket of water and missed it on the first try because it wasn't where it appeared to be? These are not magic tricks; they are everyday examples of a fascinating Physics concept called refraction. Today, we will explore why light bends when it travels from one material to another, like from the air into the water in a basin. Understanding this helps us understand how our eyes work, how glasses (spectacles) correct vision, and even how fishermen aim their spears to catch fish in our local rivers and lagoons.
This is the main content delivery part of the lesson. Part 1: What is Refraction and Why Does It Happen?
(Activity 1 - Collaborative Learning - 10 mins) Instruction: In your groups, pour water into a basin. Place a pencil or a straight stick obliquely (at a slant) into the water. Look at it from the side and from above. Observation: The pencil appears bent at the point where it enters the water. Discussion: Why do you think this happens? Let's find out.
Explanation: Refraction is the bending of a wave (in this case, light) when it passes from one medium to another. A medium is any substance that light can travel through, like air, water, glass, or even a diamond.
The key reason for refraction is a change in the speed of light. Light travels at different speeds in different media. It travels fastest in a vacuum (empty space). It travels slightly slower in air. It travels even slower in water. It travels slowest in materials like glass or diamond.