Physics - Senior Secondary 2 - Light waves

Light waves

Get it on Google Play
Get it on the Apple App Store
  1. Home
  2. Comprehensive Lesson Plan and Notes
  3. Senior Secondary 2
  4. Light waves

TERM: 1ST TERM

WEEK: 9
Class: Senior Secondary School 2
Age: 16 years
Duration: 40 minutes for each of 5 periods
Date:
Subject: Physics
Topic: Light Waves
Subtopics:
• Refraction of light through rectangular glass block
• Laws of refraction
• Real and apparent depth
• Total internal reflection
• Critical angle

SPECIFIC OBJECTIVES:
By the end of the lesson, students should be able to:

  1. Explain the laws of refraction of light.
  2. Understand real and apparent depth in a refracting medium.
  3. Demonstrate the phenomenon of total internal reflection.
  4. Calculate the critical angle for total internal reflection.
  5. Verify Snell's law using a rectangular glass block.

INSTRUCTIONAL TECHNIQUES:
• Explanation
• Demonstration
• Hands-on activity: Verification of Snell’s law using a rectangular glass block
• Video clips on refraction and total internal reflection

 

INSTRUCTIONAL MATERIALS:
• Rectangular glass block
• Laser pointer
• Protractor
• Whiteboard markers
• Physics textbook
• Snell’s law verification video

 

INSTRUCTIONAL PROCEDURES
PERIOD 1-5

PRESENTATION

STEP 1: INTRODUCTION
• The teacher will ask students about their understanding of refraction.
• The teacher will introduce the concept of light bending as it passes from one medium to another.

STEP 2: EXPLANATION
• The teacher will explain the laws of refraction and the concept of refractive index.
• The teacher will define real depth (the actual depth of an object) and apparent depth (how deep an object appears due to refraction).

STEP 3: DEMONSTRATION
• The teacher will use a rectangular glass block and a laser pointer to demonstrate refraction.
• Students will observe how light bends when passing from air into glass.

STEP 4: HANDS-ON ACTIVITY - VERIFICATION OF SNELL'S LAW
• The teacher will guide students to measure angles of incidence and refraction and calculate the refractive index using Snell’s law.
• Students will calculate the critical angle for total internal reflection.

STEP 5: NOTE TAKING
• The teacher writes a summary note on the board, which students will copy.

NOTE
Refraction of Light:
• Laws of Refraction: Light bends when it passes from one medium to another, and the angle of incidence is related to the angle of refraction through Snell’s law.
• Real and Apparent Depth: Real depth is the actual depth of an object, while apparent depth is how deep it appears when viewed through a transparent medium.
• Total Internal Reflection: Occurs when light passes from a denser to a less dense medium at an angle greater than the critical angle, causing it to reflect entirely within the denser medium.
• Critical Angle: The angle of incidence at which the angle of refraction is 90°.

 

EVALUATION

  1. What is Snell’s law?
  2. Define real and apparent depth.
  3. What is the critical angle, and how is it related to total internal reflection?
  4. Verify Snell’s law using the data you collected.

CLASSWORK:
• Calculate the refractive index for various materials using Snell’s law.
• Measure the critical angle for total internal reflection in a glass block.

 

CONCLUSION
• The teacher will review the students' results and provide feedback.
• Students will be encouraged to discuss applications of refraction, such as in optical fibers and lenses.