Detailed Lesson Note
Subject: Basic Science
Class: JSS 3 (Grade 9)
Topic: Light Energy
Sub-Topic: Refraction of Light and Its Application, Vision, Dispersion
of Light, Rainbow
Duration: 40 minutes
Date: To be inserted by the teacher
Period: To be inserted by the teacher
Average Age of Students: 14 years
Class Size: 30
Instructional
Objectives
By the end of the lesson, students
should be able to:
- Define refraction of light and mention one of its
applications. (Lower domain – Knowledge/Recall)
- Explain how the human eye enables vision. (Middle
domain – Comprehension)
- Analyze how dispersion of light occurs using a prism
and evaluate its significance. (Higher domain – Analysis/Evaluation)
- Construct an explanation of how a rainbow is formed and
justify its link with dispersion. (Higher domain –
Synthesis/Evaluation)
Instructional
Materials
- Torchlight/sunlight through a hole
- Glass prism
- Clear glass of water and pencil
- Chart/diagram of the human eye
- Chart showing colours of the rainbow
Reference
Materials
- Basic Science for Junior Secondary Schools – UBE
Edition
- Teacher’s Guide/Notes
Lesson
Development
Step
1: Introduction (5 minutes)
Teacher’s Activities:
- Greets students and checks attendance.
- Asks a lead-in question: “Have you ever noticed that
a stick placed in water looks bent? Why do you think that happens?”
- Uses responses to introduce the topic Light Energy.
Students’ Activities:
- Answer the question (e.g., “It looks bent because of
water”).
- Listen attentively.
Learning Point: Students’ interest is aroused, and connection is made with
real-life experience.
Step
2: Presentation (25 minutes)
Part
A: Refraction of Light and Its Application (6 minutes)
Teacher’s Activities:
- Defines refraction as the bending of light when
it passes from one medium to another (air to water/glass).
- Demonstrates with a pencil in water.
- Mentions applications: eyeglasses, cameras,
microscopes, magnifying lenses.
Students’ Activities:
- Observe demonstration.
- Define refraction in their own words.
- Mention examples of applications.
Part
B: Vision (7 minutes)
Teacher’s Activities:
- Explains that vision occurs when light reflects from
objects and enters the eye.
- Shows diagram of the human eye and points out parts:
cornea, lens, retina, optic nerve.
- Explains that the lens focuses light on the
retina to form images.
Students’ Activities:
- Study the diagram of the eye.
- Discuss how we see.
Part
C: Dispersion of Light (6 minutes)
Teacher’s Activities:
- Defines dispersion as the splitting of white
light into seven colours.
- Uses prism experiment with a torchlight.
- Writes spectrum colours on the board: Red, Orange,
Yellow, Green, Blue, Indigo, Violet (ROYGBIV).
Students’ Activities:
- Watch spectrum demonstration.
- Recite and list the colours in correct order.
Part
D: Rainbow (6 minutes)
Teacher’s Activities:
- Explains that a rainbow forms when sunlight passes
through raindrops, which act like prisms.
- Connects rainbow formation to dispersion of light.
- Asks students: “When last did you see a rainbow, and
what time of day was it?”
Students’ Activities:
- Share experiences.
- Relate rainbow formation to dispersion.
Step
3: Evaluation (7 minutes)
Teacher’s Questions:
- What is refraction of light?
- Mention one application of refraction.
- Explain briefly how the eye enables vision.
- What is dispersion of light?
- List the seven colours of the spectrum.
- How is a rainbow formed?
Students’ Activities:
- Answer orally and in writing.
Step
4: Conclusion (3 minutes)
Teacher’s Activities:
- Summarizes lesson points:
- Refraction = bending of light.
- Vision = function of the eye using lens and retina.
- Dispersion = splitting of white light into colours.
- Rainbow = natural dispersion of light in raindrops.
- Encourages students to observe these phenomena in daily
life.
Students’ Activities:
- Listen attentively and copy summary.
Assignment
- Draw and label a simple diagram of the human eye.
- List three applications of refraction of light in
everyday life.
- State the colours of the rainbow in order.
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