DETAILED LESSON NOTE
Subject: Basic Science
Class: JSS 3 (Grade 9)
Topic: Sound Energy
Sub-topic: Production, Propagation, Reflection, and Hearing of Sound
Week: Eleven
Duration: 40 minutes
Class Size: 30
Average Age of Students: 13 – 15 years
Date: To be inserted by the teacher
Instructional Materials:
- Tuning fork / bell / drum
- Ruler or desk (for vibration demonstration)
- Chart/model of the human ear
- Board and marker
Lesson
Objectives
At the end of the lesson, students
should be able to:
- Define sound, describe how it is produced, and state
how it propagates through different media (lower domain).
- Explain the concept of reflection of sound and give
real-life examples (middle domain).
- Analyze how the human ear hears sound and evaluate how
noise pollution can affect hearing, suggesting preventive measures (higher
domain).
Entry
Behaviour
Students already know that drums,
bells, and voices make sound when struck or spoken into.
Set
Induction (5 minutes)
- Teacher strikes a bell or drum and asks:
- “What happened when I hit this drum?”
- “How did you hear the sound even though you were not
touching it?”
- Students respond: “The drum made sound”, “The sound
travelled to our ears.”
- Teacher links responses: “Good! Today we will learn
how sound is produced, how it travels, how it reflects, and how we hear
it.”
Presentation
(30 minutes)
Step
1: Production and Propagation of Sound (10 minutes)
- Teacher explains that sound is produced by vibration
of objects.
- Demonstrates with tuning fork or striking ruler on desk
(students feel vibration).
- Explains propagation:
- Sound needs a medium (solid, liquid, or gas).
- Sound cannot travel in a vacuum.
- Speed of sound: fastest in solids, slower in
liquids, and slowest in gases.
- Students’ Activity:
Students strike their desks or rulers to feel vibration and explain how
sound is produced.
Step
2: Reflection of Sound (8 minutes)
- Teacher explains that sound can be reflected just like
light.
- Echo:
sound heard again after reflection from a large surface (e.g., mountain,
building).
- Reverberation:
when echoes overlap due to repeated reflections in a hall or empty room.
- Uses of reflection of sound:
- SONAR (ship navigation)
- Echolocation in bats and dolphins
- Measuring depth of the sea
- Students’ Activity:
Students give examples of places where echoes can be heard (halls, caves,
mountains).
Step
3: Hearing (12 minutes)
- Teacher shows a chart of the human ear and
explains its parts:
- Outer ear (pinna and ear canal): collects sound waves.
- Middle ear (eardrum and ossicles): transfers vibrations.
- Inner ear (cochlea and auditory nerve): converts vibrations into electrical signals sent to
the brain.
- Teacher explains dangers of noise pollution:
o
Can damage ear (hearing loss).
o
Causes stress, headache, lack of
concentration.
Preventive measures:
o
Avoiding very loud music.
o
Wearing ear protection in noisy
places.
o
Creating quiet environment for study
and rest.
Students’
Activity: Students identify parts of the ear
on chart and discuss how noise affects them.
Evaluation
(5 minutes)
Teacher asks the class the following
questions:
- Define sound and explain how it is produced.
- Why can’t sound travel in a vacuum?
- Explain the difference between echo and reverberation.
- How does the ear hear sound?
- Mention two negative effects of noise pollution and
suggest one way of preventing them.
Assignment
- Draw and label the human ear neatly.
- Write short notes on three differences between sound
and light.
References
- Basic Science for Junior Secondary Schools, Book 3
- Teacher’s Notes/Charts
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