PROPOSED LESSON
PLAN/NOTE FOR THE
NINEHT WEEK ENDING 11th NOVEMBER, 2022
2022/2023 ACADEMIC
SESSION
SUBJECT: BASIC SCIENCE
TOPIC: SOUND ENERGY
CLASS: GRADE 9
NUMBER OF STUDENTS: 25
AVERAGE AGE: 11+ YEARS
GENDER: MIXED
PERIOD: 7th
AND 8th PERIOD ON TUESDAY AND FRIDAY RESPECTIVELY
TIME: 1:20-2:00
DURATION: 40 MINUTES
PER PERIOD
DATE: 07/11/2022
SPECIFIC OBJECTIVES: By
the end of the lesson the students should be able to;
1.
describe production of sound;
2.
explain transmission of sound.
ENTRY
BEHAVIOUR: The students are familiar with sounds from human, animals and
vehicles.
INSTRUCTIONAL TECHNIQUE: Visual,
questions, simulation.
INSTRUCTIONAL MATERIALS: Textbook,
lesson note, laptop, projector, marker, whiteboard.
DEVELOPMENT:
STEP 1: PRODUCTION OF
SOUND
Every day we hear sounds produced by living
things as well as non-living things. When we clap, a sound is produced. Sound
is a form of energy which produces a sensation of hearing in our ears. Sound
plays an important role in our lives. It helps us to communicate with one
another.
Sound can be produced by plucking,
scratching, rubbing, blowing or shaking different objects. This shows that
vibrating objects produce sound such as a vibrating rubber band. Vibration is a
kind of rapid to and fro motion of an object. For example, the sound of the human
voice is produced due to vibrations in the vocal cords. Musical instruments
such as a guitar produce sound due to vibration in its strings.
STEP 2: TRANSMISSION OF
SOUND
Sound is a mechanical wave. It needs a
medium such as solid, liquid or gas for its propagation. It cannot travel
through vacuum. The matter or substance through which sound is transmitted is
called a medium. Sound waves are longitudinal waves. A wave is a disturbance that
moves through a medium when the particles of the medium set neighbouring
particles into motion. When an object vibrates, it makes the particles of the
medium around it to vibrate. The particles do not move from one place to
another, but they simply oscillate back and forth about their position of rest.
They in turn produce similar motion in others. In this way, the disturbance is
carried forward but the particles of the medium do not move forward themselves.
This is what happens during propagation of sound in a medium. During the propagation
of the sound waves, the individual particles of the medium move in a direction
parallel to the direction of propagation of the disturbance.
The most common medium through which sound travels
is air. When a vibrating object moves forward, it pushes and compresses the air
in front of it which creates a region of high pressure and high density. This region
is called compression. This compression starts to move away from the vibrating
object. When the vibrating object moves backwards, it creates a region of low
pressure and low density which is called rarefaction. As the object moves back
and forth rapidly series of compressions and rarefactions is created in the
air.
These make the sound wave that it
propagates through the medium. Sound travels 330 meters in one second in air. It
takes about one-tenth of a second for the human ear to separate one sound from
another. The human ear can hear two sounds separately and distinctly only if
there is an interval of 0.1 seconds between the two. This is called persistence
of hearing.
EVALUATION: Oral
questions
1. What
is compression?
2. What
is rarefaction?
3. Write
briefly the characteristics of sound.
SUMMARY/CONCLUSSION: Sound is
produced by a vibrating object. It is a form of energy which produces a
sensation of hearing in our ears.
ASSIGNMENT:
1. What
is compression?
2. What
is rarefaction?
3. Write
briefly the characteristics of sound.
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