Sound

Sound

Lesson Objectives

1. Explore the concepts of sound wave, loudness of sound, amplitude, frequency and pitch.

2. Formulate the relationship between the loudness of the sound and the amplitude.

3. Investigate the relationship between the pitch of the sound and the frequency using tuning forks.​

Subject | Science

Multiple Choice

When people speak their ________ vibrate.

• Ear drums

• Vocal chords

• Ears

• Tongue

Open Ended

Name five things that produces sound.

Open Ended

How is sound produced?

• Requires a Medium

• Cannot travel in a Vacuum

• Speed: Gas < Liquid < Solid

Propagation of Sound

Multiple Choice

Sound waves are what kind of wave?

• Longitudinal
• Transverse
• Surface
• Electromagnetic

The frequency of a wave is the number of wavelengths that pass through a point in one second. It is also described as the numbers of vibrations a body makes in one second. It is denoted by ‘f’.

It is measured in hertz (Hz).​

​Frequency

Low Frequency=Low Pitch=Dull Sound

High Frequency=High Pitch=Sharp Sound

Multiple Choice

What is frequency?

• the number of vibrations per second
• how high or low a sound is
• the loudness or softness of a sound
• the back and forth movement of matter

Multiple Choice

Which of the sounds, A or B, has the lower frequency?

Draw

Sketch two sound waves with different pitches (frequencies) and label them.

Multiple Choice

Sound is a form of energy produced by ______________.

• Vibrations

• Distances

• Prisms

• Forces

Multiple Choice

In a guitar, a thin string vibrates with high frequency than a thick string. Therefore, a thin string produces high pitch sound.

• True

• False

Multiple Choice

A sound with a high frequency has a _____ pitch. A sound with a ____ frequency has a low pitch.

• high, low

• low, high

• medium, high

• high, medium

Amplitude is the measure of displacement of vibrating body on either side about its mean position.

Amplitude is measured in metre and generally denoted by ‘a’.

Greater the energy a wave carries, the larger is its amplitude​.

​Amplitude

​

Low Amplitude=Low Energy=Low Intensity

​

High Amplitude=High Energy=High Intensity

Open Ended

What makes a sound loud or soft?

• A loud sound can be produced by striking the cymbals hard and a soft sound can be produced by striking them gently.​

• Loud sounds have more energy than soft sounds.

• The amount of energy that a wave carries across a unit area in each second is the intensity of the sound.

• The intensity of sound waves is related to the amplitude.

• The intensity of sound waves is measured in decibels (dB).​

​Loudness of Sound

Multiple Choice

______________ sounds have a larger amplitude

• Quiet

• Loud

Multiple Choice

What happens when you increase the amplitude of a sound?

• it makes the sound louder
• it makes the sound travel faster
• it increases the wavelength of the sound
• it increases the frequency of the sound

Multiple Choice

This is the unit used to measure the volume of a sound. 

• Decibel
• Medium
• Vibration
• Oscilloscope

Multiple Choice

Which of the following would produce the loudest sound?

• jet plane
• pin falling
• doorbell
• whisper

Multiple Choice

Which sound wave has the lowest pitch?

Open Ended

Why do we see lightning before thinder?

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Multiple Choice

Which state of matter do sounds travel fastest in?

• Solid

• Liquid

• Gas

• Plasma

Multiple Choice

Why does sound travel faster in solids than in liquids or gases.

• They are harder.

• The particles are closer together.

• Solids have more energy.

• Gases fill their container.

Multiple Choice

Roughly what is the speed of sound in air?

• The speed of light.

• About 10 m/s

• About 340 m/s

• About 1 500 m/s

Multiple Choice

The speed of sound depends on:

• Temperature

• Speed of the aircraft

• Direction

• Type of the sound source

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