SOUND

CLASS: 8 SUBJECT : SCIENCE

U - 6 : SOUND

SOUND WAVE

• A sound wave is a vibration that travels through a solid, liquid or gas such as the air or water.

• When there is a sound wave, the air particles don’t travel directly from the object making the sound to your ear. Sound waves are vibrations being passed on between particles.

• The particles vibrate in the same direction as the wave travels. Sound is an example of a longitudinal wave.

The loudness of a sound depends on how big the vibration of the air is.

• If air particles move back and forth a lot we hear a loud sound.

• If the source of a sound makes the particles vibrate more gently, we hear a quieter sound.

​LOUDNESS

​The pitch of a sound depends on how quickly the air vibrates.

• When air particles move back and forth quickly we hear a high pitch sound.

• When the air vibrates less quickly we hear a low pitch sound.

The number of vibrations each second is called the frequency and is measured in a unit called hertz (Hz).

The lowest pitch sound that most humans can hear is 20 Hz.

The highest pitch sound the average human can hear is 20,000 Hz.

​PITCH AND FREQUENCY

​To record or analyse a sound, scientists and musicians use a microphone to turn the sound into an electrical signal.

The electrical signal can then be displayed on a device called an oscilloscope and it produces a graph called a wave trace.

Multiple Choice

What type of wave is a sound wave? 

• Transverse Wave

• Longitudinal wave

• Tidal wave

• Light wave

Multiple Choice

What is the lowest frequency a human can hear ? 

• 30 Hz

• 2 Hz

• 20 Hz

• 20,000 Hz

Multiple Choice

Sound waves travel the FASTEST through _____________.

• gases

• liquids

• solids

• vaccum

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 following is the inverse of time period?

• Amplitude

• Frequency

• Pitch

• Quality

Multiple Choice

Sound does not travel in space because

• Space is too far away.

• There is no matter in space.

• Space is the final frontier

• Space has planets.

Multiple Choice

Speed of light in air is:

• 5100 m s^-1

• 3*10⁸m s^-1

• 330 m s^-1

• 3*10¹⁰ m s^-1

Multiple Choice

Ryan makes an instrument from a drinking straw as shown. If he cuts the straw in half, what will happen to the pitch?

• decreases

• it will remain the same

• increases

• 
  there is no sound

Multiple Choice

High pitch sounds are caused by a ______ vibration

• fast 

• slow

• hard

• sharp

•What is
sound?

•How do we
hear sounds?

•How do
sounds travel?

Sound is a

form of

energy, and it
comes from
vibrations.

Multiple Choice

Sound is a form of energy produced by ______________.

• Vibrations

• Distances

• Prisms

• Forces

Multiple Choice

Sound is caused by? 

• force

• vibrations

• instruments

Multiple Choice

Sound is a form of? 

• energy

• pitch

• volume

Multiple Choice

An object that does not vibrate cannot produce

• Sound

• Light

• Heat

• Electricity

Sound is a type
of energy made
from vibrations.
These vibrations

create sound

waves

Multiple Choice

When people speak their ________ vibrate.

• Ear drums

• Vocal chords

• Ears

• Tongue

Multiple Choice

An object that does not vibrate cannot produce

• Sound

• Light

• Heat

• Electricity

Multiple Select

tick the sound sources:

Multiple Choice

-............................ makes the sound.

• light

• vibration

•What is
sound?

•How do we
hear sounds?

•How do
sounds travel?

Multiple Choice

How does a sound wave interact with a human ear?

• vibrates the ear drum

• bounces off the ear canal

• rotates the ear drum

• vibrates the ear canal

Multiple Choice

What is this?

• Ear Drum

• Ear Canal

• Nerve

• Cochlea

Multiple Choice

What is this?

• Nerve

• Ear canal

• Cochlea

• Ear Drum

Multiple Choice

How is your eardrum like a real drum?

• It produces sound.

• It vibrates.

• It is frequently struck by the bones in your middle ear.

• It is hollow.

Multiple Choice

You stand outside a room that has the doors and windows closed. Why can you still hear sounds made inside the room?

• Vibrations are absorbed in the doors and windows

• Vibrations are reflected inside the room

• Vibrations travel through the door and the window

• Vibrations echo in the room

•What is
sound?

•How do we
hear sounds?

•How do
sounds travel?

Sound waves travel as vibrations passed between particles in solids, liquids and gases.

Multiple Choice

How does sound travel?

• Sounds travels in waves

• sound travels slow

• sound travels fast

• sound doesn't travel

Multiple Choice

Sound travels fastest in...

• solids

• liquids

• gases

• air

Multiple Choice

A place where no sound exists is...

• in the air

• under water

• space

• all of the above

Multiple Choice

Sound waves travel the SLOWEST through _____________.

• gases

• solids

• liquids

Multiple Choice

Why is sound able to travel faster through a solid than a gas?

• Gas molecules are packed tightly.

• Sound does not travel faster through a solid than a gas.

• Solid molecules are packed tightly.

• Gas molecules move slowly.

Multiple Choice

Sound does not travel in space because

• Space is too far away.

• There is no matter in space.

• Space is the final frontier

• Space has planets.

Multiple Choice

Why do we see lightning before we hear the thunder?

• Our eyes trick us

• Light travels faster than sound

• they're two separate things

Multiple Choice

Sarah and Maria made a telephone using two cans and a string. It was a very long string. Maria went upstairs in her house and Sarah stayed downstairs. Maria spoke softly into the can. "I can hear you!' Sarah said back. How can this happen?

• Sound waves travel through a vacuum.

• Sound waves travel from high to low.

• Sound waves travel through solids like the string.

• Maria talked so loudly that Sarah could hear her without the phone.

Multiple Choice

Which sentence BEST describes how sound moves?

• Sound can move through solids, liquids, or gases.

• Sound can move through empty space or through matter.

• Sound can move through solids and liquids but not through gases.

• Sound can move through liquids and gases but not through solids.

Multiple Choice

How can I produce a sound?

• heating an object

• hitting an object

• moving the mouth

• looking an object

Multiple Choice

Which of the following is an example of sound traveling through a solid?

• When you hear people in another room

• When you hear things underwater

• When you are talking to the person next to you

• Sound cannot travel through solids

Multiple Choice

A kind of energy that travels in waves that you hear

• Sound

• Crest

• Light

• Pitch

•What is amplitude,
pitch and frequency of a sound?

•How do we measure pitch and frequency of sounds?

Amplitude is the volume of a sound wave shown by the height of the wave. Frequency of the wave determines the pitch. High frequency waves produce a higher pitch.

Volume or loudness of a sound is measured in decibels.

Frequency of the sound wave is measured in Hertz.

Multiple Choice

The height of a sound wave graph is related to what?

• Amplitude (loudness)

• Pace (speed)

• Key

• Tone

Multiple Choice

the number of vibrations per second

• vibration

• volume

• pitch

• frequency

Multiple Choice

the loudness of a sound

• vibration

• pitch

• volume

• frequency

Multiple Choice

What is the frequency of a sound measured in?

• Gigabytes

• bits

• Hertz

• Bytes

Multiple Choice

Large vibrations cause ... sounds

• Loud

• Quiet

• Low

• Lowest

Multiple Choice

Pitch means.....

• How far or close a sound is

• How sound travels

• How high or low a sound is

• How vibrations happen

Multiple Choice

The volume of a sound is measured in units called ________

• decibels

• liters

• sound waves

• inches per minute

•What is an echo?

•How do animals use echoes?

•How do humans use echoes?

Sound waves can be reflected. We hear this reflected sound as an echo.

Hard, smooth surfaces are good at reflecting sound while soft, rough surfaces are good at absorbing sound.

Multiple Choice

The reflection of sound waves off of a hard surface can create ______.

• A wave

• An echo 

Multiple Choice

Soft surfaces _______ sound waves. 

• Reflect

• Absorb

Multiple Choice

How are echos made?

• Echos are made when sound waves are absorbed

• Echos are made when sound waves enter our ear

• Echos are made when sound waves are reflected off a surface

Multiple Choice

Why don't we hear an echo in rooms with lots of furniture?

• Because if sound waves meet a hard surface they are absorbed.

• Because if sound waves meet a soft surface they are absorbed.

• Because sound waves bounce back

• Because sound waves don't exist

Multiple Choice

Fill in the blank. Sound waves can only bounce off smooth, ____ objects?

• Rubber

• Soft

• Squishy

• Hard

Some animals such as bats, whales, dolphins and porpoises use a technique called echolocation to locate objects in their environment. They emit high frequency sound waves and use the echoes to find the object.

Humans use echoes in oceanography, medicine

and aviation. Boats use sonar to measure depth of the ocean. Radar is used to locate aircraft and ultrasound used

to scan babies.

Multiple Choice

Some animals use this to navigate and hunt

• frequency

• echolocation

• vibration

Multiple Choice

Which mammal uses sonar to detect objects in the dark?

• Mouse

• Dog

• Bat

Multiple Choice

You cannot hear ultrasound because it is:

• too loud

• too quiet

• high frequency

• low frequency

Multiple Choice

What is ultrasound mostly used for ?

• Shipping

• Military

• Medical use

• Firefighter

Multiple Choice

 The sonar that boats use for ultrasound is to determine the distance that an object is underwater.

• True

• False

Multiple Choice

Ultrasound waves are sound waves that are too low pitched for the human ear to hear.

• True

• False

Multiple Select

Which of these animals use(s) echolocation? Choose all that apply.

• bats

• dolphins

• elephants

• cats

• owls

Multiple Choice

________________________ is the use of echos, or reflected sound, to find objects.

• ultrasound

• sonography

• echolocation

• reflexology

Multiple Choice

_______________________ is a a system that uses sound waves to determine locations of objects.

• GPS

• sonar

• ultrasound

• echolocation

Multiple Choice

How does an echo occur?

• sound travels faster than light

• sound bounces off solids

• sound is absorbed by solids