U6.S9. Sound and space

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

Multiple Choice

What two factors effect the amount of energy a wave has?

• Frequency and wavelength
• Frequency and amplitude
• Amplitude and rest
• Wavelength and crest

Multiple Choice

What is the amplitude of this wave?

• 4

• 8

• 2

• 6.3

Multiple Choice

You can't hear sounds in outer space because there is no

• medium

• light

• energy

• heat

Multiple Choice

All waves carry ________ as they travel from one place to another.

• matter

• space

• energy

• water

Multiple Choice

High frequency sounds have _______ pitch

• HIgh

• Low

Multiple Choice

High Amplitude =__________________

• Louder sounds
• Quieter Sounds

Multiple Choice

The unit for measuring frequency is the ---

• Joule

• Hertz

• Gram

• Newton

Multiple Choice

The material in which a wave passes through is called____

• radiation
• particles
• medium
• space

Multiple Choice

What does pitch depend on?

• amplitude 
• frequency
• intensity 
• volume of sound

Multiple Choice

Sound waves cannot travel through _________.

• paper

• milk

• hydrogen

• empty space

Multiple Choice

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

• Decibel
• Medium
• Vibration
• Oscilloscope

Multiple Choice

Which instrument creates sounds with the lowest pitch?

• cello

• viola

• violin

Multiple Choice

The number of vibrations that occur in a period of time.

• pitch

• loudness

• frequency

Multiple Choice

Which of the following reasons is why tectonic plates move?

• The mantle has convection currents and the crust float and moves with these currents.

• The gravitational pull of the moon pulls differently on the different thicknesses of the plates.

• The inner core is spinning and moves the tectonic plates.

• The daily move of people, car, buses, trains, and ships create tectonic plate movement

Multiple Choice

Which of the follow is the best reason why the warm water rises and the cool water sinks in a convection current?

• The cool water is less dense than the warm water because the particles are moving faster.

• The cool water has faster moving particles which cause less space between the particles.

• The warm water had particles moving at a faster speed which causes more space between the particles, making it less dense.

• The warm water particles are moving slower which decreases the space between the particles making it more dense.

Multiple Choice

Which of the following best describes why the Earth's plates move?

• Heat moving from sun's rays reflect off the moon to cause plate tectonic movement

• Heat from the Core makes mantle material change densities and rise, which causes movement in the mantle

• Convection in the core causes the density to rise and make the Earth's inner layers spin

• Convection currents in the atmosphere push down on the plates causing movement

Multiple Choice

Which of the following is evidence to support the Theory of Continental Drift?

• Jigsaw puzzle continents

• Fossils of the same plant and animal spanning different continents

• Rock patterns spanning different continents

• A fossil of a tropical flower in Antarctica

• All of the answer choices

Multiple Choice

Sound is a form of? 

• energy
• pitch
• volume

Multiple Choice

Which device measures sound waves?

• Oscilloscope

• Stethoscope

• Antenna

• Microscope

Multiple Select

What type of interference is represented in the diagram?

• Constructive

• Destructive

• Cancellation

• Reinforcement

Multiple Select

What type of interference is represented in this diagram?

• Constructive

• Destructive

• Cancellation

• Reinforcement

Multiple Choice

You and your father inspect an empty house with the hopes of buying it. You walk through the rooms talking to one another, and you notice that your voices and footsteps are echoing in the big, empty house. What causes the echo?

• sound waves reflecting off smooth, hard surfaces throughout the house

• sound waves moving around the large rooms

• sound waves moving slowly through air

• sound waves refracting around corners in the empty rooms

Multiple Choice

Good sound absorber

• marble tile

• soft board

• concrete wall

• aluminium sheet

The earth moves!

Our earth moves! We have many pieces of evidence for this some we can even feel; like earthquakes. So what is causes the movement? Magma! Deep in the Earth, molten rock churns as it heats and cools in convection currents. This moves the crustlike plates on top, and even creates and new and destroys old plates. *VIDEO TIME*

Multiple Choice

This evidence shows ancient animals lived on several continents, even though they are an ocean apart.

• Mountain Range Evidence

• Glacial Evidence

• Fossil Evidence

Multiple Choice

Similar patterns are found around the world in high peaks.

• Mountain Range Evidence

• Glacial Evidence

• Fossil Evidence

Multiple Select

Mark only those that are evidence for Plate Tectonics:

• Rock Strata

• Porosity

• Fossil Record

• Acceleration

• Continental Drift

How do the plates ACTUALLY MOVE?

• Convection currents in the asthenosphere drive the movement of lithospheric plates

How does a convection cell occur?

• Hot magma in the asthenosphere begins to rise, similar to the way hot air rises.

• As it rises to the top of the asthenosphere, it cools and becomes more dense.

• This cooler, dense magma then sinks again. As it sinks, it gets warmer, until the process begins again

• This movement of magma is what drives the plates to move.

Multiple Choice

The idea that the continents were once part of a single landmass that broke apart and

moved is

• Continental Drift

• Tectonic Plates

• Transform

Multiple Choice

The collision theory suggests that an object called Theia collided with Earth. Which of these planets is closest in size to Theia?

• Earth

• Moon

• Venus

• Mars

Multiple Choice

The collision theory for the formation of the Moon describes an object the same size as Mars. What was this object?

• an asteroid

• a newly formed star

• a newly formed planet

• a comet from outside the Solar System

Multiple Choice

The collision theory is a theory of how the Moon was formed. It refers to a collision that happened relatively soon after the formation of the ...?

• universe

• Solar System

• Milky Way

• Moon

Multiple Choice

Which evidence supports the collision theory?

• The Moon has a small iron core, similar to the Earth

• Venus has no moon

• The Moon is Earth's only permanent natural satellite

• The surface of the Earth does not appear to ever have been molten

Multiple Choice

Which evidence contradicts the collision theory?

• Samples of rock from the Moon show that its surface was once molten

• Similar collisions causing rings of rock and dust outside the Solar System

• The collision theory fits with the theory of how the Solar System was formed

• None of them

Multiple Choice

Nebulae are clouds of ... ?

• Phineas and Ferb

• dust and gas

• Bonnie and Clyde

• atoms and molecules

Multiple Choice

Nebulae are primarily composed of what element?

• Hydrogen

• Helium

• Iron

• Oxygen

Multiple Choice

Which of these statements is correct?

• all nebulae act as stellar nurseries

• only some nebulae act as stellar nurseries

• no nebulae ever act as stellar nurseries

• most nebulae are smaller than the Sun

Multiple Choice

"Nebula" is Latin for ___

• cloud

• gas

• glow

• colour

Multiple Choice

Dust clouds that reflect the light of nearby bright massive stars are called ___

• emission nebulae

• mirror nebulae

• reflection nebulae

• gas nebulae

Multiple Choice

What force acted on the massive nebula to collapse it and eventually form our sun?

• electrostatic force

• gravity

• friction

• strong force

Multiple Choice

Arrange the sequence in the formation of Moon based on Collision Theory.

A: Rocks and dust are formed by the collision.

B: A newly formed planet (same size as Mars), named Theia, collided with the Earth.

C: Rocks and dust are pulled together by the force of gravity to form the Moon.

• A -> B -> C

• A -> C -> B

• B -> C -> A

• B -> A -> C

Multiple Select

Nebulae are clouds of ______ and ______ in space.

• Rocks

• Dust

• Gas

• Stars

Multiple Select

The gases in nebulae are ........ and ......

• oxygen

• carbon dioxide

• hydrogen

• helium

Multiple Choice

Stellar nurseries are area in space where ________ are formed.

• planets

• stars

• dust

• moons

Multiple Choice

The tectonic plates on the Earth's surface move due to ......

• gravity pull by the Sun

• gravity pull by the Moon

• convection current in the mantle

• fossils movement

Multiple Choice

Plate boundaries are places where two tectonic plates joined. Below are the events due to the movement of tectonic plates, EXCEPT:

• volcanic eruption

• earth quake

• mountain building (fold mountain)

• typhoon

Multiple Select

Which of the followings are the evidence(s) of tectonic plates?

• jigsaw appearance of continental coast

• location of volcanoes and earthquakes

• Fossil record

• Alignment of magnetic materials in the Earth's crust