7L Sound

Question 1

Making Sounds

Answer 1

Sounds are made by something vibrating.

Question 2

Intensity

Answer 2

How loud or soft a sound is- its volume.

Question 3

Pitch

Answer 3

How high or low a sound is.

Question 4

Frequency

Answer 4

The number of vibrations each second.
The higher the frequency the higher the pitch.

Question 5

Hertz (Hz)

Answer 5

The units for measuring frequency.

Question 6

Amplitude

Answer 6

The size of vibrations.
The bigger the amplitude the louder the note.

Question 7

Humans Making Sounds

Answer 7

Two flaps (vocal folds) across the windpipe vibrate when air moves across them.

Question 8

Grasshoppers Making Sounds

Answer 8

Male grasshoppers chirp by rubbing one leg against a wing.

Question 9

Gorillas Making Sounds

Answer 9

Male gorillas thump their chests or thump the ground to threaten other males.

Question 10

Moving Sounds

Answer 10

Sounds can only travel through a medium (a solid, liquid or gas).

Question 11

Vacuum

Answer 11

A completely empty space. Sound cannot travel through.

Question 12

Particles

Answer 12

Tiny pieces of matter that make up everything.

Question 13

Sound Moving Through the Air

Answer 13

Air particles vibrate and cause nearby particles to vibrate so the vibrations spread through the air.

Question 14

Sound Wave

Answer 14

Formed by the moving vibrations.

Question 15

Pressure Wave

Answer 15

The air particles are pushed together in some place (high pressure) and spread out in other places

Question 16

Sound Wave Frequency

Answer 16

The number of waves passing a point per second.

Question 17

Sound Wave Amplitude

Answer 17

The distance moved by air particles as the sound wave passes.

Question 18

Energy

Answer 18

Energy is transferred from one place to another by sound waves. They do not transfer particles.

Question 19

Speed of Sound

Answer 19

Sound travels faster in solids because the particles are close together.

Question 20

Moving Away from A Source

Answer 20

As you move away from a source of sound, the energy carried has spread out further so there is less energy for your ear to detect- it sounds quieter.

Question 21

Ear Protection

Answer 21

Loud sounds damage our ears- people who work in noisy surroundings need ear protection. Certain soft materials (carpets, curtains, etc.) also absorb energy transferred by sound waves.

Question 22

How Ears Detect Sounds

Answer 22

sound waves enter the ear canal.

the eardrum (a thin membrane) vibrates.

vibrations pass to the tiny bones which amplify the vibrations.

vibrations pass to the liquid inside the cochlea.

tiny hairs inside the cochlea detect vibrations and create electrical signals (impulses).

impulses travel along the auditory nerve to the brain.

Question 23

How Microphones Detect Sounds

Answer 23

Sounds make a thin sheet of materials (a diaphragm) vibrate and electrical circuits convert these vibrations into electrical currents.

Question 24

Decibels (dB)

Answer 24

The units for measuring the loudness of a sound.

Question 25

Auditory Range

Answer 25

The range of frequencies an organism can hear
20Hz – 20000Hz in humans

Question 26

Infrasound

Answer 26

Sounds below 20Hz

Question 27

Ultrasound

Answer 27

Sounds above 20000Hz

Question 28

Using Sound

Answer 28

Sound is often used for communication.

Question 29

Transmitted

Answer 29

Energy from sound waves goes through some materials.

Question 30

Reflected

Answer 30

Energy from sound waves bounces off some materials.

Question 31

Using High Frequency Waves

Answer 31

Treat injuries

Clean delicate objects by making tiny bubbles that loosen dirt when the burst.

Question 32

Echo

Answer 32

A reflected sound

Question 33

Echolocation

Answer 33

Used by animals (bats, dolphins, etc.) to find their way around/find prey.

Question 34

Sonar

Answer 34

Pulse of ultrasound is given off and reflected by the sea bed. It is then detected by sonar equipment to find the depth.

Question 35

Longitudinal Waves

Answer 35

Particles vibrate in same direction wave is moving.

Question 36

Transverse Waves

Answer 36

Particles vibrate at right angles to direction wave is moving.

Question 37

Superposition

Answer 37

As waves pass through each other their effects add up or cancel out.