Waves 2 - Section 1: Sound

How does sound travel through a medium?

Success Criteria:

Today I know I have it when…

1. I can label the parts of the
   ear and how it processes
   sound.

2. I can describe how sound
   travels through a medium.

Today you need…

1.Pen/Pencil

2.

Glue/Tape

3.

Ear diagram

4.

INB

5.

Chromebook

Day 2

S8P4. Obtain, evaluate, and communicate information to support the claim that electromagnetic (light) waves
behave differently than mechanical (sound) waves.

Multiple Choice

How could you measure the speed of sound?

• Measure the time it takes for a pendulum to swing

• Measure the time it takes for a ball to bounce

• Measure the time for an echo to return

• Measure the time it takes for a bell to stop ringing

Multiple Choice

What happens to the wavelength of a sound wave when the speed increases?

• Wavelength increases

• Wavelength decreases

• Wavelength remains the same

Multiple Choice

What happens to the frequency of a sound wave when the speed changes as it enters a different medium?

• Frequency increases

• Frequency remains the same

• Frequency descreases

“

SOUND WAVES - compressional waves formed
from vibrating objects colliding with air molecules

▹ Remember compressional waves are made of compressions

and rarefactions.

Labelling

Label the wavelength, compression and rarefaction of the longitudinal wave.

Drag labels to their correct position on the image

wavelength

compression

rarefaction

5

Speed of Sound -
depends on temperature
and state of medium

▹ Sound travels in solids and

liquids - molecules are closer
together than gas molecules

▹As a medium temp rises,
molecules move faster
conducting sound waves faster.

HUMAN
HEARING

STAGE 2

The middle of the
ear has three bones
called the hammer,

anvil and stirrup

which amplify sound

waves

STAGE 1
Ear gathers

compressional
waves which

vibrate a tough
membrane called

the eardrum

STAGE 3
The inner ear

contains the cochlea

which vibrates

sending auditory
nerve impulses to

the brain

STAGE 4

The brain decodes
and interprets nerve

impulses

INTENSITY

The amount of energy that
flows through a certain
area in a given amount of
time.

LOUDNESS

The human perception of

sound intensity which is

measured in decibels

Open Ended

Is loudness the same for every individual? Why or why not?

PITCH - how high or low a sound seems to be, which is

related to frequency of a sound wave

SUBSONIC

< 20 Hz

HUMANS CAN HEAR

20 - 20,000 Hz

ULTRASONIC

> 20,000 Hz

• Complete slide 2 in your digital INB

• Don't forget to click the Quick Check when finished.

​Now YOU TRY!!!