Agenda – Core I• 8:15- 8:25 am - Warm up • Complete questions for Friday’s activity on

How We Hear pages. C 37-38• 8:25 – 8:40 - Interactive Notebook (Glue pages for chapter C-2) (Make-up work) (AR Books)• 8: 40 – 8:55 Review and Take Notes on Sound• (Frequency, loudness, • 8:55- 9:10 Activities p. C- 43 and - 48 (Review sound, vibrations)• 9:10 – 9:15 – Prepare for Wellness

Parts of a wave

Crest CrestTrough

Wavelength

Wave height

3

Longitudinal vs. Transverse Waves• Sound is a longitudinal wave, meaning that

the motion of particles is along the same direction of the force

• Transverse waves—motion of particles at 900 angles -water waves, light waves

Mechanical Waves transfer energy through matter – air, water, land

How water moves in a waveWater waves and sound waves transfer energy

through matter (mechanical waves):

Particles of water move around in circles. The farther below the surface,

the smaller the circle.

You can see the result of vibrations that create motion in the water to produce waves at the beach.

• As the wave slows, its crest and trough come closer together. The top of the wave is not slowed by friction and moves faster than the bottom.

Noise from a tuning fork causes ___?___ waves

Warm-UP: Complete KWL chart on SoundWhat do you know?

What do you want to know?What do you want to learn?

• are waves produced by vibrating objects that travels through a gas, liquid, or solid.

• Are compression waves• Travel as vibrations moving through

the air as a compression wave• Travel through air, but travel through

other materials.• Slinky – example of compression

waves.

• What is an example of an animal that sends out sound waves under water?

• Whales communicate through long distances by producing sounds under water

2.1 Facts about Sound C-37- (P13IN)

Sound :• is a mechanical wave• is a vibration that travels through

gas, liquid, or solid p. C 40-41• is a longitudinal wave• transfers energy through a medium • speed depends on its medium p.C-42

How Sound Waves are Produced? C38

• Sound waves are produced by vibration that are usually too small to see.

• Vibrations push and pull on the medium around them

• Vibrations send waves out in all directions

• Vocal cords are sound making instruments in the body.

When are your vocal cords tensed up and when are they relaxed? P. C 39

• Vocal cords are tense when you are about to speak or sing.

• Vocal cords are relaxed when you are breathing to allow air to pass in and out of your windpipe.

• End of notes for 2.1

2.2 Frequency Determines PitchDescription of Pitch ( write on page 15)• the quality of highness or lowness• Is determined by frequency• A low-frequency makes a low pitch• A high frequency makes a high-pitch• Rapidly vibrating object makes a high

sound• Slowly vibrating object makes a low

sound

Which diagram represents:1. High Pitch? 2. Low PitchWasher (larger, small), ball, cork

A.

B.

Activity - Hit several objects against a tuning fork and try to identify the objects by sound [large and small washer, ping pong ball,& cork]

High and Low Frequencies

• Most humans with good hearing can hear in a range of 20 hertz to 20,000 hertz

• Elephants may use infrasound – sound that travels through the ground , hearing another elephant 20 miles away.

• Ultrasound is above 20,000 hertz and can be used for communication, find food, image internal body parts and detect objects

Natural Frequencies• A tuning fork has a natural

frequency and can be used to tune a piano

• Each musical instrument and each human voice has it own particular sound called sound quality or timbre

The Doppler Effect • Motion causes the sound you hear from

a passing vehicle such as a train to seemingly change its pitch (highness or lowness of sound).

• Frequency and Pitch• The sound from a fire truck that is far

away reaches you ear at a low frequency. When the vehicle is S, the frequency is greater and the pitch is higher.

End Notes for 2.2

One String Guitar

One String Guitar

Activity

Construct a single stranded guitar to determine which pitch is higher.Number each distance 1-3 using 1 =lowest , 2= medium 3 = highest?

________10 cm, _______ 15 cm or ______20 cm

Observe the vibration of the rubber band. At what distances are vibrations faster?

________10 cm, _______ 15 cm or ______20 cm

2.3 Intensity Determines Loudness

• Intensity Depends on the amplitude of a sound wave

• . As the amplitude of a sound decreases, the frequency stays the same.

• When you take away energy or add energy to a sound wave, you change its intensity without changing its quality

2.3 Facts about Amplification

• Amplification• Increases the strength of an electrical signal• Is often used to increase the intensity of a sound

wave• Is experienced when you listen to a TV, radio or

stereo

2.3 Main Idea about Acoustics

• Acoustics is the scientific study of sound• Acoustics

Involves how sound is producedInvolves how sound is received and heardRefers to the way sound waves behave inside a

place

2.3 Intense Sound Can Damage Hearing

• Intense sounds can damage and destroy hair cells inside the inner ear called the cochlear.• Hairs cells make hearing possible• Ear damage can be lessened by wearing ear plugs or covering the ear

15.1 Properties of Sound

• If you could see the atoms, the difference between high and low pressure is not as great. Here, it is exaggerated.

Noise from a tuning fork causes ___?___ waves

Warm-UP: Complete KWL chart on SoundWhat do you know?

What do you want to know?What do you want to learn?

SoundThe Nature of Sound

Ears and Speakers

The Look of SoundSound WaveformsFrequency Content

Digital Sampling

What is Resonance?

Many objects have a natural frequency – vibrates in a regular pattern. (swings and pendulums)

What is Resonance?

Many objects have a natural frequency – vibrates in a regular pattern. (see saw and pendulum)

Resonance occurs whenever a sound wave has the same frequency as the natural frequency of an object. The sound will cause the object with the same natural frequency to vibrate.

What is Resonance?

Many objects have a natural frequency – vibrates in a regular pattern. (see saw and pendulum)

Resonance occurs whenever a sound wave has the same frequency as the natural frequency of an object. The sound will cause the object with the same natural frequency to vibrate.

Operation of the Cochlea

15.1 Recording sound

5. The electrical signal is amplified until it is powerful enough to move the coil in a speaker and reproduce the sound.

Wavelength from Sound Waves

15.2 The Doppler effect

• The shift in frequency caused by motion is called the Doppler effect.

• It occurs when a sound source is moving at speeds less than the speed of sound.

15.2 Sound Waves

A sound wave is a wave of alternating high-pressure and low-pressure regions of air.

The Physics of Sound

Common Sounds and their Loudness

UCSD: Physics 8; 2006 39Spring 2006

Example Sound SpeedsMedium sound speed (m/s)

air (20C) 343

water 1497

gold 3240

brick 3650

wood 3800–4600

glass 5100

steel 5790

aluminum 6420

http://hypertextbook.com/physics/waves/sound/

Resources - http://www.proteacher.org/c/657_Light_and_Sound.html

OSHA Regulation – Exposure

140

120

100

80

Decibel 60

- Noise Control Program 40 - Hearing Conservation 20

0 2 4 6 8 Exposure Duration (Hours)

Examples of electromagnetic waves

• Radio waves• Microwaves• infrared waves• ultraviolet light (UV light from sun)• X-rays • gamma-rays