3 Sound WavesSound Waves: compressional waves that are produced when vibrations from an object collide with molecules
4 Sound wavesCan travel through solids, liquids and gases but not empty space
5 Speed of Sound Depends on......... 1. The type of medium (gas, liquid or solid) travels fastest in solids2. The temperature of the medium- travels through warm mediums faster
6 How we hear sound… 1. The outer ear gathers sound waves 2. The middle ear amplifies the sound waves3. The inner ear converts the sound waves to nerve impulses4. The nerve impulses travel to the brain to be decoded and interpreted
9 How we hear soundEardrum: a tough membrane in the ear that vibrates when sound enters itCochlea: a spiral-shaped, fluid filled cavity in the inner ear that vibrates and sends nerve impulses to the brain
10 Properties of SoundIntensity: the amount of energy that flows through a certain area in a specific amount of timeHigh intensity = high energyLoudness: the human perception of sound intensity
11 Properties of SoundDecibel (dB): a unit on the scale of sound intensity0 dB is the faintest sound humans can hear120 dB main cause pain and damage to ears
17 1. Which 2 animals have the largest hearing range. ______________ 2 1. Which 2 animals have the largest hearing range? ______________ 2. Which animal can hear the highest frequency sounds? ______ 3. What range of hearing does a fish have? __________ 4. Which animal has the smallest range of hearing? _______ 5. The range of a rodent's hearing is similar to that of a __________
18 What is the dB of a baby crying. What is the Hz of a baby crying What is the dB of a baby crying? What is the Hz of a baby crying? What is the dB of an airplane? What is the Hz of an airplane? What is the dB of birds? What is the Hz of birds?
19 Sonic Boom http://www.youtube.com/watch?v=-d9A2oq1N38
20 Moving soundDoppler effect: a change in the pitch of a sound wave due to the source of the sound movingToward: when the object is moving toward the observer, the pitch is higherAway: when the object is moving away form the observer, the pitch is lower
21 The Doppler Effect http://www.youtube.com/watch?v=VYVWhBCwipE
22 Using SoundSonar: a system that uses the reflection of underwater sound waves to detect objectsEquation: d = st/2guide-to-submarines-sonar-video.htm
23 Using Sound Echolocation: animals using sonar to locate prey
24 Using SoundUltrasound imaging: uses sound waves to produce images of internal body structures
25 Music Music: sounds produced in a deliberate pattern Instruments produce sound in different frequenciesNatural Frequencies: every material or object has a natural frequency at which it vibratesFrequencies of guitar strings depend on thickness, length and how tightly it's stretched.
26 MusicSound Quality: describes differences among sounds of the same pitch and loudnessEach instrument has its own unique sound quality
27 MusicResonance and music: the sound of music is amplified by the resonance of instruments
28 Types of instruments Strings: violin, cello, guitar Produce notes and the hollow chamber is the resonator (amplifier)Stretching the sting changes the pitch
29 Types of instruments 2. Brass and woodwinds: flute, trumpet, clarinet Air is blown through a reed an the air resonates in the chamber (amplifier)Most are wood but can be brass or other metals
30 Types of instruments 3. percussion: drums, xylophone, triangle Resonance happens in a chamber (amplifier)feature=related
31 BeatsBeat: occur when sound waves of almost the same frequencies interfere with each other forming a standing waveAcoustics: the study of soundUses reflection and absorption of sound waves to design concert halls and auditoriums
35 1. Sound travels faster in [ warm / cold ] air. 2. The bones of the middle ear serve to ______________ the sound.3. Sound moves through air by colliding with [ molecules / energy ]. 4. Sound moving through air is a [ transverse / compressional ] wave.5. Sound intensity is measured in ____________6. Sounds waves with frequencies below 20 Hz are called [ ultrasonic / subsonic ]7. Name an organism that uses echolocation: ___________8. What is the job of the outer ear?zx9. What is the study of sound called?10. Give one example of a percussion instrument.