Sound Notes Lab Station Packet

1. Sound NotesLab Station Packet

2. What is sound? What are sound waves? longitudinal • A sound wave is a _____________ wave that is caused by __________ and travels through a ____________ • Quacking Duck Vibrations • What happens when you drag the wet towel down the string? • Explain why this happens. vibrations medium

3. compression rarefaction

4. How do sound waves travel? Part 1 • Sound waves travel by disturbing ___________________________, or a medium. • Most of the sounds you hear travel through air, but sound can also travel through ___________________ the particles in matter water, glass, and metal

5. String Telephone Fishing line Telephone • What does sound need in order to be transmitted? • What happens if the string hangs loose? • What happens if you hold the string? • What happens if you connect two or three string telephones together? • Compare what you heard to the string telephone. • Which telephone carried the sound the greatest?

6. How do sound waves travel? Part 2 • Sound must travel through air or some other __________ to reach your ears and be detected. • Watch Sound Travel • What happens to the flame? • Why does this happen? • Is there sound in outer space? Explain why or why not. medium

7. What Affects Pitch? Part 1 ___________is the highness or lowness of sound. Pitch Pitch is determined by the ______________ and ___________of sound waves. frequency wavelength

8. What type of pitch…high or low? *Low-pitched *High-pitched *Low frequency with long wavelengths *High frequency waves with short wavelengths

9. Pitch and Frequency Lab • What happens to the frequency and pitch of the sound the ruler makes as you extend more of it off the table edge? • Describe the motion of the ruler. The sound became lower so the frequency increased and the pitch was lower. The ruler moved up and down a greater distance when the ruler extended farther than when it was pulled back.

10. What Affects Pitch? Part 2 What is frequency? Measures how often a waves passes a fixed point! So…how could you increase pitch? Well of course…increase frequency!

11. What Affects Pitch? Part 2 Hertz (Hz) is the unit used to measure one complete waver (or cycle) per second. The note of middle C on the piano has 262 cycles per second. What is the frequency in Hertz? 262 Hz http://www.music.vt.edu/musicdictionary/textm/MiddleC.html

12. Wave Flash Cards A1 or A2 B1 or B2 C1 or C2 • Lower pitch • Long wavelength • Low frequency • higher pitch • short wavelength • high frequency • Lower pitch • Long wavelength • Low frequency

13. What makes a sound loud? • A measure of how well a sound can be heard is ____________________ • The measure of how much energy a sound wave carries is the wave’s ________________, or amplitude. • The more _________________ a wave has, the higher the amplitude. • The greater the amplitude, the ____________ the sound. The smaller the amplitude, the _____________ the sound. loudness intensity energy louder softer

14. Investigate Loudness • How did the loudness of the sound compare? 2. How is amplitude related to loudness? 3. Challenge: Using what you learned from experimenting with the rubber band, explain why swinging a drumstick harder on a drum would make a louder sound than swinging a drumstick lightly. The sound was louder at 4cm than at 1 cm. The greater the amplitude the louder the sound. Swinging a drumstick harder would make a louder sound because the drum skin would vibrate with greater amplitude.

15. How is loudness measured? How loud is too loud? • The most common unit used to express loudness is the _______________ decibel Comfortable HearingHearing Damage BeginsDamage ZoneDanger Zone Under 60 dB no more than 15 min. around 120 dB around 125 db unprotected for 70-100 db Normal breathing thunderclap Airplane takeoff Hair dryer whisper Vacuum cleaner Shotgun firing Normal conversation Garbage disposal traffic Food blender

16. Higher pitch lower pitch

17. What Causes the Doppler Effect? • The change frequency that occurs when the sound source, the observer, or both are moving is called ______________________. • Draw a picture that shows how the Doppler Effect changes the sound of the race car. Doppler Effect

18. In a few sentences, describe how the sound you hear changes as the racecar moves. • In a few sentences, describe why the frequency of the sound changes and how this change affects the pitch you hear. The racecar continually sends out sound waves. As it gets closer the sound waves catch up and are spaced closer together. As the racecar moves away the sound waves are still moving towards you; however, the waves are farther apart. When the sound waves get closer they are closer together so their frequency is higher which makes the pitch higher. As it moves away the waves are farther apart which means there is a low frequency-low pitch.

19. What affects the speed of sound? • Two main factors affect the speed of sound • ____________________ • ________________ medium temperature A sound wave makes the particles of matter move as it travels, so it moves fastest when particles are close together. steel air

20. The diver will hear the sound of a boat first because sound waves travel faster in water than in air.

21. Listen to This • Does the air or string transmit sound better? Explain. • Does the string or the wire transmit sound better? Explain. • What happens to the energy of a sound wave as it travels through different materials? The string transmits sound better than air because the sound was louder. The wire transmits sound better than the string because the sound was louder. Different materials absorb different amounts of a sound wave’s energy.

22. How do sound and matter interact? Smooth, hard • Sound waves reflect best off _______________ surfaces • A ________________ wall will absorb sound better than a _________________ wall will. And ____________ materials absorb sound better than _____________ materials. • Echoes • What materials allowed you to hear the sound in the second tube? • Why are you able to hear the sound in the second tube with these materials? • Why can’t the sound be heard the same with all of the materials? rough smooth soft hard

24. How do sound waves interact with each other? Interference • _______________ happens when two or more waves overlap to combine to form one wave • When ________________ interference occurs, waves overlap and combine to form a wave with a _________________ amplitude. This produces a sound that is ____________ than before. • When ________________ interference occurs, waves combine to form a wave with a _________________ amplitude. This produces a sound that is ____________ than before. constructive larger louder destructive smaller softer

25. Interference Videos • What happened to the amplitude of the combined wave when the two waves met? • What would this do to a sound wave? • Draw waves undergoing constructive interference. • What happened to the amplitude of the combined wave when the two waves met? • What would this do to a sound wave? • Draw waves undergoing destructive interference.

26. Sound Simulation • Describe what happens to the wave using the words amplitude, frequency and wavelength as you click from low to medium to high pitch. • Fill in the blanks: Low pitch =_____________wavelength and ___________frequency High pitch = ___________ wavelength and ____________frequency • Describe what happens to the wave using the words amplitude, frequency and wavelength. • Fill in the blanks: Loud sound = ____________ amplitude quiet sound = __________amplitude As the pitch gets higher, the frequency of the wave becomes higher and the wavelength becomes shorter. The amplitude of the wave is not affected. long low short high As the sound gets louder, the amplitude gets higher. Frequency and wavelength are not affected. high low