1. Sound Mrs. Pursley Chapter 21

2. What type of wave is Sound ???  Sound is a MECHANICAL wave.  Sound is also a LONGITUDINAL wave.  Draw an example of this wave below. lllllll l l l l llllll l l l l l l llllllll l l l l l l lllllll l l l l llllll l l l l l l llllllll l l l l l l Label the compressions and rarefactions

3. Examples of sound waves How sound waves travel  http://www.fearofphysics.com/Sound/dist. html http://www.fearofphysics.com/Sound/dist. html http://www.fearofphysics.com/Sound/dist. html  http://www.fearofphysics.com/Sound/dist _hear.html http://www.fearofphysics.com/Sound/dist _hear.html http://www.fearofphysics.com/Sound/dist _hear.html  http://www.engineeringinteract.org/resour ces/oceanodyssey/flash/concepts/source sofsound.htm http://www.engineeringinteract.org/resour ces/oceanodyssey/flash/concepts/source sofsound.htm http://www.engineeringinteract.org/resour ces/oceanodyssey/flash/concepts/source sofsound.htm

4. How is sound Made  Sound is made from VIBRATIONS. Sound travels the fastest in a SOLID and the slowest in a GAS  Mechanical waves need a MEDIUM in order to travel. Can sound travel in space?___________ b/c ____________. http://www.harcourtschool.com/activity/scie nce_up_close/521/deploy/interface.html http://www.harcourtschool.com/activity/scie nce_up_close/521/deploy/interface.html

5. Properties of Sound  PITCH is the highness or lowness of a sound  In order to change the pitch of a sound the FREQUENCY of a wave needs to be changed. (That means you ADD MORE waves or TAKE AWAY waves or change the WAVELENGTH. )  The more waves you have the HIGHER the pitch  The less waves you have the LOWER the pitch  Frequency is measured in HERTZ.  Frequencies that are too high for people to hear are called ULTRASONIC.  Frequency affects the PITCH of a sound.

6. Pitch Continued  http://www.engineeringinteract.or g/resources/oceanodyssey/flash/ concepts/pitch.htm http://www.engineeringinteract.or g/resources/oceanodyssey/flash/ concepts/pitch.htm http://www.engineeringinteract.or g/resources/oceanodyssey/flash/ concepts/pitch.htm  http://www.engineeringinteract.org/resour ces/oceanodyssey/flash/tests/questions/p itch.htm http://www.engineeringinteract.org/resour ces/oceanodyssey/flash/tests/questions/p itch.htm http://www.engineeringinteract.org/resour ces/oceanodyssey/flash/tests/questions/p itch.htm

7. DOPPLER EFFECT  The apparent change in PITCH of a sound caused by the motion of either the listener or the source of the sound.  As an object moves toward you, the sound waves get CLOSER TOGETHER and the pitch of the sound is HIGH.  As an object moves away from you, the sound waves get FURTHER APART and  The pitch sounds LOWER.

8. Doppler Effect  http://www.wfu.edu/physics/demolabs/de mos/3/3b/3B40xx.html http://www.wfu.edu/physics/demolabs/de mos/3/3b/3B40xx.html http://www.wfu.edu/physics/demolabs/de mos/3/3b/3B40xx.html Low pitch high pitch

9. Loudness and amplitude  To increase the LOUDNESS of a wave, you must increase its amplitude. In other words if the wave was drawn, you would make the wave TALLER  Example – look on page 610 for amplitudes and frequencies

10. Reflection of sound  A reflection of a sound is called an ECHO Animals such as bats use ECHOLOCATION to find food and other objects  http://www.fathom.com/course/21701775/2170 1775.html http://www.fathom.com/course/21701775/2170 1775.html http://www.fathom.com/course/21701775/2170 1775.html  http://www.acoustics.salford.ac.uk/schools/less on3/lesson1p4.htm http://www.acoustics.salford.ac.uk/schools/less on3/lesson1p4.htm http://www.acoustics.salford.ac.uk/schools/less on3/lesson1p4.htm (use slides 2-3 only) (use slides 2-3 only)

11. Sonic Boom  A sonic boom is created when a jet overcomes or goes FASTER than the speed of sound.

12. Resonance  Resonance occurs when one object that is vibrating causes another object to Vibrate. An example of this would be a tuning fork and guitar strings. If I strike the tuning fork and hold it close to qa guitar, the strings would also vibrate.

13. Noise and music  Just because you do not like the Rhythm of a song does not make it NOISE  Noise is a RANDOM MIX of frequencies  Music is SOUND waves with a repeated pattern

14. Review  Refraction, reflection and diffraction  http://www.acoustics.salford.ac.uk/school s/lesson3/lesson1p5.htm http://www.acoustics.salford.ac.uk/school s/lesson3/lesson1p5.htm http://www.acoustics.salford.ac.uk/school s/lesson3/lesson1p5.htm  (page 4-7)