Download presentation
Presentation is loading. Please wait.
Published byEzra Lee Modified over 9 years ago
1
Physics Chapter 5, Section 4 Sounds from Vibrating Air
2
Mar 14, 2012 HW: 5.4 PTG p 526 #1, 4-6, Due Tuesday Learning Objective Explain how sound is produced by longitudinal compression waves Write a conclusion that includes IV, DV, evidence, and the big idea Success Criteria Identify standing waves in different kinds of air-filled tubes Observe how pitch changes with the length of the tube Observe the effect of closing one end of the tube on the pitch of the sound Observe sound bending around corners and spreading Relate observations of pitch to drawings of standing waves Organize observations to find a pattern Do Now Write LO and SC on new left page p 518 WDYS/WDYT Agenda Do Now Investigation 5.4 Summary
3
Investigation 5.4 pg. 519-520 Part A (groups) 1-3 - with straws 4, 5 with test tubes Part B 1 - Class demo 2 - with group Part C In groups Set up Notebook Ok with Spencer Set up Notebook Ok with Spencer Set up Notebook Ok with Spencer
4
Mar 16, 2012 HW: HW: 5.4 PTG p 526 #1, 4-6, Due Tuesday Learning Objective Explain how sound is produced by longitudinal compression waves Write a conclusion that includes IV, DV, evidence, and the big idea Success Criteria Identify standing waves in different kinds of air-filled tubes Observe how pitch changes with the length of the tube Observe the effect of closing one end of the tube on the pitch of the sound Observe sound bending around corners and spreading Relate observations of pitch to drawings of standing waves Organize observations to find a pattern Do Now How did closing the end of the tube change the sound? Why do you think this happened? Agenda Do Now Physics Talk Reflection Quiz
5
Physics Talk 5.4 What kind of waves does sound make? How does this relate to springs? Compressional (longitudinal) waves
6
Physics Talk 5.4 What was the medium the sound traveled through? The air in the straw or tube
7
Physics Talk 5.4 How do these relate to the standing waves created by the stringed instrument? Air molecules cannot vibrate at the bottom of the test tube, so this is a node of the wave The open end of the test tube provides the wave’s amplitude The vibration of the air at this end, is the sound you hear This is the antinode of the wave
8
Physics Talk 5.4 What is diffraction? The ability of sound waves to spread out or change direction as they emerge from an opening This is why you can hear someone talking around a corner Megaphone (cheerleader thing)
9
Physics Talk 5.4 The top show a large amount of diffraction, when the opening is smaller The bottom shows a small amount of diffraction, since the opening is larger
10
Physics Talk 5.4 How do megaphones work? A megaphone increases the diffraction of sound, due to the small opening you yell into The best opening size depends on the sound being produced
11
Vibrating Columns of Air
12
Physics Talk How does changing wavelength effect frequency? When keeping a constant wave speed, increasing the wavelength will decrease the frequency - causing a lower pitch
13
Physics Talk 5.4 Open tube wavelength Closed tube wavelength Half of the wavelength will fit The wavelength is 2x the length of the tube One quarter of the wavelength will fit The wavelength is 4x the length of the tube
14
Physics Talk 5.4 Why does the closed straw have a lower pitch? Why does the open straw have a higher pitch? The wavelength is longer (4x), meaning the frequency is lower The wavelength is shorter (2x), meaning the frequency is higher
15
Essential Questions pg. 525 What does it mean? How do you know? Why should you care? LO and SC reflection on left side pages.
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.