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Do Now. In an open tube resonator, there is a pressure ________ at both ends. In a close tube resonator, there is a pressure _________ at the closed end and a pressure ________ at the open end. node. a nti-node. node. ***Note that this is the opposite of standing wave formations
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Do Now • In an open tube resonator, there is a pressure ________ at both ends. • In a close tube resonator, there is a pressure _________ at the closed end and a pressure ________ at the open end. node anti-node node ***Note that this is the opposite of standing wave formations which represent air displacement.
DO NOW • The diagram above depicts the standing wave pattern of the fundamental frequency or __________ harmonic of a _________ tube resonator. • The wavelength is equal to _________ times the length of the tube. L first closed four
Drawing Standing waves • The basis for drawing the standing wave patterns for air columns is that vibrational anti-nodes will be present at any open end and vibrational nodes will be present at any closed end. For a tube closed at one end… = nodes = anti-nodes In general, for the nth harmonic of a closed tube… Where n = 1,3,5…(odd)
Drawing Standing waves • The basis for drawing the standing wave patterns for air columns is that vibrational anti-nodes will be present at any open end and vibrational nodes will be present at any closed end. For a tube open at both ends… = nodes = anti-nodes In general, for an nth harmonic of an open tube… Where n = 1,2,3,4… (all integers)
Do NOW • Take out your homework… • For a closed pipe… • The first harmonic has __________ of a wavelength • The third harmonic has __________ of a wavelength • The fifth harmonic has _________ of a wavelength • The seventh harmonic has _________ of a wavelength • The nineth harmonic has __________ of a wavelength. 1/4 3/4 5/4 7/4 9/4
REview • One person reads the question on the green side of the card ("who has: material a wave travels through"?), • The answer is on the purple side of someone else's card and they respond ("I have: medium")
Do Now • Take out a writing utensil, your notecard (if you have it), and a calculator. Answer the following question on your DO NOW… • What grade do you expect to get on the practice test today? • What grade to you want to get on the test on Monday?
C D D C D 1.35 m 880 Hz; .0011 s 1500m/s; 480 m 60 Hz; 1.50 m Yes; No 1.24 m; 353.4 m/s; .62 m, 570 Hz; .41 m, 855 Hz 43. 2.74 m; 125 Hz; .91 m, 375 Hz; .55 m, 625 Hz 44. 1160 Hz ; 866 Hz Nodes Incident C C B B A C B D C C D B A C • Medium • Mechanical • Transverse • Longitudinal • Interface • Period • Electromagnetic • Frequency; Hertz • Reflection, refraction, or diffraction • Diffraction • Ray • Wavelength; λ • Electromagnetic • Speed • Source • Superposition or Interference