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Observing the movements of vocal cords during speech : Ask a friend to raise his neck up. Stretch a chocolate wrapper across his mouth and ask him to blow air on the wrapper forcibly. Observe the changes in movement at his throat. Ask him to blow again slowly and observe the difference in movements. a) What changes do you observe in the movements at the throat on the two occasions?b) Does sound travel only in air?c) Does it travel in any other gaseous medium?d) Does sound also travel in other media like solids and liquids? |
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Answer» a) During the first trial the voice box gets tensed and produces high sound while during the second trial it is close to normal position of throat and produces lower sound. The sound produced in the above activity is due to a combination of vibrations produced in the wrapper and the vocal cord. Propagation of sound: Sound needs a medium to propagate: The sound produced by the school bell will be heard by all of us irrespective of whether we are in a room opposite to the bell or in a room at the back of the bell. Obviously, the sound produced by the school bell travels in all directions and reaches us, propagating through the air present between source of the sound and our ears. That is the air surrounding us act as a medium which allows the sound to pass through it. b) No, it will travel in other media. c) Yes, it will travel in any other gaseous medium. d) Yes, it will travel. |
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