Group # 2 2E-Pharmacy Members: BARRO, Anne Catherine BATOL, Patricia Anne BAUTISTA, Paula CANLAS, Jenica CATABONA, Nikki. *CEBRIAN, Lizbeth Aura
Date Performed:February Performed:Febru ary 4, 2013 Date Submitted: February 11, 2013
EXPERIMENT 6 – RESONANCE AND THE SPEED OF SOUND Abstract: Sound is a wave created by vibrating objects, travelling through a medium and moving from one location to another. In this experiment, a fluid medium was used to determine the measure of the speed of sound. The procedures of the experiment are as follows: First, a tuning fork was vibrated using a rubber mallet. Then, it was placed in a graduated cylinder which is partially filled with water in such a way that it had to be a specific amount, otherwise the tuning fork will not make a sound. When the frequency of the tuning fork is high, the wavelength must be low. Finally, the speed of sound obtained in this experiment was then compared to the actual speed of sound which is 34550 cm/sec. Question & Answer: 1. Through what fraction of a vibration has the prong of a tuning fork moved while the sound travelled down to the water surface inside the pipe and reflected back up to the fork again? The prong of the tuning fork vibrated ½ of a cycle, because the sound wave travelled travelled ¼ of a wave down and ¼ of a wave up. 2. What is the approximate wavelength of the fundamental frequency of a closed tube 35.0 cm long if the tube has a diameter of 4.000 cm? FORMULA: λ= 4[L + 0.3 D] λ= 4[35.0 + 0.3 (4.000)] λ= 4[35.0 + 1.200] λ= 4[36.2] λ= 144.8 144.8 cm λ= 145 cm 3. A tuning fork of frequency 384 Hz exhibits resonance with a closed tube 20.0 cm long and 4.000 cm in diameter. What is the speed of the sound wave? Use the formula: λ= 4 [L + 0.3 D], to get λ. λ= 4 [20.0 + 0.3 (4.000)] λ= 4 [20.0 + 1.200]
λ= 4 [21] λ= 84 cm Then, use the formula: V =λf to get the speed of sound. V= 84 x 384 V= 32300 V= 32000 cm/sec
