Lab 5- Sound

LAB 5- SOUND

Abstract:

In lab five, we measured the speed of sound in air by three different methods. These experiments proved that sound is a logitudinal wave in which the particles in the air oscillate parallel the the direction of travel of the wave, resulting in alternating compressions and rarefactions in the medium through which the wave travels. The velocity of these waves only depend upon the properties of the medium and not upon the frequency of the wave. Additionally, if the wave is traveling through a gaseous substance, the velocity depends only on the temperature which is measured in Kelvins. In a direct measurement of sound a sharp sound was produced near a storage oscilloscope where the sound was reflected from a spherical mirror sending the sound waves to the end of the corridor. The sounds waves travel to the wall and back due to an echo. In the resonating of air columns, a vibrating fork (which determines the frequency) and column of water are used to determine the wavelength for one cycle of vibration. And finally, using an ultrasound, two transducers are used to produce sound with a frequency of 40kHz. The ultrasound from the transmitter is picked up by second transducer and converts the ultrasound back to electrical oscillations which are displayed on the other channel of the oscilloscope.

A longitudinal or compression wave causes oscillations in the medium parallel to the wave’s direction of travel. A transverse or light wave causes oscillations in the medium perpendicular to the wave’s direction of travel. This wave looks like a sine wave. A traveling wave moves with a constant velocity in a medium, this velocity depends only on properties of the medium and is constant for a given type of wave. In the air on Earth, traveling waves follow the formula: v = 20.1 √(TK) m/s .

Pitch is described as the sensation of a frequency. A high pitch sound corresponds to a high frequency sound wave and a low pitch sound corresponds to a low...