An experiment to find the acoustic impedance of paraffin and water
Abstract
The speed of sound through paraffin and water was measured, and came close to the generally expected value. The speed in was calculated as 1458.36±16.2ms^(-1) in water and 1212±23.7ms^(-1) in paraffin. Then the density of these two liquids was measured, and combined with the speed of sound to find the acoustic impedance. . The acoustic impedance of water was 1575±29kgm^(-2) s^(-1) and the acoustic impedance of paraffin was 1066.6±32kgm^(-2) s^(-1) . To check that these values were correct the reflection coefficient of a boundary between paraffin and water was calculated using the acoustic impedances of the liquid, then found by comparing the amplitudes of the transmitted and reflected waves. The values were 0.192±0.02 and 0.13±0.02, which are close enough to each other to validate that the acoustic impedances measured are quite accurate.
introduction
When a wave travelling through a material hits a boundary with another material it is affected by the boundary and some of it will be reflected back. How much is reflected back depends on the acoustic impedance of the materials at the boundary.
This experiment will find, experimentally, the acoustic impedance of paraffin and water. This will be done by measuring the density of these materials and the speed of sound through them. The values obtained for the acoustic impedance will be used to find the reflection coefficient of the boundary. This value will be checked by measuring the amplitude of reflected waves off a boundary and then finding the reflection coefficient from these measurements. If the two values obtained for the reflection coefficient are close, then the acoustic impedance measurement...
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...for the acoustic impedance of paraffin and water, the reflection coefficient between paraffin and water was calculated to be 0.192±0.02 . By observing the reflected amplitude of the waves from the boundary, the reflection coefficient was again calculated; but in this calculation its value was 0.13±0.02. These two values are very nearly within each other’s error bounds, but there is still a slight discrepancy. This discrepancy is hard to explain, but it could be due to changes in temperatures in the room or just larger errors involved than was thought during the experiment. The second calculation for the reflection coefficient is probably closer to the true value because less measurements were taken for its calculation.
Works Cited
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For this solution, 5 mL of the solution with 2.5 mL of AMV was placed in the cuvette. The cuvette was placed inside of spectrophotometer and the amount of absorbance was recorded. This procedure that involves a solution with a known concentration was repeated for the concentrations:1.0x10-4 M,5.0x10-5 M,2.0x10-5M, and1.0x10-5M.A unknown solution absorbance was measured by putting 5 mL of unknown solution with 2.5 mL AMV in a cuvette. The cuvette was placed in the spectrophotometer and the amount of absorbance was recorded. The procedure that deals with the unknown solution was repeated 2 more times with the same solution and the same amount of solution and AMV.
The purpose of this experiment was to determine whether if the sound is affected when it travels through different length pipes. The method used to do this experiment was created by using 5 different PVC pipes in the lengths of 10, 20, 30, 40, and 50 centimeters. Then, using a tuning fork, sound will be produced on one end of the PVC pipe and measured with a decimeter on the other end. This experiment was recorded using 5 trials for each independent level and the average decibels (dB) for each pipe length were recorded.
note. Most notes have reverb on them to give a transient to the sound to make it sound wet and
Ultrasound is sound waves that have a frequency above human audible. (Ultrasound Physics and Instrument 111). With a shorter wavelength than audible sound, these waves can be directed into a narrow beam that is used in imaging soft tissues. As with audible sound waves, ultrasound waves must have a medium in which to travel and are subject to interference. In addition, much like light rays, they can be reflected, refracted, and focused.
As said above, both light and sound waves have to do with interference. In sound, interference affects both the loudness and amplitude. When two waves’ crests overlap, the amplitude increases. The same is true with the troughs of the waves, which decrease the amplitude.
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After finishing the trials, our group subtracted the mass of the glassware without water from the mass of the glassware with water in order to find the mass of the water in grams. Then, we divided the mass of the water by the density(g/cm^3) of the water in order to find the volume (mL). An example calculation from the 5.00mL pipet is: (4.9285mL+4.8839mL+4.9367mL+4.9265mL+4.9134mL)/5 = 4.9178. In most cases, the temperature of the water was around 23 degrees celsius, making the density about .998408 g/cm^3 for many of the trials. The densities we used were found online. The next calculations we performed were to determine the average volume of the water in each person’s five trials by adding up all of the volumes(mL) and dividing that number by five. Using the average volume, we then calculated the
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The Scholar: I think that's more a function of sound wave vibration than anything else.
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Sound waves take the form of compressional waves and are caused by vibrations. Sound waves are distinguished by their speed, pitch, loudness and quality (timbre) (Lapp, 2003). There are a few parts of sound waves that we should be familiar with to better be able to understand the physics of music. The crest is the highest point of a wave, while the trough is the lowest. The wavelength of a wave is the distance between two adjacent parts of a wave, like from crest to crest, or from trough to trough....
Sound is essentially a wave produced by a vibrating source. This compression and rarefaction of matter will transfer to the surrounding particles, for instance air molecules. Rhythmic variations in air pressure are therefore created which are detected by the ear and perceived as sound. The frequency of a sound wave is the number of these oscillations that passes through a given point each second. It is the compression of the medium particles that actually constitute a sound wave, and which classifies it as longitudinal. As opposed to transverse waves (eg. light waves), in which case the particles move perpendicular to the direction of the wave movement, the medium particles are moving in the same or opposite direction as the wave (Russell, D. A., 1998).
waves are further divided into two groups or bands such as very low frequency (