Maxim Gurevich
Doppler Effect Physics IA
Introduction
The Doppler Effect is a wave phenomenon that can be heard every day. It affects different sound differently depending on their sources’ speed relative to the observer. I noticed this when I observed that if the source moves too slowly, the effect is less apparent. I wanted to explore this situation, and to fulfill my curiosity, I used a sound emitter traveling in a circle. I asked this question: “How does the angular velocity of a sound emitter traveling in a circle affect the range of frequencies heard by a fixed observer?” Background The Doppler Effect is the shift in apparent frequency for an observer when a source of waves is moving towards or away from the observer, causing the pressure
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Motor Power Seconds Per Revolution of Sound Source (sec +/- .01 sec) Average Uncer. Of Ave.
% trial 1 trial 2 trial 3 trial 4 trial 5 trial 6 trial 7 trial 8 trial 9 (sec +/- .09 sec)
10 1.72 1.75 1.66 1.82 1.82 1.78 1.76 1.75 1.72 1.75 0.04
20 0.51 0.52 0.52 0.55 0.55 0.57 0.58 0.56 0.6 0.55 0.045
30 0.35 0.35 0.33 0.34 0.35 0.36 0.35 0.36 0.35 0.35 0.015
40 0.25 0.28 0.25 0.27 0.27 0.26 0.25 0.24 0.28 0.26 0.02
50 0.21 0.23 0.22 0.2 0.2 0.22 0.21 0.2 0.25 0.22 0.025
60 0.19 0.19 0.18 0.19 0.2 0.2 0.19 0.17 0.2 0.19 0.015
70 0.19 0.2 0.19 0.18 0.21 0.18 0.18 0.17 0.17 0.19 0.02
80 0.22 0.19 0.22 0.19 0.19 0.2 0.19 0.19 0.22 0.2 0.015
90 0.17 0.19 0.2 0.19 0.19 0.17 0.17 0.19 0.19 0.18 0.015 Ave. = +/- .023 sec
speed # Seconds per Revolution (sec+/-.023 sec) Angular velocity (2π / sec per rev) (+/-.023 rad/sec) Min frequency (Hz+/-.01Hz) Max frequency (Hz+/-.01Hz) Ave. (Hz+/-0.2Hz) Range (max-min)
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Possibly the largest source of error is in the structure of spinning mechanism. It is likely that the materials used to build the spinner, namely plastic and a small motor, lose accuracy and consistency at high speeds, shaking due to slight imbalances between the sound emitter and the counter weight. This could cause unexpected fluctuations in the frequency of the sound received by the microphone. Additionally, even though the angular velocity was carefully measured by hand with a stopwatch, there is a slight difference between the recorded rpm of the rotating platform and the actual rpm of the platform. The relatively small radius of the path of the sound emitter limited the range of the experiment. A larger radius might have yielded a larger range of data points, due to the greater velocity resulting from the longer circumference that the sound emitter must travel per revolution. With the current setup however, fluctuations in volume are insignificant due to the small change in distance between the sound emitter and the microphone. An improved version of this lab would include stronger and lighter materials as well as a lighter sound emitter to minimize the shaking of the set up at high rpm rates. A smarter motor, which detects, selects, and maintains its own rpm would be more consistent
There were no significant error factors that may have affected the arrangement of the lab experiment. Everything went smoothly with relative ease.
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.
In this experiment, there were several objectives. First, this lab was designed to determine the difference, if any, between the densities of Coke and Diet Coke. It was designed to evaluate the accuracy and precision of several lab equipment measurements. This lab was also designed to be an introduction to the LabQuest Data and the Logger Pro data analysis database. Random, systematic, and gross errors are errors made during experiments that can have significant effects to the results. Random errors do not really have a specific cause, but still causes a few of the measurements to either be a little high or a little low. Systematic errors occur when there are limitations or mistakes on lab equipment or lab procedures. These kinds of errors cause measurements to be either be always high or always low. The last kind of error is gross errors. Gross errors occur when machines or equipment fail completely. However, gross errors usually occur due to a personal mistake. For this experiment, the number of significant figures is very important and depends on the equipment being used. When using the volumetric pipette and burette, the measurements are rounded to the hundredth place while in a graduated cylinder, it is rounded to the tenth place.
This chapter provides some insight into pulse wave analysis and its relation to arterial diseases. The shape of the arterial pulse wave is an augmentation of the forward traveling wave with the reflected wave. The amount of wave reflection is dependent on the arterial wall properties such as arterial stiffness and is expressed in terms of Augmentation Index. This approach has been studied extensively using various measuring techniques, all of which have respective advantages and disadvantages. The purpose of PWA can be seen in the section describing the medical conditions that affect the wave shape. The discussion is included to assist the reader in understanding the purpose of pulse wave analysis.
Possible sources of error in this experiment include the inaccuracy of measurements, as correct measurements are vital for the experiment.
At any point in the air near the source of sound, the molecules are moving backwards and forwards, and the air pressure varies up and down by very small amounts. The number of vibrations per second is called the frequency which is measured in cycles per second or Hertz (Hz). The pitch of a note is almost entirely determined by the frequency: high frequency for high pitch and low for low .
For examining the influence of age and gender on the Stroop effect, the experimenter adopted the Stroop paradigm. In Stroop paradigm there are three: neutral or control, congruent and incongruent groups. Neutral / control group will receive stimuli in which only the text or colors are presented (van Maanen L, van Rijn H& Borst JP, 2009). When the color of the word and the text of the word refer to the same color (for example the word "red" printed in red) is a congruent stimulus. In Incongruent stimulus, the color of the word and color of the text differ (for example the word "red" printed in blue).
All the issues, raised by the author, are due to the fact, that the author decided not to use α', but α as an angle, that is equal to π/2, in order to define transverse Doppler effect. It is obvious, that α is the angle b...
Since the origin of crime, criminals have attempted to evade justice. This is evident when criminals tamper with evidence, take hostages, and attempt to flee the scene. With the introduction of the automobile, fleeing the crime scene has become dramatically simpler. As technology increases, these automobiles are safer, handle better, and go faster than ever before. The police therefore are forced into pursuit with their own automobiles, endangering the lives of officers and civilians. So the question becomes, how can pursuits be avoided and then when they do occur, how can they be shortened?
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.
Sound is defined as areas of high and low pressure that move outward to form a longitudinal wave. The amplitude and pitch of the sound is dependent on the source and amount of energy produced. Sound is produced by vibrating objects, the vibrations cause disturbances in the surrounding air molecules. When the vibrating object moves outward it causes the air molecules around it to compress and create a high pressure region. As the object moves inward the air molecules expand and create a low pressure region. The high pressure regions are called compressions and the low pressure regions rarefactions. The equation of sound waves is speed = wavelength x frequency or v = f x .
The Scholar: I think that's more a function of sound wave vibration than anything else.
Signal detection theory is introduced by mathematicians and engineer in 1950 . It started to evolve from the developing electronics communication.
In recent years, several studies have been conducted surrounding the concept of Mozart enhancing intelligence. Studies conducted regarding this phenomenon have dubbed it the ‘Mozart effect’. The theory has been popularized by the media, with businesses, leaping at the opportunity to sell intellect in the form of Mozart products. Consequently, the claim ‘listening to Mozart makes babies smarter’ became an adopted belief. Thorough research into the Mozart effect, lead to the hypothesis that there is inadequate evidence to support this claim. This literature review intends to support the hypothesis through critically analysing various articles and presenting arguments to disprove the claim. Literature founded achieves the hypothesis through expressing a lack of evidence focusing on an infant age group; as well as being inadequate in depicting Mozart’s ability to enhance intelligence through examining only spatial intelligence and the absence of evidence supporting long term intellectual developments. Throughout this review research, mostly in the form of studies is presented to successfully demonstrate these points and disprove the claim.
There is also the potential of human error within this experiment for example finding the meniscus is important to get an accurate amount using the graduated pipettes and burettes. There is a possibility that at one point in the experiment a chemical was measured inaccurately affecting the results. To resolve this, the experiment should have been repeated three times.