Doppler Effect

The order in which the greatest blue shift to the red shift of the five distant stars is E, D, B, C, A. The arrows in the diagram represent the speed of movement of the star, the longer the arrow the faster the movement of the star and vice versa. Furthermore, the motion of the source of light is said to be blueshifted if it is moving towards the observer, but if the source is moving away from the observer it is called redshifted (Prather p75). As a result, the star that is moving faster toward the observer will have the greatest blueshift while the star that is moving away from an observer will have the greatest redshift.

This essay will reflect my thoughts on chapter 9. In brief this chapter deals with how the ears allow us to be able to hear and process sound. When I first think of sound I think of the frequency. This makes me think of songs that I listen too in order to determine it 's a high frequency or a low frequency. I 'll be able to determine the amount of hertz that are in songs on the radio. I do feel that it would be hard to determine because most of that music is reordered, hearing people sing a cappella would be easier to determine the amount of hertz present. I know what hertz are, but I 'm still not sure how they are actually determined? Are they sounds just determined by our brain if we have unimpaired hearing. How would someone like my brother with a whole in his ear be able to determine frequency?

The purpose of this experiment is to measure the speed of sound in air and to determine the effects of frequency on the speed of sound.

-“The wave continues to travel for 0.20 s before stopping.” This sentence is wrong because period does not measure the time the medium takes to stop moving. Period is the measure of the time one particle takes to complete one vibration and start to repeat it again. We do not know if one particle will stop after one vibration.

Sound waves are nothing more than an energy transfer through a medium be it through a liquid, solid, or a gas. Sound pressure or intensity is measured on logarithmic scale in decibels dB which increases on an order of magnitude. For instance a quiet conversation would be around 30 dB and whereas the human pain threshold would be just over 100 dB. While the pitch or frequency of the sound is measured in hertz or Hz, the higher the hertz the higher the pitch of the sound and vice versa (Hildebrand, 2004).

a perceptible time between the end of your shouting and the onset of the returning wave (not sure how long, but lets say tc=0.1 s as a guess (a lot of human perception works on time scales not to far from that))

Sound is a very interesting topic that many people do not fully understand. There are lots of questions on why or why not we can hear certain things and how do we process different sounds and vibrations. The first thing that is important to know before getting into all the details is that sound is release of energy and the energy is released in the form of vibrations. Then , the vibrations will emit from whatever has made the sound in what is known as a longitudinal wave. A longitudinal wave is a wave that travels in a sing direction.

As the hearing is one of the most important ability a person can have it has a great deal of benefits. This allows an individual to hear sounds from a mechanical wave which is then transferred to stimulate the hearing organs inside the body. The mechanical wave is only able to transfer energy through a medium, the two types of waves that associate with the mechanical is both the longitudinal and the transverse wave.

That how the ear works but what about things we hear? When people speak sound travels

The sensory energies of light and vision and sound vibrate as waves passing through space. These waves result from reflected light or from changes in air pressure caused when vocal cords and other stuffs move. Generally eye and the ear identified the waves as light and sound. The waves of light and sound can describe in term of wavelength, frequency and amplitude. Wavelength is the distance from one peak of the wave to the next. Frequency is the number of complete waves or cycles that pass a given point amount of time. Amplitude is height of the wave from baseline to peak. These are shown in the Figure 3. The different wavelength, amplitude and frequency makes various sound and vision experience.

2. Explain how a sound is actually a form of energy? In what medium do sound waves travel?

The snail like shape of the cochlear effectively boosts the strength of the vibrations caused by sound, especially for low pitches. When sound waves hit the ear drum, tiny bones in the ear transmit the vibrations to the fluid of the cochlea, where they travel along a tube that winds into a spiral. The tube’s properties gradually change along its length, so the waves grow and then die away, much as an ocean wave travelling towards the shore gets taller and narrower before breaking at the beach.

Musicians know that all vibrating objects make sounds. Frequency measure how many times a string vibrates up and down. If a musician changed the length of the string, it also changed the frequency. High frequency will always equal a high pitch. When an octave is increased the frequency will double. Pythagoras discovered different sounds could be made with different weight and vibrations. Due this discovery, they also realized pitch could be controlled by the length of the string.

It is within this framework that I consider important to study the way in which sound is

The red bar on the left acts as the driving piston. If it moves in a sinusoidal manner from left to right, then the wave that is produced will be a sinusoidal wave. Since the wave is sinusoidal, the wavelength, amplitude and frequency are constant. This is seen in nature as a tuning fork, which produces a periodic sound wave. In a one dimensional tube as shown above, each particle undergoes simple harmonic motion. The volume that is contained in one wavelength also undergoes this same motion. We can represent the displacement of this volume as: