Formulate Goals and a Statement of Intent - Assignment Example

The aim of the experiment is to determine the frequency of the sound produced by a turning folk. This is done by determining condition for resonance using tube of adjustable length. Introduction Turning fork can be set to vibrate and sound can be heard which may compose of different frequency. The frequency maybe one or more, depending on the type of tube. The tube maybe closed or opened. Sound is always reflected in a closed tube hence resonance is always created in the air between the turning fork and the surface.

This resonance is detected through change in sound that is heard. Water can be used as a reflecting surface and the tube confining the air above the surface to enhance the effect of resonance in the experiment done. A wave will undergo reflection whenever it hits the surface between the two regions in which the velocity of the wave differs. The velocity of sound in air is different from the velocity of sound within the tube; this is because of the walls of the tube. A closed tube resonate if the length of the tube is ¼ the wavelength.

The tube can also resonate if the wavelength is 3/4, 5/4, and 7/4. Since the air that is in contact with the water surface cannot move. The length of air column must be equivalent to the odd multiple of ¼ wavelength of the sound wave. However, the distance between two adjacent water levels, which correspond to resonance will be exactly ½ of wavelength as shown in the figure below. The resonance gives an easy way vary the length of the closed tube.The difference between one resonance and the next resonance is always ½ of the wavelength, it does not matter which resonance is being compared.(h1- h 2) = λ/2………………………………………………. (1)The velocity of the wave is now calculated by using wavelength and frequency of the wave using the formula below.

V=f λ ……………………………………………………….. (2)Figure 1Combining equation 1 and 2 gives the frequency of a turning fork whose sound resonates along the tube. The equation derived is given below.V = f λ = f (2h n+1 – ho) = f2 (Δ h)…………………………………………………………. (3)In this case the velocity is given by the following expression.V = (331.7m/s + (0.6m/s/O c) T) Experimental procedure and equipment Equipment used1.

Resonance tube2. 2 turning folk3. Striker4. PASCO sound sensor ProcedureThe temperature of air in the room was measured and recorded.Holding a vibrating turning fork at a fixed location the height of the water level was varied. This was used to record the height h when resonance occurs. Notation was made regarding the relative pitch of sound. Two frequencies was usedThe last two steps were repeated using a different turning folk. Collected data Resonance tubeT = 20.

20CHeight of the resonance (cm)Frequency of the folk15.5512241024 Data analysisCalculating the speed of soundV=f λV = 15.5 * 5127936m/sCombining equation 2 and 1 V = (331.7m/s + (0.6m/s/O c) T) = (331.7m/s + (0.6m/s)*293.5K = 97530.05m/sTaking the difference in height0.24-0.155= 0.085m0.085m /2=0.0425mGetting frequency97530.05m/s= f*2*0.0425 = 1147412HzDifferent frequency vibrate at more than one frequency, this can be seen from the two frequency measured.

First frequency = 512Second frequency =1024Although the folk vibrate at different frequency the frequency were related; the first frequency is half the second frequency. This is because the height was reduced by half. The frequency measured was also consistent with the turning folk and the sound sensor measurement. Resonance is a phenomenon in which an oscillating object eg folk if tapped due to the frequency of the wave produces a musical note.Closed tube sound waves are always reflected back and forth inside the tube.

The length of the tube is the correct multiple of λ; the bouncing wave can resonate in the tube. Standing wave will be produced in the tube sending waves of known frequency. Increasing the length of the tube increases the loudness (resonating). Discussion A wave occurs when a string or air is set into vibration, the wave have velocity and frequency for it to travel. When two waves travel in two opposite direction, the interference between the two creates a phenomenon known as standing wave.

The wave has got both nodes and antinodes. It is the resonance of the wave that is vibrating the air; this creates musical sounds which are mostly used in instruments.