Wave speed is dependent upon the medium through which the wave is traveling. By changing a medium you can change the wave speed. Usually any change in velocity will be balanced by an equivalent change in the wavelength - this phenomena is called refraction. Our "string medium" can be altered by changing the tension under which it is placed. Since our apparatus regulates each string's fundamental wavelength, the greater the tension, the faster the wave travels, and therefore the higher the frequency of that string.
The new speed of the wave depends on not only the tension but the mass per unit length of the string; a quantity referred to as its linear mass density. The mathematical relationship of wave speed, tension, and linear mass density is: In this lab you will be tuning five strings (of different linear density) to the same pitch(frequency). Since the strings have the same fundamental wavelength, this means that waves traveling along each string must have the same wave speed. By measuring the tension and linear density of each string we will be able to determine the velocity of the waves along each string. Then by measuring fundamental wavelength we can determine the frequency at which the string is vibrating.
Before you begin, open the spreadsheet entitled 1-WaveTensionLab.xls in your period folder and resave it as LastnameLastname-WavetensionLab.xls so that you can immediately begin recording and saving your data. |