Speed of sound

In laboratory nine the physical science class synched clapping boards to echo arrivals to generate data that leads to measuring the speed of sound. The class began with a determination of the dry bulb (28°C) and wet bulb (26°C) temperatures. Using the tables from section 8.1, the relative humidity was determined to be 85%. The class was later instructed to use WolframAlpha to determine the theoretic speed of sound in air. The value that I learned long years ago in school is about 20 m/s slower than the usual sound speed on Pohnpei, due primarily to temperature. On a crisp fall day in the midwestern United States the text book value of 330 m/s is fairly accurate. On Pohnpei sound never moves that slowly.

Corazon measures the echo flight distance in the 8:00 lab section using a GPS receiver. The receiver was quoting an accuracy of 4 meters. Almost all of the error is in the clapping, not the distance measurement.

Leilani claps the clapper boards while Loioshi times ten seconds. Norma counts off the number of board claps during the ten seconds.

Loioshi tries her hand at synchronizing to the echoes while Corazon times.

Norma takes a turn at timing the board claps. Evelyn looks on, Senioleen and Kioleen to her left.

Combining the data for both classes yielded a slope of 341 m/s, only 2% below the temperature and humidity adjusted value. Using the LINEST function to force the y-intercept to zero results in a slope of 323 m/s, only 6% below the expected result for the sound speed. Given the basic nature of the equipment used - boards being banged in synch with an echo by hand and ear, these results are excellent.
Posted by Picasa

Popular posts from this blog

Box and whisker plots in Google Sheets

Creating histograms with Google Sheets

Traditional food dishes of Micronesia