phys 122 lab report 6

Alondra De Horta- Reyes Melanie Bishara Experiment 6: The Oscilloscope February 14, 2017 Physics 122 LAB: Tuesday at 3:00pm-5:50pm

1. Theory: In this experiment we learned how to work with a digital oscilloscope and make different kinds and different distance of sound to record. We mainly were looking to calculate the exact speed of sound at the moment of the sound. The oscilloscope gave us most of the information in our charts by simply moving the horizontal lines to the two main highest points in the sound and pushing buttons that would give us other numbers like the V rms , except one. In our data for Period and Frequency in order to find the Period theoretical you had to multiply the Sweet Rate SW and divisions between the two highest points. For example, in our hum data the sweep rate SW was 2.00 ms/ and it was 3 divisions away from the other point. So when we multiple these two we get 6.00 ms for our period theoretical. 2. Procedure The procedures were the exact same as the lab manual with the exception of the ‘Note’ data. From the ‘note’ category we played Whitney Houston “I will always love you” as the sound. 3. Data table: A. Period and Frequency Sweep rate SW (unit of time/div) Division s (div) Period theo ( ) Period exp ( ) Frequency ( ) V rms ( ) %D of period Hum 2.00 ms/ 3 6.00 ms 6.400 ms 156.2 Hz 30.5 3 mV 7% Whistl e 200 μs 3.5 700 μs 688.0 μs 1.453 kHz 10.1 9 mV 2% Note 100 μs 4.5 450 μs 482.0 μs 2.075 kHz 11.0 0 mV 7% Tuning Fork 1 Frequency 1= 480 1.990 ms 502.5 Hz 8.82 4 mV 5% Period 1= 1/480= Tuning Fork 2 Frequency 2= 512 2.440 ms 409.8 Hz 6.46 7 mV 22% Period 2= 1/512 B. Speed of Sound Sweep Rate: 1 ms/division (units of time/div) Microphone Distance (cm) Time Delay ( ) V rms ( ) 0 0 μs N/A 10 280 μs N/A

6. Conclusion: Demonstrate understanding of the procedure (what did we do and why did we do it?) what I understand of this procedure was that in the previous experiments that we were doing, we where calculating an average estimate of the speed of the voltages and in the experiment with the help of the oscilloscope we were able to get the data of the test much more accurately and exact. The success of this experiment came out pretty good. Our data’s percent discrepancies were all around the same good percentage, like 7%, 2%, or 5%. The only one that we did get a high percent discrepancy and our experimental and theoretical results were not the same was when we tested turning fork 2. In this test we got a percent discrepancy of 22%, which is a little higher than our other ones. Considering the fact that our percent discrepancy for the turning fork 2 being a little higher than the other ones leads me to believe that our error was an inaccurate test. We may have stopped the sound waves at an inconvenient time where our waves were not as clear and we didn’t have accurate high points to calculate. In this case, in order to correct this mistake, next time we can keep running the sound until we get a semi perfect wave where we are able to get accurate points at the highest point of both waves.