1. Physics 2225 Minilab 1: A Look at Sound Purpose Visualize the wavelike nature of sound by using a sound-to-voltage transducer (otherwise known as a microphone….). Measure the speed of sound in a variety of ways.

2. Physics 2225 Minilab 1: A Look at Sound Activity I: The Nature of Sound Sound  Microphone (converts sound to electric voltage) Pasco 750 Interface Computer/Data Studio : Used as an oscilloscope

3. Physics 2225 Minilab 1: A Look at Sound Data Studio as a 1-Channel Oscilloscope adjust horizontal axis by clicking on black triangles adjust vertical axis by clicking on black triangles adjust trigger level here by sliding triangle up or down

4. Physics 2225 Minilab 1: A Look at Sound T (period) 1ms

5. Physics 2225 Minilab 1: A Look at Sound Activity II: Standing Waves and the Speed of Sound tuning fork Procedure:  Adjust pipe location until the sound from the tuning fork is amplified.  Measure L as shown on the left.  Think about the relationship between the wavelength  and the length L.  Determine wavelength   Calculate the speed of sound using L Note: f is written on the tuning fork.

6. Physics 2225 Minilab 1: A Look at Sound Review: Uncertainty from Repeated Measurements (e.g., Q8)  Calculate the average speed of sound from several measurements.  Determine the standard deviation  v  Calculate the standard deviation of the mean:

7. Physics 2225 Minilab 1: A Look at Sound Activity III: Measuring the Speed of Sound with Microphones table stand Microphone 2 (plugged into port B !!) Microphone 1 (plugged into port A !!) Clap ! d

8. Physics 2225 Minilab 1: A Look at Sound How We Measure “t” The basic idea:  Sound first hits microphone 1  Triggers the oscilloscope  Measurements on both microphones are started simultaneously and displayed in Data Studio (acts now as a 2- Channel oscilloscope).  Sound pattern is seen on Channel A first, then Channel B.  Time shift in sound pattern (Ch A versus Ch B) is “t”.

9. Physics 2225 Minilab 1: A Look at Sound Data Studio as a 2-Channel Oscilloscope adjust horizontal axis to 0.5 ms/div adjust vertical axis of Channel A or B. Make Ch. A 5 Volts/div Make Ch. B 2 Volts/div Suggested values: Please play with these adjustments as needed.

10. Physics 2225 Minilab 1: A Look at Sound After a Successful Clap … Identify Repeat Pattern t It may require several clap attempts before you can reliably recognize the same pattern in Channel B as in Channel A.

11. Physics 2225 Minilab 1: A Look at Sound Activity IV: Measuring the Speed of Sound with an Echo Table Stand Microphone 1 (plugged into port A !!) Clap ! d Hollow cardboard tube

12. Physics 2225 Minilab 1: A Look at Sound First passage Echo Identify a repeated pattern…you may need several attempts t

13. Physics 2225 Minilab 1: A Look at Sound % Difference (e.g., Q 13)

14. Physics 2225 Minilab 1: A Look at Sound Important  In the lab manual the data studio activities are called: “Sound1.ds”, “Sound2.ds”, “Sound3.ds” The actual files are called: “A Look at Sound 1.ds” ….etc…  Whenever you launch a new Data Studio file, you must first close all other existing Data Studio files. Then launch the new one. Still, sometimes the “Start Button” won’t work. If that happens, close the file and launch it again.