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# Investigation 2 – PostLab

### ANALYZE IT

Complete the Analysis Questions in your SDR then discuss them as a class.

Note: The wavelength for each tuning fork needs to be calculated based on the length of PVC pipe that extended out of the water. Since the wavelength includes the complete standing wave from one ending node to another ending node, you must multiply the measured length by 4 to calculate the wavelength. After performing this calculation, you can then calculate the speed of sound in air for each of the frequencies tested with the tuning forks.

• Calculate the wavelength of the standing wave for each Trial by multiplying the measured length in meters by 4. Record the wavelength of the standing wave for each Trial in Table A. Use the space below for your calculations.
• Calculate: For each Trial, calculate the speed of sound produced by the standing wave using the following equation:

Speed = wavelength x frequency

• Multiply the frequency of the tuning fork by the calculated wavelength to calculate the speed of sound. Record the speed for each Trial in Table A. Use the space below for your calculations.

• Was the speed of sound in the air in the PVC pipe the same or similar for each of the three tuning forks?
• As the frequency of the tuning forks increased, how did the wavelengths of the standing waves change?
• Do you think that the speed of sound would be the same or different in another type of matter? Why?

### GET FOCUSED

Complete the Focus Questions in your SDR then discuss them as a class.

• What is the speed of sound in air?
• In the same type of matter, is the speed of sound different for different frequencies and wavelengths?
• What is the relationship between the wavelength and frequency of a standing wave and the sound it produces?