Physics Chapter 16

MiniLab: Pitch and Medium

 

Equipment

5 identical bottles (soda-pop bottles work well)

wooden stick

 

Objective

During this minilab you will investigate the relationship between the pitch of a sound and the medium through which it travels.

 

Procedure and Observations

1. Fill each bottle with a different amount of water.

 

 

2. Tap on the side of each bottle with the stick. Which bottle had the highest pitch? Which had the lowest?

 

3. Blow across the top of each bottle. Which bottle had the highest pitch? Which had the lowest?

 

4. Adjust the water levels in the bottles so you can tap out a simple tune for your classmates.

 

Interpretation

1. What vibrated when you tapped the bottles? How did the amount of material affect the pitch?

2. In what way did the pitch vary when you blew across the top of the bottles?

3. What was vibrating when you blew across the tops of the bottles?

4. What fraction of a wavelength is the column of air in the bottle?

5. As the length of the air column gets longer, what happens to the frequency?

6. Does the pitch become higher as the frequency increases or as the wavelength increases?