Experiments with Sound and Soda Bottles

You can use your Texas Instruments graphing calculator and CBL to do some interesting experiments with sound and soda bottles. In particular, you can explore the relationship between various characteristics of a soda bottle and the pitch of sound it makes when you blow across its mouth.

Make the following measurements for a series of different soda bottles either empty or partially filled with water.

• The height of the air column in the bottle.
• The volume of the air column in the bottle. Note that you can measure the volume of a soda bottle by filling it with water and then emptying the water into a measuring cup.

• The frequency of the sound made when you blow across the mouth of the bottle.
• The period (in seconds) of the sound made when you blow across the mouth of the bottle.
• The wave length (in inches) of the sound made when you blow across the mouth of the bottle. Note that the wave length of a sound is its period multiplied by the velocity of sound. The velocity of sound at sea level and normal air pressure is roughly 1087 feet per second.

Use the usual features of your graphing calculator to look for relationships between the size of the air column (its volume or its length) and the pitch (frequency, period, wave length) of the sound made when you blow across the mouth of the bottle.

You may want to look up sound in a reference source, like the Encyclopedia Britannica to find out more about the way musical instruments and soda bottles produce sound.