Play Those Pipes Again, Sam

Purpose: This activity will provide students with the experience of listening to the separate frequencies of each pipe and inferring that frequencies vary according to length.

Pan Pipes are ancient musical instruments that consist of a series of different length hollow tubes called "pipes." Blowing air into the pipes makes them vibrate. Since the pipes vary in length, blowing into them will produce a variety of sounds.

Procedure

1. Cut the tubes (pipes) to varying lengths (example: 100 cm, 75 cm, 50 cm, 25 cm, 12 cm).
2. Lay the pipes on the cardboard in order, from tallest to shortest, and tape them together to hold them in place.
3. Have the students listen to the sounds of the classroom. Discuss the sounds that they hear and talk about frequency of sound.
4. Have students blow into each pipe and listen for the individual frequency.
5. Discuss with the students the sounds that they heard from the longest pipe and the shortest pipe.
6. Guide students to see a correlation between the longest pipe and the lowest frequency and the shortest pipe and the highest frequency. Explain that the column of air that is the longest has the slowest vibrating air molecules.
7. Have students write a short paragraph explaining their results.

Conclusion

1. How did the air sound in the longest pipe?
2. Why did it sound this way?
3. Would this sound be a low or a high frequency?
4. How do the various frequencies make music?

Extension

1. Brainstorm to think of other musical instruments that may produce different frequencies because of their shape, material, or source of energy used to originate the sound.
2. Make guitars out of various sized boxes or drums out of various sized cans.