Physics of Sound: How does length affect pitch?
Students will use a tongue depressor, xylophone, and kalimba to investigate how length affects pitch. They will record data in their Science Notebooks.[image right border]
Context for Use
Resource Type: Activities:Classroom Activity
Grade Level: Intermediate (3-5)
Description and Teaching Materials
Using a tone generator, have students stand on their tiptoes if the pitch is high and squat if the pitch is low. This will help students understand the difference between high- and low- pitched sounds. At this time, define pitch: how high or low a sound is. A connection to music and instruments could be made at this time.
1. Ask the investigable question, "How does length affect pitch?"
2. Ask students what tools they could use to find the relationship between length and pitch.
3. Show students the 3 different tools they will use: tongue depressor, xylophone (musical instrument made from a set of bars or tubes of different lengths), and kalimba (an African thumb instrument). Remind the class to respect the tools.
4. Explain to the class that they will work in pairs using each tool for 10 minutes. A bell will ring when it is time to switch tools. They will record their data and results in their Science Notebooks. If time permits, they can add other investigable questions they may have in their Notebooks.
5. Walk around the room to observe student understanding. Check drawings for any misconceptions.
6. Put materials aside for closure.
Ask again, "How does length affect pitch?" Listen to student findings and have them present their data to the class. Some students may show their data on the board or on the overhead projector. Ask, "What happens to the pitch and vibrations when the length of the sound source changes? Answer: A long object has a low pitch and vibrates slowly. A short object has a high pitch and vibrates quickly. Ask, "What are some musical instruments that make different pitches by changing the length of the sound source?" Answer: Trombone, recorder, harp, etc. Give students time to record additional information they learned from the closing discussion.