Investigating Sound: A Lesson in Length and Pitch

This activity is designed for students to explore length and pitch. Students will develop a hypothesis and test their hypothesis through exploration. Also, students will be making observations and writing a conclusion based on their investigations.

Key Concepts:

Students will learn that a long object has a low pitch and vibrates slowly.

Students will learn a short object has a high pitch and vibrates quickly.

Vocabulary:
-Kalimba
-Xylophone
-Pitch.

This lesson could be taught grades 2-4 (however, it could also be adjusted for upper and lower grades) with a class size between 20 to 25 students. With a larger class size, it might be more effective to have two of each of the stations set up so that all students get the opportunity to explore with each sound station. This lesson can be done in a regular classroom space. In order for students to have the opportunity to complete all stations, 50-60 minutes or two 30 minutes blocks of time are needed. Special equipment needed includes: straws (that need to be cut at one end to form a mouthpiece), xylophone, five glass bottles with various amounts of water in them, palm pipes (different lengths of PVC pipe cut up), and a kalimba or string harp (a thumb piano made from a small wooden box, wooden dowel, wing nuts, and popsicle sticks, or you could also use a string harp made from a block of wood with different sized fishing line attached with nails on top). This lesson is part of our 3rd grade Foss Science curriculum, however I added some sound activities I learned from Elementary Physics class. This year I will be teaching in a 2nd/3rd grade multiage class, so I will be adapting it for 50 students.

Materials Needed:

-Student science notebooks and pencil
-2 waterphones (five identical glass bottles filled with water and one mallet)
-2 xylophones with mallet
-25 straws (already cut on one end to form a pointy mouthpiece)
-2 sets of palm pipes (PVC pipes cut to a variety of sizes)
-2 kalimbas (a thumb piano made from a small wooden box, wooden dowel, wing nuts, and popsicle sticks) or string harps made from a piece of wood and various lengths -of fishing line strings attached with small nails or pins
-Clock or timer
-Chart paper and markers
-Palm pipes music sheets for each student

Procedure:

1. Introduce the investigations by telling students the challenge for today- to find a conclusion about sound after visiting all five sound stations. Today's question we are investigating is, "How does the length of an object affect the pitch of the sound?" Talk with students about the word "pitch" and what it means. Show (but don't demonstrate) each of the sound stations (including: straw flutes, xylophone, water phone, palm pipes, and kalimba) and show students how to use each instrument. Next, students will get out their science notebooks and turn to the Sound section. Then, students can write a hypothesis for today's lesson. Ask, "What do you think you will discover during today's lesson?" Revisit today's question. Students can talk with their table to help come up with an idea. Have groups share their hypotheses.
2. Before beginning the investigation stations, go over expectations for students during this activity. Explain that students will get five minutes to explore each station. During those five minutes all students in your group must have the opportunity to try the instrument. Also, everyone must write their observations in their science notebook (2 sentences minimum for each station). Assign one person in the group to be the starter. The starter's job is to make sure everyone in their group gets a turn and also watch the clock. Also, go over how to treat materials with care and noise level expectations. Tell students what your signal will be to clean up their station, and move to the next.
3. Assign students a sound station to begin at (make sure to have them bring their science notebook to write down their observations from each station). Remind students of the signal when it is time to clean up and rotate. Then, students can begin their investigation. While students are working, visit groups and remind them to record their observations in their notebooks. Have students continue rotating until they have completed all stations. Have students help clean up materials and return to their seats.
4. With their table groups have students share their observations from each station. Then, each group needs to come up with a conclusion about length and pitch from today's stations. Have one student report their group conclusion. Make sure all students have something similar to this: a long object has a low pitch and vibrates slowly and a short object has a high pitch and vibrates quickly.
5. To conclude today's lesson, ask students to write one thing (in their notebook) they are still wondering about sound. Have a few students share their wonderings. Add those questions to the "Questions about Sound" chart. Another follow-up question you could ask is, "What other objects or instruments can you think of that make different pitches by changing the length of the sound source?"
6. If time allows, or possibly the following day, I would like to have each student in class take one of the palm pipes and we will play a few songs together as a class. I have a handout that tells the length of each pipe and the note assigned to it along with a few simple songs. Each palm pipe has a note assigned to it based on its length. I think this would be a fun wrap-up activity to conclude what students learned about length of the object and pitch.

This lesson has been modified from Foss: Physics of Sound, Investigation 2: Good Vibrations, Part 2: Length and Pitch. Published by Delta Education, Nashua, NH, 2000

I have not taught this lesson before, but a few things that might need reinforcement include going over rules for the stations/expectations for students. It also might be helpful to model writing an observation for student notebooks so they know what your expectations are. Another thing you probably will want to talk with students about is the noise level. Since this is a lesson in which students will be making sounds with a variety of instruments, it would be beneficial to go over how loud/quiet the sounds you make should be. Since I have not taught 3rd grade before, this lesson is very different from what I have taught in 2nd grade. One thing though that I feel I have added to this lesson that it was missing from Foss was the hypothesis part. I want students to predict what they think is going to happen before they complete the stations instead of just talking about what they observed when we're done.

I will assess students on this lesson through my observations throughout the activity along with collecting their science journals and checking their observation sentences, hypothesis, and conclusion. I will also be assessing students' participation in class discussions and the sound stations.

Grade 3:

II.C.1 Energy transformation

The student will investigate how sounds are made when objects vibrate.