Sound/Pitch

Joan Cwiklik O.A. Thorp Scholastic Academy
6024 West Warwick Avenue
Chicago, Il. 60634
312-534-3640

Objective:

To discover how pitch can be changed in instruments that are plucked (strings),
blown (woodwinds and brasses) or hit (percussion).

Bottle Music Materials Needed:

Each group needs 5 bottles of the same size (empty pop bottles work well),
water. Optional: Funnel (for filling bottles).

Strategy:

1. Fill one bottle with water almost to the top. Fill the second bottle about
three-fourths full, the third half full and leave the last bottle empty.
2. Blow across the top of each bottle. Listen to the highness/lowness of each
bottle's note.
3. Record your data.

Conclusions:

When you blow across the top of each bottle, it makes the air inside the bottle
vibrate. Small air spaces vibrate more rapidly than large air spaces. When
there is little air in the bottle, you produce a high note. When there is more
air, the note is lower.

Underwater Recorder Materials Needed:

Each child needs his recorder, duct tape and a tall container of water.

Strategy:

1. Cover all the finger holes in the recorder with duct tape. Blow gently into
the recorder and you should hear a single, low-pitched note.
2. Take a deep breath and blow into the recorder while you push it into the
water. What happens to the pitch of the note?
3. Take another breath and blow into the recorder again while you pull it up
out of the water. How does the sound change?

Conclusions:

When you blow into the recorder, the air inside it vibrates and you hear a
note. The pitch of the note depends on the length of the column of air inside
the recorder. When you push the recorder under the water, the water fills up
the tube so the column is shorter. You hear a high-pitched note. As you pull
the recorder out of the water, the column of air becomes longer and the note
sounds lower.

Pipes of Pan Materials Needed:

Five pieces of bamboo or hollow plastic (PVC) piping, cut into the following
sizes: 2, 31/2, 5, 61/2 and 8 inches; non-drying modeling clay and sticky tape.

Strategy:

1. The pieces of pipe are cut to different lengths ranging from 2 to 8 inches.
2. Push a piece of modeling clay into one end of each tube.
3. Arrange the pipes in order of length, with the shortest pipe at one end and
the longest pipe at the other end. Tape the pipes together so the open ends
are exactly level with each other.
4. To play your Pipes of Pan, place the edge of the open end of the pipe
against your lower lip and blow gently across the top of the pipes.
5. What do you notice about the pitch of the notes from the different pipes?

Conclusions:

You should discover that the longer pipes give lower notes and shorter pipes
make higher-pitched notes.

Glass Xylophone Materials Needed:

For each group: 5 glass containers that are the same size (such as empty pop
bottles), water, wooden spoon or mallet, funnel for filling bottles.

Strategy:

1. Fill one bottle with water almost to the top. Fill the second bottle about
three-fourths full, the third half full, the fourth a quarter full and
leave the last bottle empty.
2. Tap the side of each glass gently with a wooden spoon. Each glass will ring
with a note of a different pitch. Which glass makes the highest sound and
which glass makes the lowest sound?

Conclusions:

When you tap each glass, it makes the glass vibrate. The pitch of the note
depends on the amount of water in the glass. With more water, the pitch of the
note is lower.

Other activities which were demonstrated include Elastic Band Guitar for
exploring stringed instruments and Tapping and Hitting for discovering pitch in
percussion instruments.
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