Download Musical Pipes - Particles Matter

Musical Pipes
Teacher Notes
Concepts: (1) Sound is a type of energy produced by a vibration. [6.2.3.1.1] (2)
Changing the length (width, tension, etc.) of the vibrating material changes the
pitch of the sound produced. [3.2.3.1.1]
Questions to get students thinking before the activity or to use after:
•What is inside a piano?
•Haw are a violin and cello or piccolo and flute or trumpet and trombone
alike? How are they different? How are the sounds they produce different?
•How do you tune an acoustic guitar?
•How does the pitch of a drum change if you tighten the drum head?
•What do you hear when you run the mallet down the bars of a xylophone?
Materials per group:
2 or 3 lengths of PVC pipes - make sure each student has one pipe - and the
pipes within each group are of different lengths (label each pipe with the letter
of the note) PVC (½ inch inside diameter) is available at home improvement
stores and is easily cut with a hand saw - great place to get your dads involved!
two octaves worth of pipes for the whole class to play a song
The palm pipes are cut out of ½ PVC pipe to the following lengths. These pipes
are set to play anything in the key of F.
Note
Length (cm)
Frequency (Hertz)
Note
Length (cm)
Frequency (Hertz)
F
11.8
698
F
23.6
349
G
10.5
748
G
21.0
392
A
9.4
880
A
18.75
440
B♭
9.2
932
B♭
17.5
466
C
7.9
1046 (high C)
C
15.8
523 (middle C)
D
7.0
1174
D
14.0
587
E
6.25
1318
E
12.5
659
F
5.9
1397
Procedure: Introduce this activity with a guitar (or other string instrument) and
someone that can play it. Have the musician describe what they are doing
while tuning the guitar. This gives you the opportunity to talk about pitch. We
describe the frequency of sound with the term pitch. Materials that make more
vibrations per second have a higher pitch (like the sounds made by the keys on
the right end of a piano) and materials that make fewer vibrations per second
have a lower pitch (like what we hear from the keys on the left end of a piano).
Depending on your musical ability and the age of your students, you can talk
about the numerical frequency of the notes and graph length (independent
variable, horizontal axis) vs frequency (dependent variable, vertical axis). The
graph is not linear. There are many musical/mathematical relationships that can
be discovered and discussed. Pipes that play notes one octave apart have a
length ratio of 1:2. Notes that sound good together have length ratios that are
small whole numbers. When lined up from shortest pipe to longest pipe students
will observe the pitch decreases.
Scientific method (controlling variables) extension or revisiting the guitar: What
happens to the pitch of the sound produced when a string (wire) is stretched?
Have a student pluck a rubber band as you stretch it. Yes, the pitch increases,
but is this a fair test? Not really. Too many variables are changing at the same
time. The length is increasing along with the tension while the width is
decreasing, How would you develop a fair test of the relationship between
tension and pitch?
Observations/Results: Sounds can be made in many ways. Pipes can be tapped on a
hard surface, blowing across one end of the pipe with the bottom open and
closed and hitting one end on the palm of a hand. A slightly different pitched
sound will be made if the pipe is hit and held on the palm. Students may or may
not hear a difference in the sound created by different methods. They may
describe loudness, quality and possibly pitch. When comparing the sounds
made by different pipes a relationship emerges: The longer the pipe the lower
the pitch (frequency) of the sound generated.
Summing Up:
1.What is true about the pitch of the short pipes? What is true about the pitch of
the longer pipes?
Short pipes have higher pitches and longer pipes have lower pitches.
2.Circle the pipe that you expect to produce the sound with the lowest pitch.
The longest pipe will have the lowest pitch.
3.Here is a picture of a harp. A harp is played by plucking the strings. Which end
of the harp do you expect to play the notes with the highest pitch? Why did you
pick your answer?
The highest pitch notes will come from the shortest strings. This is the same
relationship discovered during the activity.
Make sure to play Twinkle, Twinkle, Little Star as a class. Everyone with the note plays as
indicated (no matter what octave).
Musical Pipes
Materials: 2 or 3 different lengths of PVC pipe
Procedure:
1. Brainstorm all the ways you could make a sound with a piece
of PVC pipe. List the different ways below. Work with one pipe
and try out your methods. Name the method and describe
the sound you produced.
2. Does one pipe make the same sound no matter how it’s
made?
3. Quickly hit one end of the pipe on the palm of your hand.
Listen to the pitch of the sound. Use three pipes of different
lengths and compare the pitch of the sound. Describe your
results in the data table below.
Length of pipe
Pitch
short
medium
long
4. Find the note written on your pipe. Form a new group with all
members having the same note. Are all the pipes that play
the same note cut to the same length?
5. Measure the pipes. Listen to the pitch each pipe produces
when hit on the palm of your hand. Make a data table to
hold the information.
6. As a whole class, line up in order from the shortest pipe to the
longest pipe. Play the pipes in order. What do you observe as
the pipes are played?
Summing Up:
1. What is true about the pitch of the short pipes? What is true
about the pitch of the longer pipes?
2. Circle the pipe that you expect to
produce the sound with the lowest
pitch.
3. Here is a picture of a harp. A harp is
played by plucking the strings. Which
end of the harp do you expect to
play the notes with the highest
pitch? Why did you pick your
answer?
Twinkle, Twinkle, Little Star
Melody
FF
CC
DD
C
little
star, how
Twinkle, twinkle
Harmony C C
Melody C
Up
A A B♭B♭ A
C Bf
above
Harmony A
AG
Melody C
C
Like
Harmony A
Melody
B♭
Bf
A
A
G
F
F
G
A
G
a diamond
in
the
sky,
A
F
F
C
DD
C
B♭
little
star, how
Twinkle, twinkle
Harmony C C
G
F
wonder what you are.
F F
E
E
F
AA
G
G
F
C
A
CC
G
G
high,
B♭B♭
FF
I
AA
G
the world so
GG
B♭
A A B♭B♭ A
G
B♭
I
G
wonder what you are.
F F
E
E
F