Musical Instruments



MUSICAL INSTRUMENTS

Pre-Lab Question

What is a note? What is pitch?

EXPLORATION

Exploration Materials

1 cork

2 drinking straws (1 large, 2 small)

1 PVC tube

Scissors

1 wood rod

1 plastic mouth-piece

1. Build a slide flute with the large straw, the plastic mouth-piece, and the wooden rod, as shown below.

Take the mouth-piece and the straw, and cut a small triangle in the straw a mouth-piece length from the end.

[pic]

Figure 1: Slide Flute parts

[pic]

Figure 2: Mouthpiece inserted with triangle cut at base

Insert the mouthpiece so the angle rises as it approaches the triangle cut. To optimize the flute, pinch and distort the straw at the triangle cut. You want the diameter of the straw at the triangle cut to be less than at the mouth piece.

Insert the wooden rod into the straw’s base. This can slide up and down the flute while it is being played.

2. What do you observe when you slide the wooden rod up and down while blowing on the flute? Describe how and why the sound is different.

Have one team member play the flute. Have them play a piece of music, see if you can recognize it.

3. Build an oboe

Take the small straws and cut them in half, distribute one piece to each group member. These pieces will be your reeds. Cut ½ an inch off the end of the straw in a triangle pattern.

[pic]

Figure 3: Straw cut into a reed

Flatten the two straw pieces together, and cut into a triangular shape leaving the tip at your mouth (don’t make it too sharp).

Insert the unfinished end of the straw all the way into the rubber cork. Plug the cork into the PVC pipe.

Prepare to the play the “oboe.” It will take some practice to get a sound. It is helpful to pinch the reed together gently with your lips or teeth while blowing.

Play the oboe. Try to get different sounds. What do you change to achieve different sounds?

Each person has a reed; each person should try to play the oboe. Do you notice a difference with different reeds and players? Explain what you observe.

Compare what you observe with the oboe with what you observed in the slide flute. Does one instrument have a better or richer sound quality?

Challenge Work:

Are the different sounds you hear on the slide flute due to changes in loudness (volume)? Explain.

Why do different instruments playing the same note sound unique? Explain.

[pic]Everyday Applications

• All Musical Instruments

• Music production software

• Dog whistles

APPLICATION

Materials

1 pre-assembled Petri microphone

1 amplifier

1 1/8th inch-double bare ends wire

1 alligator lead card

1 guitar apparatus

1.

[pic]

Figure 4: Electric Guitar

Pluck your “guitar.” What causes the sound you hear?

Press down on the guitar string firmly with a pencil and pluck again. This is called “forcing a node.” How did the sound change and why? Explain. Is this similar to the flute and oboe?

2. Assemble your Petri device so it is a microphone attached to the amplifier as shown below.

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Figure 5: Petri microphone

Place the Petri microphone under the guitar string, with the magnet-side nearest to the string. Get some cellophane tape and tape the microphone to the base (this will prevent the magnet from being attracted to the string).

Turn on the amplifier and pluck the guitar again. How does adding the microphone change the sound of the guitar?

Challenge Work:

1. What is the general relationship between the size of an instrument and the pitch of the sound that it produces?

2. How do you make instruments start vibrating? List at least four ways.

Summary:

Final Clean-up

Please disconnect all alligator leads and reattach them to the clip card. You are finished with the microphone and loudspeaker, but some parts are re-used so please return the device to the cart. Return all equipment to the carts.

Bibliography and recommendations for further reading:

Wikipedia contributors, "Pitch (music)," Wikipedia, The Free Encyclopedia, (accessed July 7, 2006).

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