Physics of SoundInvestigation 2, Lesson 2Length and Pitch

MATERIALS• Student Sheet no. 6 called the Waterphone• Student Sheet no. 7 called the Xylophone• Student Sheet no. 8 called the Kalimba• Student Sheet no. 9 called the String Beam• Large plastic bags• Meter tape• Scissors• Door fiddle (cord with bead with wood block)• 5 identical glass soda bottles with caps 12 oz• Mallet• Water• 5 xylophone tubes• Foam piece • Kalimba base• 5 flat steel springs• Craft sticks• Half meter stick with notch at end• Half of a craft stick• Fishing line about 125 cm• Binder clip• Paper cup

Kalimba (for teacher)

•Loosen the wing nuts•Slide the 5 steel springs under the dowel•Adjust the springs so each is different

length•Tighten the wing nuts•Play with thumbs or craft sticks

Waterphone (for teacher)•Fill 5 12 oz glass bottles with varying

amounts of water•Bottle with least amount of water should

contain at least 3 cm of water•Tap under the water line of the bottles to

determine whether they produce pitches that are recognizably different

•When tuned, screw on caps.•Put a mallet with them.

Xylophone (for teacher)

•Picture•Place 5 different lengths of aluminum

tube in foam piece•Need a mallet

String Beam (for teacher)• Tie a knot in the end of a 125 cm piece of fishing line• Slip the line into the slit cut into the 50 cm end of the half

meter stick• Pull the knot up against the stick on the back• Poke 2 small holes in a paper cup near the base• Run the line through the cup• Run the line the length of the stick, around the end, and

up the back of the stick.• Thread the line back through the slit.• Pull the line tight.• Put the binder clip over the end o the stick to hold the line.• Use scissors to cut a craft stick in half.• Insert the craft stick as a bridge between the fishing line

and the 0ther end of the half meter stick. (This will increase the tension.)

4 New Sound Instruments• Waterphone

▫ Strike the bottle with mallet below the water level to produce the best sound.

• Xylophone▫ This is a musical instrument made from a set of bars or tubes

that make sounds with different pitches.• Kalimba

▫ An African thumb piano.▫ Demonstrate how to insert, adjust, and play the steel springs.

• String Beam▫ Caution: Do not remove the binder clip.▫ Show how to hold the cup with one hand and pluck the string

with the other. ▫ May need to get close because it is not very loud.

Rules for exploration time• Around 5 minutes to explore each instrument

• Strike the xylophone tubes or bottles gently

• Treat the instruments with care

• Will rotate instruments

• Make sure everyone in your group gets a turn.

• Record observations make in notebook.

Discussion • Discuss observations.

• Discuss how long the object made the sound or the length of the sound source.

• Discuss the pitch of its sound.

• Discuss the frequency of the vibrations. (A low frequency vibration makes a low pitched sound. A high frequency vibration makes a high pitched sound.)

Review • Kalimba – African thumb instrument• Xylophone – musical instrument made from a set

of bars or tubes of different lengths• What happens to the pitch and the vibrations

when the length of the sound source change? (A long object has a low pitch and vibrates slowly. A short object has a high pitch and vibrates quickly.)

• What are some musical instruments that make different pitches by changing the length of the sound source? (trombone, flute, recorder, harp)

• Science Story – Making Waves and Sound Off

The End!!!