Julie Franzak

ELED 305-42

6/5/2007

Science Area: Life Science- Sound

5.14- Volume (Intensity) & Pitch

Pitch is dependent on how fast an object vibrates

12.C.2a. Describe and compare types of energy including light, heat, sound, electrical and mechanical.

13.A.2b. Explain why similar investigations may not produce similar results.

1. Hold the comb in the air while plucking the teeth with your fingernail.

2. “How can I amplify the sound?”.

3. Hole the comb against a table and pluck it again.

4. Distribute different combs to each student and allow them to hold the comb against difference surfaces and different materials (in the class).

*Listen which of the surfaces gives the best amplification.

5. Notice the difference in pitch.

6. Point out to the class that the different lengths of the teeth give different pitches.

*Teacher can pluck simple tunes.

When the comb was held against the table, the teeth, the comb and the table were all vibrating; doing this increases the surface of the vibrating object mainly causing an increase in loudness or amplification. The distance from the sound source, the amplitude of the wave (how hard the teeth were plucked), and the surface area of the vibrating object are all factors that affect the loudness of a sound. The best materials for intensifying quality in sound amplification are wood sheets and wooden boxes. This is the main reason why sound boards in pianos, guitars, violin bodies and speaker boxes are all made out of wood.

Liem, Tik L. Invitations to Science Inquiry. Chino Hills, CA: Science Inquiry Enterprises, 1987. 293.

Julie Franzak

ELED 305-42

6/5/2007

Science Area: Life Science-Sound

5.14- Volume (Intensity) & Pitch

Pitch is dependent on how fast an object vibrates

#2

11.B.2c. Build a protoype of the design using available tools and materials.

12.C.2a. Describe and compare types of energy using light, heat, sound, electrical and mechanical.

13.B.2b. Describe the effects on society and technological innovations (e.g., antibiotics, steam engine, digital camera).

1. Cut small holes on one side of one of the straws (~ 1-1.5cm apart from each other).

2. Flatten one end of both straws and cut triangle pieces out.

3. Place the just cut end of the straw with the hole in your mouth.

-hold your lips just where the ends were cut and blow until you produce an oboe sound. (Shift the straw in or out of the mouth slightly to help obtain the desired sound.)

4. Place 3 fingers from your left hand on the farthest 3 holes of the straw.

5. Place 3 fingers from your right hand on the nearest 3 holes of the straw.

6. Open or close holes to obtain different pitches.

7. Blow the straw with no holes. Have a partner cut small pieces off the straw while you are blowing.

This activity shows that the length of vibrating air determines the pitch of a note. When the end of each of the straws were cut it created a reed-like protrusions; when the air is blown through the reed-like protrusion, it vibrates and creates the oboe sound. The air column in the straw is also vibrating and helps produce the pitch. The holes in the straw allow you to make the vibrating air column shorter or longer; this effect is also created by opening and closing a hole or several holes simultaneously. This principle can also be applied to the flute, clarinet, oboe, saxophone, as well as other varieties in soprano, alto, tenor and bass instruments.

Liem, Tik L. Invitations to Science Inquiry. Chino Hills, CA: Science Inquiry Enterprises, 1987. 295.

Julie Franzak

ELED 305-42

6/5/2007

Science Area: Life Science- Sound

5.14- Volume (Intensity) & Pitch

Pitch is dependent on how fast an object vibrates

12.C.2a. Describe and compare types of energy including light, heat, sound, electrical and mechanical.

12.C.2b. Describe and explain the properties of solids, liquids and gases.

1. Fill the 3 identical bottles with different amounts of water.

-“Which bottle will give the highest tone when I hit it on the side with a ruler?

2. Lift the bottle with 2 fingers at the neck and hit the side of each bottle with the ruler.

-Listen to the pitch of the tone.

3. “Will bottle C always give the highest pitch?”

4. Blow over the bottle mouth (place lower lip on the bottle rim and blow a narrow stream of air in a horizontal fashion over the mouth).

-Listen to the tone/pitch.

When the ruler was used to hit the bottles, the bottle and the water were the two factors that vibrated to produce the sound pitch. The more water in the bottle the lower the pitch observed. When blowing over the bottle with your mouth, the air above the water produced the tone; the larger the column of air in the bottle, the lower the pitch. Therefore, the more mass of the material that vibrates, the lower the pitch it produces. For the guitar and the piano, the lower and deeper tones are produces by the larger and longer strings. If the strings are shortened (by placing the finger on a fret), a higher pitch is obtained. This activity can also be done by using different liquids and filling the bottles with the same amounts. When the ruler hit’s the bottles containing different liquids, the pitch would probably be different due to the differences in masses. When air is blown over the mouth, the tone would stay the same because the air column stayed the same.

Liem, Tik L. Invitations to Science Inquiry: Supplemental 1^st and 2^nd Edition. Chino Hills, CA: Science Inquiry Enterprises, 1991. 95.