Properties of Sound Lab

Properties of Sound Lab

Kyle C.

7A

Purpose: To determine how changing amplitude and frequency can change how a sound is perceived.

Procedure:

Experiment no.1: Amplitude

1. Have 2 partners each hold one end of the thicker rubber band and pull until the rubber band is taut (not loose).

2. Pull the rubber band about 1 cm away from the middle. Let it go. How far does the band move? Describe the sound you hear in the table below.

3. Repeat step 2 four more times. Each time, pull the band back further. Describe how the sound changes each time in the chart below.

Experiment no. 2: Frequency

1. Have 2 partners each hold one end of the thicker rubber band and pull until the rubber band is taut (not loose).

2. Pull the rubber band about 2 cm away from the middle. Let it go. Observe the sound.

3. Repeat step 1-2 with the thin rubber band and describe the difference in the chart below.

4. Now, take the thicker rubber band again. Repeat 1-2.

5. Now pull the thicker rubber band a little bit tighter and repeat steps 1-2. Observe how the sound changes.

6. Pull the rubber band even tighter and repeat steps 1-2. Observe how the sound changes. Record your observations in the chart.

7. Last experiment: have two partners hold the thick rubber band just like in step 1. Repeat step 2 and observe the sound.

8. Now, have one of your partners move his or her hand so that the rubber band is a little bit shorter. Repeat step 2 and observe the change in sound.

9. Repeat step 8 2 more times, making the rubber band a little shorter each time. Record your observations of the change in sound.

Results:

Experiment no.1

Distance away from middle	Description of sound
1cm	Low pitch
2cm	Bit higher than before but still low
3cm	Average
4cm	High pitch
5cm	Very high

Experiment no.2

Thickness of Rubber Band	Description of Sound
Thick	Sound of base guitar
Thin	Sounds like a guitar which needs to be tuned (tuning problem)

Tightness of Rubber Band	Description of Sound
Loose	Can’t hear anything
Tight	Sound like deep
Tightest	Loud

Length of Rubber Band	Description of Sound
Longest	Average sound
Long	Loud and High
Shortest	Bit higher than before

Conclusion:

1. How did the sound change when you changed the amplitude (how far the rubber band was away from the middle point)?

My record suggested that when adjusting the amplitude of the rubber band, the pitch when increasing will become exquisite like it will form beautiful sounds.

2. What happened when you changed the thickness, length, and tightness of the rubber band?

When I altered the thickness, length, and tightness of the rubber band, the sound and volume of them increased (for some reason).

3. Sally is playing the guitar and notices that one of her strings is flat (pitch is too low.) What can she do to fix this?

Sally should tighten the string the guitar to make it better. (Increasing the pitch)