Question

pre - reading

1. what is the loudest sound that you have heard? describe...
2. have you ever heard something so loud that you could also feel the sound in your chest? how do you think this happens?
3. despite amazing advances in cell phone technology, (anyone remember flip phones?) modern cell phone speakers are still not very powerful, what do you think limits them?

during - reading-

1. what produces the sensation of sound?
2. what is ultrasound?
3. what is an elastic medium? give some examples.
4. anything that imparts a ________ to an elastic medium is a source of ________
5. what are the two subjective qualities of sound?
6. what are the two objective, measureable, qualities of sound?
7. what do air molecules do when a sound is made?
8. what is compression?
9. what is rarefaction?
10. what makes the intensity of the source decrease rapidly?
11. assuming they were the same loudness, a smoke alarm has a __________ pitch than thunder.
12. in general, what causes a rise in pitch?

Explanation:

These questions pertain to the science of sound. Sound is a mechanical wave that requires a medium to travel. The sensation of sound is produced by vibrations in the ear. Ultrasound is sound with a frequency higher than the upper - limit of human hearing. An elastic medium is one that can return to its original shape after being deformed, like air, water, and solids. Sound sources impart vibrations to elastic media. The subjective qualities of sound are loudness and pitch, while the objective qualities are frequency and amplitude. When sound is made, air molecules vibrate, creating compressions (areas of high - density) and rarefactions (areas of low - density). The intensity of a sound source decreases rapidly due to spreading of the sound wave. A smoke alarm has a higher pitch than thunder at the same loudness, and an increase in the frequency of a sound wave causes a rise in pitch.

Answer:

1. Vibrations in the ear produce the sensation of sound.
2. Ultrasound is sound with a frequency higher than the upper - limit of human hearing (above 20,000 Hz).
3. An elastic medium is a substance that can return to its original shape after being deformed. Examples include air, water, and solids like steel.
4. Anything that imparts a vibration to an elastic medium is a source of sound.
5. The two subjective qualities of sound are loudness and pitch.
6. The two objective, measurable, qualities of sound are frequency and amplitude.
7. When a sound is made, air molecules vibrate back and forth, creating areas of compression and rarefaction.
8. Compression is an area in a sound wave where the molecules are closer together (higher density).
9. Rarefaction is an area in a sound wave where the molecules are farther apart (lower density).
10. The spreading of the sound wave in three - dimensional space makes the intensity of the source decrease rapidly.
11. Assuming they were the same loudness, a smoke alarm has a higher pitch than thunder.
12. In general, an increase in the frequency of a sound wave causes a rise in pitch.