1.Sound must have a medium through which to travel. Through which medium – solid, liquid, or gas – does sound travel faster?

2.How are different musical notes made with a wind instrument, such as a clarinet?

3.On a string instrument, such as a guitar, how does one string make different musical notes?

Bellringer (Answer ONLY)

Chapter 15

Sound & Light

I. Section one – Sound

A. Sound waves – longitudinal (compression) waves that vibrate in the same direction they travel.

1. Sound waves:

i. Are caused by vibrations.

ii. Travel through a medium.

iii. Carry energy.

B. The speed of sound depends on the _______.medium

1. Speed of sound in air: 346 m/s

2. The speed of sound depends on how often the molecules that make up the medium collide.

And…

3. The temperature of the medium.

C. Loudness and Intensity

1. Loudness is proportional to the energy contained w/in the sound wave.

2. Intensity = amplitude + distance from sound source (volume).

3. Loudness – intensity of the sound.

D. Loudness is measured in decibels, dB.

1. A 10 dB increase equals a sound that is 2x louder.

2. Intensive exposure to sounds over 120 dB can cause permanent deafness.

E. Pitch and Frequency.

1. Pitch = “highness” or “lowness” of a sound.

2. Higher frequency = higher pitch.

i. Higher frequency = faster vibrations being produced.

F. Human hearing1. Humans can hear sounds in the range

of 20 Hz to 20,000 Hz.

Questions:

1.What are the three parts that make up a human ear?

2.What part(s) make up the middle ear?

3.Sound can travel through ___, ___ & ___.

How the human ear works

Questions:

1. What are the three parts that make up a human ear?

A. Outer EarB. Middle EarC. Inner Ear

2. What part(s) make up the middle ear?The eardrum & three tiny bones

3. Sound can travel through gases, solids & liquids.

G. Musical Instruments

1. Musical instruments can be grouped into three categories based on how they produce sound:

i. Vibration of strings.

ii. Vibration of air columns.

iii. Vibration of membranes.

2. Resonance – Two objects naturallyvibrate at the same frequency.

i. Results in amplification of the sound.

H. Ultrasound & Sonar

1. Sound can be used to make images.If you know:

i. The speed of sound in a specific medium.

ii. The time it takes for the sound to travel to an object and bounce off of it

iii. The distance to the object can be calculated.

2. Ultrasounds and sonarFrequencies above 20 kHz.

Class work assignment:

Section 1 review, Pg. 498, Questions 1 – 10 Write questions AND answersNumber 3 in your notebook