Grade-9 Sound

• physics, science
• Secondary Education

SCIENCE

GRADE-9

NOV 1, 2020

Ms. Famin

OBJECTIVES 

Describe how sound waves are produced

Relate the speed an temperature of sound waves with the materials used.

Interpret 

What do all sounds have in common?

How is sound produced?

video 

Sound waves

Sound is a longitudinal wave, meaning that the motion of particles is along the direction of propagation

Transverse waves—water waves, light—have things moving perpendicular to the direction of propagation

Analyze 

How do vibrating object produce sound waves?

Where do you think the sound moves faster?

Predict - Would a barking dog produce sound waves that travel faster during the day r night?

TRIVIA 

The speed of the sound wave in a material increases as the temperature of the material increases

a sound wave in air travels faster on a warm, summer day than on a cod winter day

SCIENCE 

GRADE-9

NOV 2, 2020

Ms.Famin 

in which case is the speed of sound more

objectives 

Relate the speed of sound waves and temp on different materials.

describe the parts and function of human ear 

recall 

RECALL 

In which material do sound waves travel fastest?

1. aluminum
2. ethanol
3. carbon dioxide
4. water

What is the area of low density in a sound wave called?

1. wavelength
2. compression
3. rarefaction
4. amplitude

What is a longitudinal wave?

1. a wave in which the electromagnetic field changes parallel to the direction of the wave
2. a wave in which the electromagnetic field changes perpendicular to the direction of the wave
3. wave in which particles in matter move perpendicular to the direction of the wave
4. wave in which particles in matter move in the same direction as the wave

FIRST 

steel at 0 C

water at OC

water at 30 C

air at 0C

air at 30 C

CHALLENGE- If a sound wave travels at 1, 620 m in 3 s, what is its speed?
[DO NOT FORGET THE UNIT]

CHALLENGE- At 331 m/s, how far would sound
travel in 0.5 seconds? [do not forget units ]

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Functions of parts of ear

• the outer ear- collects sound waves. the ear canal channels sound waves into the middle ear.
• The middle ear- It amplifies sound waves. It has eardrum and three tiny bones-hammer, anvil and stirrup. When sound hits ear drum it vibrates and the three bones amplify
• The inner ear- it converts vibrations to nerve signals thta travels to brain. It has small fluid like chamber called cochlea. 

Which part of the ear acts as the amplifier?

1. cochlea
2. nerves
3. inner ear
4. middle ear

Which part of the ear converts vibrations to nerve signals ?

1. inner ear
2. outer ear
3. middle ear
4. ear canal