Reflection and Absorption of Sound Waves

Reflection and Absorption of Sound Waves

How are sound waves reflected and absorbed?

Review

What do we remember about waves...

Multiple Choice

Sound is a mechanical wave because

• Sound waves moves perpendicular to the disturbance

• Sound waves moves in the same directions as the disturbance

• Sound waves move through the vacuum of space

• Sound waves must have a medium through which to travel

Multiple Choice

Materials through which sound travels is called slowest is

• liquid

• gas

• solid

• plasma

Multiple Choice

The fact that seismic waves (earth quake waves) travel for many kilometers but do not move the ground with them where they go is an example that

• waves transfer matter not energy

• waves transfer both matter and energy

• waves transfer energy not matter

• waves transfer neither matter nor energy

Multiple Choice

The disturbances that travel in a sound wave are called

• vibrations

• magnetic field

• compressive force

• low pressure

Multiple Choice

To raise the pitch of a sound wave what must happen to the wave?

• Increase the wavelength of the wave

• Decrease the amplitude of the wave

• Decrease the energy of the wave

• Increase the frequency of the wave

Multiple Choice

What happens to the pitch of the sound when the amplitude increases?

• the pitch gets higher

• the pitch gets lower

• the pitch doesn't change

• the pitch gets louder

Recall that sound waves are mechanical waves and need a medium to travel.

When the medium the sound is traveling through encounters a barrier four things can happen.

Wave Interactions include

• Reflection

• Absorption

• Refraction

• Diffraction

Today our focus is

• reflection

• absorption

Sound behavior is influenced by the medium a sound wave travels through and the obstacles the wave comes in contact with. All waves can be

• reflected

• absorbed

• refracted

• diffracted

Reflection of a sound wave

Sound waves can be reflected when a sound wave hits a barrier and bounces back. The types of barriers that cause sound reflection are smooth flat surfaces. Examples of this are echoes, echoloaction, sonar and ultra sound.

Multiple Choice

What is echolocation?

• the location of objects by reflected sound, in particular that used by animals such as dolphins and bats.

• the location of objects by reflected light, in particular that used by animals such as dolphins and bats.

• the location of objects by refracted sound, in particular that used by animals such as dolphins and bats.

• the location of objects by diffracted sound, in particular that used by animals such as dolphins and bats.

Multiple Choice

What do we call sounds humans can't hear?

• infrasound

• sound

• ultrasound

• pitch

Multiple Choice

Which of the following is the term for the fact that when sound waves move away from a source they are farther apart and lower in pitch?

• Echolocation

• Sonar

• Doppler Effect

• Hertz

Absorption of Soundwaves

Sound waves can be absorbed when a sound wave causes particles to vibrate absorbing the sound and changing the sound into another form of energy.

Multiple Choice

What type of materials are used to absorb sound?

• Smooth Flat Surfaces

• Soft Surfaces

Multiple Choice

True or False: Too much noise or too little noise can make people feel uncomfortable.

• True

• False