SoundSOL 5.2

What is Sound?

• Sound is a form of energy that is produced and transmitted by vibrating matter as it moves backwards and forwards.

• They must have a medium to travel through. Sound cannot be produced in a vacuum.

• Sound waves are called compression waves, or longitudinal waves.

What does a compression wave look like?

Parts of a Compression Wave• 1. Compression- Where the particles are pushed

together.• 2. Rarefaction- Where the particles are spread apart. • 3. Wavelength- The distance between two

compressions or two rarefactions.

Sound

• Sound is measured in decibels

http://www.youtube.com/watch?v=ACeUO4ufx2I

Label the Compression Wave

Compression Wave

http://www.youtube.com/watch?v=r4xYDs5rLNI

How Do People Use Sound?

Sound

• Sound travels in waves called sound waves.

• Sound is measured in decibels.

How Do Humans Use Sound?

• Communication

• Safety

• Music

Sound

• The frequency is the number of waves moving past a point in one second.

• The faster the song, the higher the frequency.

• The pitch is a measure of how high or low a sound is.

http://www.youtube.com/watch?v=b4OCVPh9eD8

What is Amplitude?• The height of a sound wave is called the

amplitude. (Think of an “amp” at a rock concert)

• The higher the wave, the more energy it carries.

Musical Instruments

• Musical instruments vibrate to make different sounds.

1. Woodwinds: Produce sound by blowing air into one end and pressing keys or levers.

Musical Instruments

2. Percussion: Produce sound by striking, scraping, or rattling with hands.

Musical Instruments

• 3. String: Produce sound by plucking, strumming, or bowing.

Musical Instruments

4. Brass: Produce sound by blowing air through a mouth piece and pressing keys.

http://www.youtube.com/watch?v=irqfGYD2UKw

How Does Sound Travel?

SOL 5.2

Sound

• Sound waves have to have a medium to travel through.

• Sound travels through liquids, solids, and gases.

The particles in a gas are the farthest apart.The particles in a solid are the closest together.

ExperimentTime!

Sound Vs. States of Matter

• Which state of matter does sound travel the fastest through?

• Solids• Which state of matter does sound travel the

slowest through?• Gas

• The farther apart the particles are, the slower sound can travel.

• The closer together the particles are, the faster sound can travel.

Uses and Application of Sound Waves

SOL 5.2

Humans

• We use sound for communication, safety, and music.

• We listen to the radio and TV to listen to music.

Can sound travel faster than the speed of light?

• http://www.youtube.com/watch?v=gWGLAAYdbbc

• Sonic boom: A shock wave of compressed air caused by an aircraft traveling faster than the speed of sound. It sounds like a loud, explosive sound, and it sometimes causes damage to structures on the ground.

Animals

• Most animals, like dogs and dolphins can hear higher pitches than humans, and from farther away.

• Animals use sound for communication, safety, and music too, but they have more uses.

Echolocation

• Some animals use echolocation, which is when animals make a high pitched sound (too high for human ears to even hear). They listen to their echo and use it to figure out how far away an object is, and how big an object is.

Echolocation

Echolocation