Did you hear that SOUND

1
Did you hear that SOUND?

• Sound is a form of energy
• that travels in
• waves.

2
What makes Sound?

• 1. Vibration back and forth motion
• There can not be sound if there is not any
  vibration
• Most vibrations are too fast for you to see.
• Vibrations require energysound is a form of
  energy.

3
How does Sound Travel?

• 2. When something vibrates molecules in the air
  crowd together, then spread apart, causing sound
  waves to travel away from the vibrating object

4
What Forms of Matter can Sound Travel Through?

• Gas sound travels easily through gases
• It travels about 1,129 feet per second through
  air. (Thats how fast it travels when you talk!)
• Liquids Sound travels through water about 4,794
  feet per second. (Think of what ripples look
  like in the water and how they spread.)
• Solids Sound travels through a solid like wood
  at a rate of 12,620 feet per second. Sound
  travels fastest through solids!
• Sound cannot travel through a vacuum (a space
  that is empty of matter).

5
Sound Reflection and Absorption

• Reflected sound is called an echo.
• 1. The vibrations are reflecting back to
  you.
• Soft, air-filled objects absorb sound.
• 1. When sound is absorbed, you do not
  hear it because it is not reflected back to
  you.

6
1. Sound Waves

• Sound vibrations occur in waves that go out in
  every direction like a circle.
• 1. Sound waves are created by repeated
  patterns of molecules spreading apart and
  squeezing together.

7

• Sound Waves have 3 common features
• 1. They
• a. Have a set wavelength
• b. Vibrate at different speeds
• --Frequency the number of complete
  wavelengths, or times an object vibrates per
  second.
• c. Carry Energy
• --amplitude is the amount of energy a
  wave has
• --high amplitude sound is made by
  objects with great vibrating motion

8
Pitch

• 1. Pitch how high or low a sound is
• The higher the pitch the more squeezed together
  the waves are
• The higher the pitch the higher the frequency
• The lower the pitch the lower the frequency

9

• Making and Hearing Sounds
• 1. Hearing Sound
• a. Humans have two ears on opposite sides of
  their heads. Each ear gathers sound waves on
  each side of your body.
• b. There are two ways that humans hear sounds.
• With your ears.
• With your brain.

10
How do you hear sound?
1. Sound causes your eardrum to vibrate. The
eardrum vibrates differently for each sound.

• The bones of your ear begin to vibrate,
• beginning with the hammer, moves to the anvil,
• and finally the stirrup.

• The sound energy passes to the inner ear.
• This causes the fluid in the cochlea to move.

• The nerves then carry the message to the
• brain.

5. Your brain then tells you what the sound is.
11

• Making Sound
• All sounds are made by vibrations.
• Humans make sound waves by using their voice.
• The human voice is also made by vibrations.
• The source of sound in humans is the vocal cords.
• Vocal cords 2 thin, elastic, bands of tissue
  that vibrate to produce sound.

12
How do the vocal cords produce sound?

• Air from the lungs flows through the windpipe and
  into the voice box (where the vocal cords are).
• 2. Then the air pushes the vocal cords apart
  making them vibrate.
• 3. The vibrations create a series of sound waves
  that exit through your mouth.
• 4. The change of shape of the vocal cords
  changes the sound and its pitch.
• 5. If you cant talk because of a cold or
  laryngitis, it is because your vocal cords are
  swollen and inflamed.

13
Communication tools that use sound

• Voice allows you to communicate with others.
• Morse Code code for numbers and letters using
  sound
• Sonar a device that sends sound waves through
  water to measure or find something.
• Animal sounds
• Musical instruments