VIBRATION Sound and Noise

Musical Sounds Musical sounds provide relaxation and pleasure. These are regular patterns. Sounds that can be resaved on to recordings.

Noise Loud irregular patterns are called NOISE. Prolonged periods of loud noise (irregular patterns of sound) can cause temporary or permanent loss of hearing.

Sound Travels Through Gases (air) Liquids (sound travels 4 times faster through liquid than it does through air) Solids (sound travels the fastest in solids because the molecules are packed tightly together)

Outer Space Sound cannot travel through outer space because there are no air molecules to carry the sound waves.

How We Use Sound Instruments Speech Bells

Vibration Sounds from doors closing, ball bats hitting the ball, dogs barking and musical instruments are made when matter vibrates, or moves quickly back and forth. Vibrations can be made from: Blowing Stroking Plucking Striking

Pitch Pitch is the highness and lowness of sound. When you blow air into the (large) tuba, the air vibrates slowly. The sound waves have long wavelengths, and the sound has a low pitch. When you blow air into the (small) piccolo, the air vibrates quickly (fast). The sound waves have short wavelengths, and the sound has a high pitch.

SOUND WAVES Experiments Make a big bang by bursting an air-filled paper bag. The air trapped inside the bag will send a powerful sound wave through the air that reaches our ears. Set up a row of dominoes by spacing them fairly close. Knock the first one over and watch how the wave travels. Sprinkle a few grains of uncooked rice on a paper and lay that paper over a radio and watch the rice jump as you turn up the sound. Place a ruler on the edge of a table and bend the ruler. Watch the ruler vibrate. Try changing the length that is over the edge. The shorter the length, the quicker the vibrations, the higher the sound. The number of sound waves a second is called the frequency of waves.

Feeling Sound When something is making a steady sound then it must be vibrating to push the air back and forth. Place your hand On a purring cat On a ringing telephone On a radio or speaker that is playing loud music On your throat and count to ten

ASSESSMENT You hear sound through your________________. Sound is made when matter ____________. Objects that vibrate slowly have a pitch that is ____. Objects that vibrate fast have a pitch that is _____. Sound moves the fastest through ______________. Sound moves the slowest through _____________. Sound travels through all forms of _____________. Sound travels louder through _______ than air.