Can you hear me now?

Sound principles to live by....

https://www.youtube.com/watch?v=GkNJvZINSEY&feature=youtube_gdata

Sound occurs where there is vibrating matter!**Side Tracked... Review Time! **

Matter (exist in 3 states---solid liquid and gas)...and is anything that has mass and takes up space It can be observed to have characteristic or physical features that help define and describe the matter...

1. Luster ? ....shiny (metallic) or dull

2. Does it allow light to pass through?

Transparent...light passes through easily and you can see through it clearly

Translucent...light can pass through it but it looks cloudy or milky to the observer

Opaque... light can not pass through it... it bounces off this object...behind this object will be a shadow made from the absence of light

3. Hardness-Moh's scale....1 soft.....10 very hard

4.Density...How tightly the objects molecules are packed together...(mass packed in area of volume)Time to rattle your world!How come a 100 lb rock sinks and a 5000 lb log floats?

Answer…sinking and floating happen due to density and not because of weight

Sound must travel through matter because there must be vibrationThere are regions in the air where the air particles are compressed together and other regions where the air particles are spread apart. These regions are known as compressions and rarefactions

solid

Sound therefore moves the fastest through a solid and slowest through a gas because molecules are closest together in a solid and farthest apart in a gas...

liquid gas

Sound travels in waves....

A wavelength is measured from crest to crest..trough to trough....or starting point to starting point

Catching a WAVE

Sound waves travel in all directions at the same time---the puddle effect

sound

It's Batty but Sound BOUNCES !!!

Sound bounces best off of smooth flat surfaces that are hard...that is why you can hear a teacher's high heels in the hall. Soft surfaces that are irregular absorb sound and reduce any echoes

..

Humans and other creatures use sound waves to "see" their way through the world.

Echolocation--- bouncing sound off objects and using the echo (returning) sound to hunt and locate prey in the water or dark

Humans use ultra sound to see in the human body and we use sonar under the water

Frequency---How often a wave crest goes by in a specific amount of time

Short wavelengths = high frequency = high pitch or high sounding (violin)

Long wavelength = low frequency =low pitch or low sounding (cello)

How do you produce high frequency or pitched sounds?The rule: the faster an object vibrates the higher the pitch---so1. the tighter the string the higher the pitch2. the shorter the string the higher the pitch3. the thinner the string the higher the pitch

Just the opposite is also true: the slower an object vibrates the lower the pitch---so1. loosen the string2. lengthen the string3. thicken the string

Frequency is measured in Hertz...vibrations per second.

Humans can hear 20 hertz to 20,000 hertz...bats using echolocation can hear up to 120,000 hertz

http://en.wikipedia.org/wiki/Doppler_effect

The Doppler effect...the pushing and pulling of sound

https://www.youtube.com/watch?v=YTZcSaPn92s

Loud and soft sound are determined by the amount of energy used to create them

loud

soft

A sounds loudness is measured in decibels

The more energy put into the sound the louder its amplitude or loudness

SO......closeness of wave = frequency(pitch)

lowhigh

height of wave = amplitude(loudness)

loud soft

Sound can have pitch and amplitude

Loud and high pitched

loud and low pitched

soft and high pitched

soft and low pitched