Waves are periodic, meaning they are disturbances of
energy which repeat.
1 Cycle
Successive identical parts of a wave is a cycle, or λ
The time it takes for one cycle is a period or T
Frequency is cycles per second.
f =1
T
A wavelength (λ) is a cycle.
λ is usually crest to crest.
A wavelength (λ) is a cycle.
But λ can be any two successive identical points on a wave.
Sound is vibrations which create compressions in the
air.
These compressions travel to our ear drums where we
experience sound.
High frequency waves have a high pitch.
Low frequency waves have a low pitch.
This is best observed in the Doppler Effect.
When wave source is moving waves are high frequency in
front of the object.
When wave source is moving waves are low frequency in
behind the object.
A wave on a string moves faster the more tension the
string has on it.
Just like compressions move through a slinky faster when
the coils are tighter..
Remember…..• v = λf or v = λν• The frequency of a sound wave determines the pitch of the sound.• High frequency = High pitch• Low frequency = Low pitch• The loudness of sound is determined by the amplitude. • More amplitude (thicker compression) means louder sound.
Sound moves faster through warmer air because the
molecules in warmer air are moving faster.
Medium Speed of Sound
Air at 0°C 331 m/s
Air at 20°C 343 m/s
Sound moves faster through more dense matter and slower