1. WAVE INTERACTIONS

2. Waves transfer energy without transferring matter.

3. Mediums Most waves require a medium to travel through.
These are called Mechanical Waves.
A medium is any matter that a wave travels through.

4. Electromagnetic Waves
Any wave that does not need a medium to travel through is called an electromagnetic wave.
Although we now have gravity waves……..that are not technically electromagnetic.

5. Longitudinal Wave Compressional Wave wave particles vibrate back
and forth along the path that
the wave travels.
Compressional Wave

6. Compressions
The close together part of the wave
Rarefactions
The spread-out parts of a wave

7. Transverse waves
wave particles vibrate
in an up-and-down motion.

8. Transverse waves Crests Highest part of a wave Troughs
The low points of the wave

9. Amplitude-
is the maximum distance
the particles in a wave
vibrate from their rest positions.

10. Wave Length
For a transverse wave the wave length is from one crest or trough to another.
For a longitudinal wave a wave length is from one compression or rarefaction to another.

11. Period and Frequency
Period
the time required for one full wave length to pass.
It is represent with T.
And is usually measured in seconds

12. Represented by a lower case f Units are measured in Hz
Frequency
- the number of waves produced in a given time (usually 1 second).
Represented by a lower case f
Units are measured in Hz

13. Wave Velocity - is the speed with which a wave crest passes by a particular point in space
It is measured in meters/second.
Wave Velocity = Frequency  Wavelength

14. Speed of Sound air (0 C) 331 water (25 C) 1493 sea water 1533
Medium velocity m/sec
air (20 C)
air (0 C)
water (25 C)
sea water
diamond
iron
copper
glass

15. The Type of Wave Matters
The type of wave also determines the speed.
Electromagnetic waves do not need a medium.
All electromagnetic waves travel through a vacuum at c = x 108 m/s.
Put them in a medium and they get bounced around.

16. Doppler Effect How a wave sounds (pitch) depends upon the frequency.
Meaning the more waves pass by in a second the higher the pitch.
This can be created by the Doppler effect.

17. II. Properties of Sound

18. - description of how high or low
Pitch
- description of how high or low
the sound seems to a person
. Loudness-
how loud or soft a sound is
perceived to be.

19. Loudness of Sound in Decibels
Loudness (dbs)
Hearing Damage
Average Home
40-50
Loud Music
90-100
After long exposure
Rock Concert
Progressive
Jet Engine
Pain

20. Ultrasound Infrasound Sounds in the range from 20-100kHz
- sound waves with frequencies above the normal human range of hearing.
Sounds in the range from kHz
Infrasound
- sounds with frequencies below the
normal human range of hearing.
Sounds in the Hz range

22. Interference
the result of two or more sound
waves overlapping

23. Different sounds that you hear include
(A) noise, (B) pure tones, and (C) musical notes.

25. Standing sine wave patterns of air vibrating in a closed tube
Standing sine wave patterns of air vibrating in a closed tube. Note the node at the closed end and the antinode at the open end. Only odd multiples of the fundamental are therefore possible.

26. Standing waves in these open tubes have an antinode at the open end, where air is free to vibrate.

27. Standing sine wave patterns of air vibrating in an open tube
Standing sine wave patterns of air vibrating in an open tube. Note that both ends have anitnodes. Any whole number of multiples of the fundamental are therefore possible.

28. Doppler Effect is the apparent change in the
frequency of a sound caused by
the motion of either the listener
or the source of the sound.

30. Sounds from Moving Sources.
A moving source of sound or a moving observer experiences an apparent shift of frequency called the Doppler Effect.
If the source is moving as fast or faster than the speed of sound, the sound waves pile up into a shock wave called a sonic boom.
A sonic boom sounds very much like the pressure wave from an explosion

31. Supersonic Flight

33. Resonance exactly matches the natural frequency of an object.
the frequency of sound waves
exactly matches the natural frequency
of an object.

35. Water Waves

36. Tsunami
Wave length, 500 to 600 km in ocean

37. Tsunami Warning
On December 26, they were playing in the sea when Tilly suddenly found the water was bubbling, like on top of a beer. She immediately realized tsunami was coming because the scene reminded her of a geography lesson about Hawaii's 1946 tsunami.
Right away, Tilly told her parents, sister and other tourists to escape quickly, but at first they were in half belief. However, seeing Tilly's serious and firm expression, people started to be convinced of the seriousness of the thing and instantly left the beach.
At last over 100 tourists were ended up in safety with no death