Waves Waves n Rhythmic disturbances that transmit Energy
Waves
Waves n Rhythmic disturbances that transmit Energy n Information n n Waves are usually comprised of a higher-energy state followed by a n lower-energy state n n of a medium or an energy field
Two kinds of waves Classified by the motion of the medium compared to the motion of the wave n ACTUAL MEDIUM PARTICLES DO NOT CHANGE LOCATION!!! n
Two Kinds of Waves n Transverse (Sine) Waves Medium particles move at right angles to the wave direction n Water waves, wind waves, EM waves (radio, light, X-Rays, etc. ) n
Two kinds of waves n Longitudinal (Compression) Waves Medium particles move in the same direction as the wave n Sound waves, certain earthquake waves, springs n
Which kind of wave vibrates in the same direction as the wave? Transverse Wave Longitudinal Wave Seismic Wave Big Kahuna Wave 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Which of these can be transmitted by a wave? Energy Information Particles None of these 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
What name is given to the material through which a wave travels? Water Air Steel Medium 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Which kind of wave vibrates at right angles to the wave? Transverse Wave Longitudinal Wave Seismic Wave Big Kahuna Wave 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
A wave is a Motion on the ocean Amber unit of grain Non-verbal good-bye signal Rhythmic disturbance 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Which of these is an example of Compression or Longitudinal waves? Sound Waves Water Waves “The Wave” at Quest Field None of these 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Which of these is an example of Transverse waves? Sound Waves Cymbals Accordions Ultraviolet Light 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Participant Scores 700 600 Participant 12 Participant 14 Participant 2 Participant 3 600 600 600 500 Participant 7 Participant 8 Participant 13 Participant 16 Participant 23 Participant 1
PARTS OF A TRANSVERSE WAVE
Parts of a Transverse Wave n The Normal or Rest Position n n Crest n n Represents the “undisturbed” medium Point representing the highest energy of the wave Trough n Point representing the lowest energy of the wave
Properties of a Transverse Wave n Amplitude Distance from the normal or rest position to the crest or trough n “Height” of the wave n Represents the amount of energy in the wave n n Wavelength Distance from one point on the wave to the same point on the next wave n Distance of ONE FULL CYCLE of the wave n n Frequency Number of waves that pass a point in a unit of time n Measured in Hertz (Hz) for waves per second n
Parts of a Longitudinal Wave n The Normal or Rest Position n n Represents the “undisturbed” medium Compression Area representing the highest energy of the wave n Medium particles are pressed together, area of high energy n n Rarefaction Area representing the lowest energy of the wave n Medium particles are far apart, area of low energy n
Properties of a Longitudinal Wave n Amplitude How “tightly compressed” particles of the wave are n Represents the amount of energy in the wave n n Wavelength Distance from one point on the wave to the same point on the next wave n Distance of ONE FULL CYCLE of the wave n n Frequency n Number of waves that pass a point in a unit of time
What is the lowest energy area of a longitudinal wave called? Compression Medium Wavelength Rarefaction 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
What is the highest point of a transverse wave called? Trough Amplitude Crest Rest 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
What is the lowest point of a transverse wave called? Trough Amplitude Crest Rest 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Which describes how often a wave point passes a particular location? Compression Frequency Wavelength Amplitude 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
What is the horizontal line that represents an undisturbed medium? Trough Amplitude Crest Rest 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
What is the highest energy area of a longitudinal wave called? Compression Medium Wavelength Rarefaction 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Which of these represents the amount of energy in a wave? Trough Amplitude Crest Rest 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
What is the distance between one point of a wave to the same point on the next wave? Compression Medium Wavelength Rarefaction 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Participant Scores 0 0 Participant 1 Participant 2 Participant 3 Participant 4 0 Participant 5
Other Wave Properties n Period The time it takes for one complete wave cycle n Inverse of the Frequency n P = 1/f f = 1/P When the Period is in seconds (s) and the Frequency is in Hertz (Hz)
What is the frequency of a wave that has three waves in two seconds? 0. 67 Hz 5 Hz 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
What is the period of a wave that has three waves in two seconds? 0. 67 s 5 s 1. 5 s 1 s 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
What is the period of a wave that has five waves in three seconds? 1. 67 s 0. 59 s 0. 90 s 1 s 1. 2. 3. 4. 20 1 2 3 4 5 6 7 8 9 10 11 12 21 22 23 24 25 26 27 28 29 30 31 32 13 14 15 16 17 18 19 20
Participant Scores 0 0 Participant 1 Participant 2 Participant 3 Participant 4 0 Participant 5
Other Wave Properties n Wavespeed Velocity of a wave n Can depend on the medium n n Sound travels faster through dense mediums, radio waves can’t penetrate rock Wavespeed = wavelength x frequency = x ƒ Wavespeed is usually in m/s when wavelength is in m and frequency is in Hz (1/s)
More on Wavespeed n All EM waves travel at the Speed of Light Symbol: c n Value: 186, 282. 6 miles per second n 299, 792, 458 m/s n n This is currently the fastest speed in the Universe
So conversions on c are easy… = = ƒ= x ƒ and c = c ÷ ƒ c ÷ x ƒ
Watch for these conversions! 1 m = 10000 nm (nanometers) 1 nm = 1. 0 x 10 -9 m Light vibrates in the nm and ångström ranges 1 m = 100000 Å 1 Å = 1. 0 x 10 -10 m
- Slides: 40