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Presentation on theme: "Waves."— Presentation transcript:

1 Waves

2 What is a wave?  - a repeating disturbance or movement that transfers energy through matter or space Examples: ocean waves light sound

3 Waves travel through matter - this is called the MEDIUM
Mediums can be - solid  (earth) - liquid (water) - gas  (air) Light and radio waves travel through space and do not need a medium.

4 Movie Trivia. Each of these has something to do with waves
1.  This movie from 1991 stars Keanu Reeves and Patrick Swayze as a pair of surfers who also rob banks. 2.  In 1998, a meteor hits the earth and creates a huge wave.  The tagline for this movie was "The coast is toast."

5 Transverse Waves - medium moves at a right angle to the direction of the wave (like in the ocean)
Compression waves - medium moves along the same direction as the wave, visualize a coiled spring.

6 Sound waves are compressional waves caused by air molecules vibrating, like when a door slams
Sound waves can also travel through other mediums, like earth and water       

7 RAREFACTION = area of wave where it is less compressed
You can use a Slinky to get a good idea of how compressional waves, such as sound, move. Stretch a Slinky out and then give one end a good strong knock or jiggle. This will push the coils near your hand into the ones next to them, which will be pushed into the next and the next and so on, all the way to the other end. At the other end, the compression will rebound and move back in the other direction. Thus a "compression" moves back and forth. RAREFACTION = area of wave where it is less compressed

8 Waves in the ocean start with WIND

9 Winds continue to push on the water and generate waves, the waves trap more wind and get bigger and bigger.  The size of the wave depends on wind speed. 

10 Shallow water causes wave to "break"
Other factors can reduce the size of a wave before it lands, such as reefs or islands. A steep drop off will make a larger wave.

11 The moon doesn't cause waves, but it does cause tides.
A tide is the rise and fall of the ocean and is based on the sun, moon, the earth's rotation

12 Wind and Rogue Waves, match these shipwreck / disaster at sea stories.
1. A rogue wave capsizes a cruise ship. People who survived must climb their way to the surface because the ship is floating upside down. 2.  Not caused by a wave exactly..but this ship was wrecked because it ran into a floating iceberg. 3.  Who was the Greek God who held dominion over the ocean and the waves? 4.  This villain's ship moved under the waves.   He chased Jack Sparrow throughout the second Pirates movie.  What as his name? The Poseidon The Titanic Poseidon Davy Jones

13 What is a rogue wave? Deadliest Catch Video
also known as freak waves, monster waves, killer waves, extreme waves, and abnormal waves are relatively large and spontaneous ocean surface waves that occur far out in sea. Deadliest Catch Video

14 We perceive these waves as earthquakes.
Seismic Waves - waves that occur on the crust of the earth.  They can cause structures to collapse We perceive these waves as earthquakes. Earthquakes can cause a TSUNAMI

15 Quick Review Type of Wave Where it Occurs What does it do?
Seismic Waves Sound Waves Rogue Waves Ocean Waves

16 The Parts of a Transverse Wave
The high part of the wave is the CREST The low part of the wave is the TROUGH Wavelength = the distance from one point of the wave to the next point

17 This is not on your notes...
Practice Labeling


19 Parts of a Wave as explained by surfers
What type of wave is best for beginners? _______________ What type is for experienced surfers? _________________

20 The Parts of a Transverse Wave
FREQUENCY =  number of waves that pass a point in a second Frequency is measured in hertz (Hz) Each wave has a PERIOD, which is the amount of time it takes for one wavelength to pass a point

21 This makes the wavelength SHORTER high frequency = short wavelength
If you make transverse waves by moving a rope up and down, you can increase the frequency by moving the rope faster. This makes the wavelength SHORTER high frequency = short wavelength low frequency = long wavelength

22 Wave Speed - how fast a wave travels
   Speed (m/s) =  frequency (Hz)  x wavelength (m) Greek letter lambda is used to represent wavelength

23 Wave Amplitude Amplitude is related to the amount of energy a wave carries. Tighter packed coils of the slinky will cause greater energy. In the rope, raising the hand higher and causing "bigger" waves increases the amplitude Amplitude = height of wave

24 QUIZ  TIME (only covers first half of notes)