Waves

• Waves are energy.• Energy, not water,

moves across the ocean’s surface.

• The best way to understand waves as energy is to think of a long rope laid on the ground. If you pick up one end and give it a good snap -- there's a ripple effect all the way to the other end -- just like the waves on the ocean!

• That means that energy is applied at one end and it moves to the other end. The energy is released at the other end of the rope, just as the energy of waves is released on shores.

Parts of a Wave

Parts of a Wave

Frequency

• Frequency- The number of waves made per time interval.

• Usually measured in cycles per second (Hertz)

• 1 Hertz = 1Hz

• If 10 waves are made per second, the frequency is said to be 10 Hz.

What determines Wave Height?

• Most waves are generated by wind:– 1. Wind speed– 2. Wind duration– 3. Fetch

• The distance the wind blows uninterrupted over the sea surface.

• An unusually large wave surrounded by smaller waves.

• Over 40 feet high.

• Often come from directions different than prevailing wind and waves.

• Occur over the deep ocean.

• Especially dangerous to sailors and fishermen in small ocean vessels.

• Generally dissipate before reaching shore.

• Triggered by underwater seismic movements (earthquakes, volcanic eruptions), landslides, or avalanches.

• They may be less than 2 feet high in the open ocean, but they travel at 500 km/hr and can be 160 km long.

• When they come ashore the wave shortens and gets very tall.