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Waves and Tides. Waves. Everyone has seen waves on a lake or ocean. But what are they? Waves are actually energy. Energy, not water, moves across the ocean's surface. http://www.virtualnjshore.com/tbwaves.html. Wavelength. Crest. Wave Height. Still Water. Trough. Wave Parts.
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Everyone has seen waves on a lake or ocean. But what are they? Waves are actually energy. Energy, not water, moves across the ocean's surface. http://www.virtualnjshore.com/tbwaves.html
Wavelength Crest Wave Height Still Water Trough Wave Parts
What causes waves? Waves are caused by energy being transferred into the ocean water The energy come from: • Wind- the wind is air that moves by energy from the sun. • Undersea Earthquakes- they can also put energy into the water
What determines the size of a wave? If waves carry energy, what has more energy, a big wave or a small wave? If winds cause waves, will stronger ,faster winds give wave more or less energy? (activity) If wind blows for a long time will the waves have more or less energy? If wind the wind blows over a small part of the ocean what will happen to the wave’s energy?
The size of the wave depends on the amount of energy transferred into the water. • The amount of energy depends on 3 things. 1. Speed of the wind 2. How long the wind blows 3. The distance over which it blows If any of these increases, the size of the waves will also increase
Storm Surge • A storm surge is a rise in sea level near the shore • It is caused by strong winds fro a storm like a hurricane. http://www2.sunysuffolk.edu/mandias/38hurricane/storm_surge_maps.html
Tsunami A tsunami is a powerful wave (or group of powerful waves) cause by the shaking of the ground under oceans. Earthquakes and volcanoes can cause tsunamis.
Effects of the Asian Tsunami In 2004, an earthquake occurred under the Indian ocean.
Wrap-up and Exit Ticket Word Bank: Waves, wavelength, crest, wave height, wave speed. Consists of a Trough and the distance between two of these is the Whose size determines Which is used to calculate
A tide is a rise or fall of the ocean’s surface Tides are caused mostly by the pull of gravity of the moon. The sun’s gravity also affects a tide just not as much as the moon’s High tide in Nova Scotia Low tide in Nova Scotia
Why we study tides Tides are important • When building beach properties. • Animals: Some animals like sea turtles only lay their eggs on certain tides (page 368) • Safety of humans • For Energy: Scientists can use movement of water during tides to produce energy (the enegery of the water powers generators to produce electricity)
Tides – how it works The moon can add to the pull of the sun and make higher tides. The moon can work against some of the gravitational pull of the sun and make the tides lower. http://curious.astro.cornell.edu/images/tides.jpg
High Tides High Tides occur when the oceans water has risen as far as it will go -This happens when the oceans on Earth are facing the moon
Low Tide • When the ocean water has fallen as low as it can go on shore • It happens when the moon is sideways from the shore
Spring Tide • During this tide the sun, moon, and Earth are aligned so gravity from the sun and moon pulls the oceans • This happens during a new moon or full moon.
Neap Tides • This is when the ocean levels on land are as low as they can go. • It only happens during a First Quarter new and a Last Quarter moon.
Tide Timing • The time between 2 high tides is 12 hours • The time between 2 low tides is 12 hours • There is a period of 6 hours between a high tide and a low tide