Coastlines

Coastlines By: Alli, Rebecca, Jordan

= The ocean is an amazing part of the world and can be very beautiful, and the waves could one day be beautiful and very calm and the next there could be a tsunamis. But what makes these waves? Why are there beaches and bays? How did the wholes get in the rocks at The Bay Of Fundy? Why are there tides? Read on and all of these question and many more will be answered! Enjoy and learn lots! = Wave Energy And How Waves Work You can measure the height of a wave by starting at the crest, (the highest point of the wave) to the trough (the lowest point of the wave). The way to tell the length of the wave is by measuring the wavelength. The wavelength is the space between one crest and the next. Scientist can find the speed of a wave by the time made for a wave to get to a certain spot. Waves are made by a movement somewhere in the ocean or on the ocean floor. It could be wind, an earthquake, a volcano eruption, hurricane, or landslides. Waves from the ocean are just very large ripples made in the ocean like when you blow in a bowl of soup, in a glass of water or if u drop a rock in the water. How height the waves are depends on how fast it is going, or how long it has been moving. When there has been a hurricane the height of a wave could be up to two thirds of the height of Niagara Falls! On a clam day there are still waves but they are much smaller than on a windy day. They are called swells; these waves are made from very small winds out at sea or a storm that has happened very far out at sea. When a wave reaches the shore it changes its shape and it slows down due to friction. Although the crest of the wave stays going at the same speed, the wavelength shortens and the height of the wave grows. The crest of the wave starts to outrun the trough and falls forward. The wave falls on to shore. This is called a breaker.

How Waves Change The Shore Line Waves change the shape of the coast lines. They erode the beaches and wash away the sand and rocks. Some coast lines the waves are hard, fast and flow around the rocks. Other coast lines the waves are soft and slow and flow along the soft sand. Some beaches have soft sand and others have hard rocks, but why is that? It is because of the kinds of rocks, how they were made, and how much erosion there has been. It is also because of the shape of the coast lines. A headland is when the land sticks out in to the ocean; the ocean waves hit the headlands first. The spot where the land goes in after the headlands is called a bay. The waves hit the rocks on the headlands with a speed up to thousands of kilometers per square meter. This hard hit of the waves breaks of parts of the rocks, that forms cliffs by the ocean. After the waves hit the headlands they lose most of their energy and slow down to go in the bays. At the bottoms of these cliffs that the waves make there are little rocks and they float around in the waves and break off more rocks and they remove loose rocks on the cliffs. After a long time the waves erode a lot and sometimes they might make the rocks hollow, like some rocks at the Bay of Fundy. Also sea water can dissolve minerals in rocks and that can make them hollow to. This process is called erosion.

How Beaches Are Formed A beach is a big deposite of sediment that runs along the whole coastline. The sand on the beach is made up of grains of sand that came from erosion which would have taken place under the water. If the erosion gave off coal, then that determines the color of the sand; which would be black. The most common sediments are known to be fragments of hard minerals; quartz. Some beaches have barriers that can be used, and are used along shorelines to protect the beach from erosion.

Waves continue to change the way they move, which makes the beach in a constant state of change as well. When the waves rush onto land, it is known to bring different objects from the water, such as shell or coral from the bottom. In the winter, the strong winds crash onto the land which is much more stronger, and it can remove a lot of sediment from the beach (more than it puts onto the land). Along some coastlines, there's a zigzag shape that forms a series of bays (parts of the ocean that reach into the land) and headlands (areas of the land that stick out into the sea).

Tides Even though the sun has a much more powerful gravitational pull than the moon, the moon is much closer than the sun to the earth which makes its gravitational pull two times more effective than the sun’s.Beaches can be covered by water, and sometimes they aren’t. The reason for that is the tide. The tide is the gravitational pull from the moon, causing the water to rise or go low.

When the water on a beach is classified as “high tide” you might think the volume of the water increases, but it doesn’t. Water from the other pushes to make one side higher than the other. The largest tidal movement is called spring tides and that occurs when the Sun, Earth and Moon are in a line. The smallest tidal movements are called neap tides and that occurs when the Moon and Sun are right angles to each other. Knowing that the moon pulls the water, it creates a bulge in the water, so technically it’s higher than what it really is when the high tides are in on one side. It’s said that centuries ago people have realized about the cycle for the tidal waves and movement had something to do with the movement of the moon.

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True or false ~ 1. You can measure the height of a wave by using a measuring tape. 2. Waves are started by any type of motion anywhere in the ocean. 3. A wave is called a cracker when the wave falls to shore. 4. Some beaches are made of rocks while others are soft sand. They are like this because of the wind. 5. Some beaches have things called breakers that protect the beaches from erosion. 6. The tide is caused by the way the earth moves. 7. When the beaches are covered by water of not covered it is called tides. 8. When it's high tide the water is deeper than it is on low tide.

Answers!! 1. False  2. True  3. False  4.False   5.False   6. False  7. True  8. False

 Reference List

Clancy, Christina. //Sciencepower8//. Toronto: McGraw Hill Ryerson, 1999. Print. "Dirtmeister's Science Lab." //Dirtmeister's Science Lab//. N.p., n.d. Web. 17 May 2012. "Beach Basics | Coastal Care." Beach Basics. N.p., n.d. Web. 15 May 2012. < http://coastalcare.org/educate/beach-basics/ >. Wave: "Google Images." Google Images. Web. 29 May 2012. Wave diagram: "Google Images." Google Images. Web. 01 June 2012. Ripple: "Google Images." Google Images. Web. 29 May 2012. Wave diadram 2: "Google Images." Google Images. Web. 29 May 2012. Bay: "Google Images." Google Images. Web. 29 May 2012. Beach: "Google Images." //Google Images//. Web. 01 June 2012. . Tide diagram: Web. 1 June 2012.