The sea is the most obvious feature of the earth's
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The sea is the most obvious feature of the earth\'s surface. Approximately seventy percent of this surface is covered by water, in one way or another. Beneath this water are the familiar sands of the beaches, bottoms of bays, and the inshore ocean. Farther offshore this water covers an amazing submarine topography of underwater canyons, trenches, mountains, and plains. Unlike the continents, which are physically separated from one another, the oceans are continuous and interconnected. Since the "world ocean is continuous"(M.J. Keen) it has similar characteristics throughout. In the early 1870s oceanographers collected seawater samples from all of the seas of the world at a variety of depths. When analyzed, the samples were found to have quite similar characteristics. These findings convinced many that a method of study was needed. The study of oceans was named oceanography.
Density, salinity, and temperature are very important concepts in the study of oceanography. The salinity and temperature of the water influence its density, and the differences in density are the major factor in understanding the formation of currents and the positions of water masses in the sea. In addition, temperature and salinity play major roles in influencing the distribution of plants and animals.
The sediments of the sea floor may be divided into lithogenous, hydrogenous, biogenous, and cosmogenous sediments. Lithogenous sediments are the major sediments on the ocean floor. They are derived from the chemical and mechanical weathering of rocks. Biogenous sediments are composed primarily of the protective outter covering of small marine animals and plants. If these remains comprise at least thirty percent of the sediment it is called an "ooze". "Oozes" were named for the types of organisms that formed them. Hydrogenous sediments form as a result of the chemical reactions that occur in the seawater. These reactions result in the formation of small particles, which are deposited on the sea floor. Currents move these particles and cause them to collide with the other particles. If many of these collisions occur they may form nodules. Nodules are found on some portions of the deep-sea floor. The sediment type frequently determines the type of organisms that will be found in that specific area.
"Waves are variable and transitory features of the sea\'s surface." (Sandra Smith) All waves, from the smallest ripple to the most destructive tsunami, have common characteristics. They all have crests, troughs, wave heights, lengths, and periods. Also, water particles that make up the waves all move in identical orbital patterns. The orbital pattern is up and forward in the crest and down and back in the trough. It is only when the wave becomes unstable that the orbital motion is destroyed. The water particles then begin to move at the same speed as the moving wave form.
Breaking waves release a tremendous amount of stored energy on a beach face. This energy moves the sand about and changes the configuration of the bottom. As the bottom configuration is changed by the waves, it changes the characteristics of incoming waves. This interaction between the waves and the bottom results in the beach face having an everlasting wave pattern.
Everything in the universe is composed of extremely small paritcles called atoms, which are often bonded together to form molecules. Molecules are formed as the result fo the transfer of electrons between atoms. The complete loss and gain of electrons results in the formation of ionic molecules, which have completely positive and negative vegions. Unequal sharing of electrons, on the other hand, characterizes the polar covalent molecules, which have only partially positive and negative regions. The equal sharing of electrons result in the formation of nonpolar covalent molecules, which do not develop charged regions.
Due to the development of charges on ionic and polar molecules, intermolecular attractive forces form between these molecules, intermolecular attractive forces form between these molecules and enable the compounds to exist in the solid and liquid state. Ionic compounds have long-range order and exist as solids. Polar covalent molecules are liquids because of their short-range order, while the nonpolar gases do not develop intermolecular attractions and as a result exibit no order.
Changes in state are due to a change in the order of compounds. When energy is added, molecular motion increases and intermolecular attractive forces are disrupted. This results in the melting
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