Why is the ocean blue. No one knows for sure Why is the ocean blue? No one knows for sure. There are several theories as to why the ocean is usually blue. Some scientists believe that when sunlight hits seawater, part of the white light is absorbed and part is reflected. White light is composed of various shades (all the colors in the rainbow). Seawater does not absorb blue light, so the blue light is reflected outwards. Some scientists believe that suspended matter in the sea is responsible for its blue color.  What causes waves?  Wind is the most common cause of surface waves. The longer the distance a wind blows, the stronger it is, and the bigger the waves. As wind blows over the ocean, it tries to pick up some of the water. Because the surface of the water can not move, it rises. Gravity pulls the wave back down into the ocean. However, the water now has momentum. Water pressure from below pushes the water back up, and the cycle starts again. 

Why is the ocean salty. It is salty because it has a lot of salt in it Why is the ocean salty? It is salty because it has a lot of salt in it! Salt is a mineral that is found in soil and rocks, too. Flowing water picks up some salt and carries it to rivers. Rivers carry it to seas. Since this has been happening for millions of years, the oceans now have a lot of salt—about one cup per gallon! Where is the deepest part of the ocean? The deepest place is near the Mariana Islands in the Pacific. The water is over 36,000 feet deep in the Mariana Trench. That's over 7 miles deep. Mount Everest is only 6 miles high!

The Oceans… The Pacific Ocean is the largest covering 166 million square kilometers (64 million square miles) of the surface with an average depth of 4200 meters (14,000 ft). At nearly half the size, the Atlantic Ocean occupies 83 million square kilometers (32 million square miles) with an average depth of 3900 meters (13,000 ft). With a similar average depth, The Indian Ocean is slightly smaller at approximately 73 million square kilometers (28 million square miles).

The Oceans… The Southern Ocean surrounds Antarctica and was recognized in 2000 as an ocean by the  International Hydrographic Organization. It encompasses roughly 20.3 million square kilometers (7.8 million square miles) with a typical depth between 4,000 and 5,000 meters (13,000 to 16,000 feet). The Arctic Ocean is the smallest covering 13 million square kilometers (5 million square miles) with an average depth of 930 meters (3250 ft). Some view the Arctic Ocean as a sea rather than ocean because of its small size.

The Seas… Seas are salt-water bodies smaller than oceans and partially enclosed by land. Major seas include the Mediterranean, Baltic, Bering, Black, Caribbean, Coral, North, Red, and Yellow. Unlike inland lakes that can be salt or fresh water, there is a constant exchange of water between ocean and sea. Several inland salt lakes like the Aral, Caspian, and Dead are erroneously named "seas".

What do We Know? At it’s surface the ocean is in constant motion with powerful currents that stretch for thousands of miles and towering waves. Beneath the ocean’s surface lie hidden mountain ranges, vast trenches tens of thousands of feet deep, immense hot springs, and huge volcanoes spewing molten rock in massive eruptions.”

Why Study the Ocean? Major Influence on weather and climate Source of food, energy, medical drugs Important in transportation Military Significance Recreational resource Major influence on the health of the planet Culture and history Highly topical-El Nino, Tsunami, global warming, sea level rise