1. Did you know that many creatures in the ocean have calcareous or silica shells and skeletons. When they die, their remains sink and accumulate on the ocean bottom. 2. Did you know that the limestone and chalk rocks are collections of millions of skeletons - a piece of chalk for writing on a blackboard probably contains a quarter of a million shells? 3. Did you know that larger creatures, such as algae, mollusks, sea urchins and corals, also form limestone? 4. Did you know that although the carpet of sediment on the ocean floor is sometimes 750 -1,000 meters thick, the rate of accumulation is very slow? 5. Did you know that in the Pacific and Indian Oceans, the rate is between a millimeter and a centimeter per 1,000 years? In the Atlantic, it is one to ten centimeters every 1,000 years. 6. Did you know that the Pacific Ocean is the largest and the deepest ocean on Earth? It was formed when the super continent Pangaea broke up. 7. Did you know that more than half of the people on Earth live along the shores of the Pacific Ocean? Did you know that the oldest parts of the Pacific Ocean are about 135 million years old? 8. Did you know that the Pacific Ocean is decreasing in size as continental plates move together? At the same time, the Atlantic Ocean is becoming larger. 9. Did you know that the Mariana Trench, in the western Pacific Ocean, is the deepest oceanic trench in the world - 36,201 feet (11,034 meters) deep? 10. Did you know that the water in the oceans differs from pure water in that seawater has substances dissolved in it? The two most abundant elements in seawater are sodium and chlorine, mostly combined in the form of sodium chloride (common salt); the presence of these elements is the reason for the salty taste of the sea. 11. Did you know that sodium and chlorine, together with four other elements - magnesium, Sulphur, calcium and potassium - make up about 95 per cent in weight of the substances dissolved in seawater?