You don't always have to dive to learn about the ocean.
Ocean water encompasses 71 percent of the planet's surface and supports nearly half of all life on Earth. Humans still haven't explored over 95 percent of the ocean habitat. Oceanography is the scientific study of the world's oceans and seas; it is also sometimes referred to as oceanology. There are many different aspects of oceanography. Oceanographers learn about the diverse forms of marine life and the geography of the ocean floor.
Freezing Point
Fill two clear plastic cups halfway with water. Measure out four tablespoons of salt and pour it into one cup. Write the word "salt" on this cup with a marker. Set the cups in the freezer for one hour. Inspect the cups every hour for four hours and note the change that occurs between the cups. Allow the cups to sit in the freezer overnight and inspect them again in the morning. The salt water won't freeze as quickly as regular water, because they have different freezing points.
Density
Use food coloring to reveal the differences in density between salt water and fresh water. Compare the initial density of a salt solution and fresh water with a hydrometer. Use food coloring to dye the salt solution and fresh water different colors. Look for color changes and schlieren lines where the solutions mix. Measure the density. Repeat the experiment twice, then invert the fresh water over the salt solution three times. Test temperature's effect on density using bottles of colored hot and cold fresh water and a thermometer. Warmer water is less dense and increased saline concentration makes water denser.
Depth and Pressure
Punch holes up the side of a paper cup and cover the holes on the outside of the cup with a strip of masking tape. Set your cup in a sink or outside and pour water into it continuously. Observe how far the water goes as it leaves each hole. The deeper water leaving the bottom hole goes farther because it is under more pressure. The water pressure increases with depth because the weight of the water is pushing down from the top of the cup. This is why deeper ocean water is under greater pressure than shallow water.
Ocean Floor Models
Make a model of the ocean floor inside a shoe box with sand or gravel used for fish tanks, pictures painted on poster board of marine animals, and tissue paper coral and seaweed. Make the model more impressive by making alternating folds and slits of different lengths in the shoe box to show the effects of sea floor spreading and the collision of tectonic plates.
Tags: fresh water, salt solution, cups freezer, food coloring, learn about, Make model, ocean floor
