The currents of the ocean directly influence the climates on land. There are numerous currents in the ocean that change the temperature, making places such as the United Kingdom and Hawaii more temperate than they would otherwise be. Teach kids about this by filling a deep, thin glass dish like a bread loaf dish with oil. Add flaky spice like dried oregano or thyme and stir the spice in until it is evenly distributed. Place the dish on two mugs placed upside-down. Put a can of lit methanol gel under the dish and allow the oil to heat for a few minutes. Observe the spice flakes as they begin to move in a current of heated oil. This movement is thermal convection and is the principle that causes the currents in the oceans.
Create a diorama of the ocean to illustrate the wealth of life that inhabits it. Turn a shoe box on its side and remove the lid. Paint the back, top and sides of the shoe box blue and the bottom tan. Cut out sharks, fish, stingrays, octopus, squid and other sea creatures from construction paper and hang these on strings attached to the top of the shoe box. For older kids, encourage them to place the sea creatures in the box at the same level of the ocean where they would normally be found. Some creatures inhabit the sea floor, while others remain near the surface.
The ocean is full of sharks, but different types of sharks inhabit different areas of the ocean. Ask kids to use the Internet to find out where certain types of sharks live. Create a display using a large piece of piece of paper. Draw the continents on the paper and label the oceans. Put stickers on the paper for each type of shark to show where they are typically found, using a different color or shape of sticker to represent each different species of shark. This project can be done using dolphins or whales, if desired.
Experiment with water salinity by adding salt to a liter of water. Start with tap water, which has little natural salt in it, depending on where you live. Research the salinity of different bodies of water and add salt accordingly. The average salinity of the ocean is about 35 grams of salt per liter of water. Use this project to show kids the difference between the ocean, freshwater lakes and inland seas such as the Dead Sea.