Students can learn about science concepts such as density and buoyancy by designing their own submarines that float and sink. Although real submarines are made of steel, they float because the air inside compartments, or ballast tanks, makes the vessel less dense than water. When the ballast tanks empty of air and fill with water, the submarine becomes denser than water and sinks. Students can design and create their own plastic bottle submarines or follow instructions from designs on the Internet. Simple designs include medicine dropper and pen cap contraptions inside water-filled bottles. For more complex designs, students can drill holes in the bottles and add tubing, coins, marbles, balloons, straws, tubing or paper clips. They can carve propellers and fins from the bottoms of plastic bottles.
Students can make submarines with ingredients in the kitchen cabinet and refrigerator. Cut a baby carrot, small potato or celery stalk into the desired submarine shape. Insert toothpicks to adapt the buoyancy of the submarine if necessary. Carve out a small hole on the underside of the vegetable and pack with baking powder or an effervescent antacid tablet. When the baking powder or antacid is submerged in water, a chemical reaction will occur. The chemical reaction will create fizzing bubbles that will cause the vegetables to rise and sink repeatedly.
Dutchman Cornelius Drebbel is credited with building the first submarine, a decked-over rowboat, in 1623. Today, submarines have evolved into nuclear-powered steel vessels, longer than two football fields. Students can research the history of submarines. Using their own drawings or computer graphics, they can make timelines that show the history and evolution of the submarine.
Seventh graders can read a classic submarine novel like Jules Verne's "20,000 Leagues Under the Sea" and create dioramas that depict scenes from their chosen books. There are a variety of ways to make a submarine diorama. Students can make a shoebox diorama and practice math skills by making three-dimensional objects to scale. Students could make their dioramas larger and in the shape of a submarine.
Students can recycle and make a submarine craft at the same time. Instead of throwing away household items like paper roll tubes and egg and milk cartons, students can salvage them to make submarines. First, students should familiarize themselves with the parts of a submarine. Then they can recycle household objects that can simulate the parts. Students can describe why they chose certain objects to represent different parts.