Submarines are vessels that have the ability to travel underwater. With the physics principles of density and buoyancy, they can float or sink. The first military submarine, the Turtle, was built during the American Revolution (1775-1783). During World War I and World War II, the submarine played an important part in naval warfare. Other than military warfare, submarines are used in research and occasionally in tourism.
2) Submarine Basics
Submarines typically have a hull, sail, rudder, propeller, sail and stern planes as well as ballast tanks.
The hull, also known as a pressure hull, keeps water from entering the inside of the submarine. It also helps the submarine to withstand the extreme water pressure in the depths of the sea.
The sail contains equipment such as the periscope, radio antenna and sail planes.
The rudder helps to steer the submarine left and right.
Lastly, the propellers help to drive the submarine forward.
The ballast tanks help the submarine to control its buoyancy. Air is less dense than water. Therefore, the submarine will float when its ballast tanks are filled with air. However, when the ballast tanks are filled with water, the submarine becomes denser and it sinks.
3) Forces and other design consideration
Some of the forces acting on submarines are buoyant force, gravitational force, engine force and water resistance.
Buoyant force is the upward force acting on the submarine. On the other hand, gravitational force is the downward force acting on the submarine. Both engine force and water resistance are forces that only occur when the submarine is moving. Engine force is the force that propels the submarine forward. Finally, water resistance is the force that acts against the movement of the submarine, slowing it down.
In order for the submarine to stay stable, it has to control a condition called trim. Trim is to balance weight throughout the submarine.
The submarine should be streamlined so that less water resistance acts on it. Thus, the submarine would be able to travel more quickly.
4) Factors that affect floatation and buoyancy
The submarine’s floatation and buoyancy can be affected by factors such as its water pressure, density, shape and size.
- The submarine’s water pressure and depth affects its buoyancy. The bottom of the submarine is at a greater depth than the top of the submarine. Therefore, there is more water pressure at the bottom of the submarine than its top, causing water to push the submarine up. This allows the submarine to float. In addition, water pressure also increases depending on the depth of the submarine in water. The deeper the submarine is, the more water pressure is exerted on the submarine.
- The density of the submarine and the liquid it is in also determines its buoyancy. When the submarine is less dense than the liquid, it will float. If it is...