Submarine

                 Let us begin first what a submarine is? A submarine is a special kind of boat that is able to go underwater. While most other boats are made to float, a submarine is made to do both: Travel on top of the water or beneath it. Now that’s interesting!  Submarines are incredible pieces of technology. Not so long ago, naval forces worked entirely above the water. But with arrival of submarines we can use the underwater sea as well. Jules Verne in his science fiction, 20,000 Leagues under the Sea, mentions a ship, Nautilus, which could dive beneath the waves and surface again when it wanted to. Even before submarines were thought about, Verne had created the blueprint of this technological marvel. Not only did he describe the machine, but he also explained, in great detail, how it worked. In fact, today's submarines use exactly the same technology as Verne's Nautilus did!

Designs for underwater boats submarines date back to the 1500s and ideas for underwater travel date back even further. However it was not until the 19th century that the first useful submarines began to appear. During the Civil War, the Confederates built the H.L. Hunley,the submarine that sank a Union ship. The U.S.S. Housatonic was built in 1864. But it wasn't until after World War I began that the first truly practical and modern submarines were invented

Now to understand the working of submarine first consider a small experiment which you might have tried even. Take an empty mug and turn it upside down. Now try and push the mug inside a bucket full of water. You will have to apply a lot of pressure to do so. But once you release the pressure, the mug simply floats back to the top. What this experiment concludes is thatair is lighter than water. The mug resurfaces because the air trapped inside it makes the mug lighter than water. This makes the mug float.

                A submarine or a ship can float because the weight of water that it displaces is equal to the­ weight of the ship. This displacement of water creates an upward force called the buoyancy force and acts opposite to gravity, which would pull the ship down. Unlike a ship, a submarine can control its buoyancy, thus allowing it to sink and surface at will. Also submarines are closed making it useful for underwater navigation. Now to get a feel of it you might have noticed that while bathing in a swimming pool or lake the body feels lighter in weight, this is precisely due to upwards buoyant force.

To control its buoyancy, the submarine has ballast tanks and auxiliary, or trims tanks, that can be alternately filled with water or air. When the submarine is on the surface, the ballast tanks are filled with air and the submarine's overall density is less than that of the surrounding water. We know that an object can float in water until its density is less than that of water like we did in that little experiment.  As the submarine dives, the ballast tanks are flooded with water and the air in the ballast tanks is vented from the submarine until its overall density is greater than the surrounding water and the submarine begins to sink. A supply of compressed air is maintained aboard the submarine in air flasks for life support and for use with the ballast tanks. To keep the submarine level at any set depth, the submarine maintains a balance of air and water in the trim tanks so that its overall density is equal to the surrounding water.

Now let us design a small submarine for ourselves

• Step 1 - Slip a small, round balloon into a small, empty plastic bottle. A bottle holding about a pint should work well. Blow up the balloon as much as you can while the body is inside the bottle, and tie off the end.
• Step 2 - Fill the small bottle with water as much as you can. You may colour the water if you like to personalize your submarine. Screw the cap onto the bottle tightly.
• Step 3 - Pour the clear pitcher full of water. Slip the bottle into the water and watch what it does. It should sink to the bottom, then float gently back up until it eventually settles near the middle of the pitcher.

As we can see that our small little bottle submarine remains suspended in water though we cannot vary its depth as we have not made a mechanism to vary the amount of water and air.

Naturally, as has been discussed, submarines have played a major role in our country’s navy. They make up over 2% of naval vessels. Submarines are effective in our military because they allow a stealth way to enter into enemy waters and possible attack.

Submarines are most prominent in navies; however, they are also used in other venues. In recent decades, they have become much more commonly used as a research tool as well. They allow scientists to travel deep into the see and study deep water sea life. Not long ago, the depths of the oceans were a mystery; no one had been deep enough to see what really existed beneath the surface. With submarines, however, researchers are allowed a safe way to study the deep sea, without having to die doing so. What a concept.

Submarines have also become more popular in tourism. Mostly in warm climates, these vessels will take tourists close to the ocean floor, in a dry, safe medium. These submarines use the same concepts as those used in the navy, however, they are produced on a much smaller scale, without some of the cool gadgets, like torpedoes.

Submarines are great tools that can be used for various different things. They are used by the navy, researchers and tourism companies to explore, and navigate areas that are not accessible with a scuba tank and a wet suit. Although I have never actually been on a submarine, I can still say without a doubt, they are cool!

     -MAYAND DAVE