The science of submarines

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772px-Papa_class_submarine_2Boats are cool, submarines are even cooler! But just how do they manage to move around submerged so effortlessly? Dutchman, Cornelius Drebbel, had the answer and decided to share it with the world all the way back in 1620, when he built the very first submarine. If you’ve ever been on a boat, you’ll know that the journey can get pretty rough from time to time. This is because the sea is most choppy at the surface, where the wind and water meet each other.

Wind is developed from energy that comes from the sun and spends its time bouncing back from one side of the planet to the other. If you’re on a boat in times of high wind, then you’ll likely bump into some big waves. Submarines don’t  have this problem because submarines can glide easily under the waves.


Submarines are complex machines with many components and below are three of the most important:


Just like a boat or even a car, submarines need an engine to move from one place to another. Most submarines have engines which operate off both diesel and electricity, where the electric engine runs from a generator to power the propellers of the submarine. The diesel engine is used to recharge the generator and keep a constant flow of power to the electric engine. Nuclear submarines are the exception as they use nuclear propulsion for power.


Ballast Tanks

These are compartments at the sides of the submarine which help it to submerge or rise to the surface… Submerging is done by filling these compartments with sea water, which is then released and replaced by air if the submarine needs to rise to the surface.


Hydro Planes

Just like sharks need fins to navigate through the water, submarines need fins known as hydro planes to control their position underwater. As the submarine propels forward and water rushes over the hydro planes, their position can be changed to create an upward or downward force that adjusts the angle at which the submarine is moving.
Above is a short video that helps explain further how submarines work. 😉


Inquiry – Digging Deeper


Now that we know about some of the key parts of a submarine, why not make your own submarine. Here’s what you’ll need:

  • 3 straws
  • Plasticine
  • A bowl of water
  • Scissors
  • A bottle of water


Take a look at the instructional video below for a step-by-step guide on how to build it. You will also be able demonstrate how air pressure influences the way the submarine floats!