What is submarine?

A submarine is like a special kind of boat that can swim underwater just like fish.

Imagine you have a toy boat that floats on water, that’s like a regular ship. But if you put it in a big bucket and fill the bucket with water, the boat will sink. A submarine is like that toy boat, but much bigger and smarter. It has special parts called ballast tanks, which are like air pockets inside the boat. When the submarine wants to go underwater, it lets water into those pockets, making it heavier, just like when you fill your backpack with books instead of toys.

A submarine can move up and down in the ocean by changing how much water is in its ballast tanks. It also has propellers, which spin around like the wheels on a toy car, helping it swim through the water, forward, backward, or even sideways!

Sometimes, submarines hide underwater for a long time, just like how you can hide under a blanket and not be seen. They’re used by people who want to explore the ocean or surprise other boats without being noticed.