Why Does a Submarine Go Up and Down?

What Crafty Clover says in this video

Intro

Hey there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why does a submarine go up and down?

The Big Idea

A submarine has special tanks called ballast tanks. Filling them with seawater makes the sub heavier than the water it pushes aside, so it sinks. Blowing the water out with air makes it lighter, so it rises!

Tanks Fill with Water

Step one: the tanks fill with water. Valves open, and seawater flows into the ballast tanks. The submarine gets heavier.

It Slides Under

Step two: it slides under. When the sub is heavier than the water it pushes aside, it sinks. Fins called diving planes help steer it down while it moves.

Air Pushes the Water Out

Step three: air pushes the water out. To rise, the crew blows air into the tanks. The air pushes the water out, so the boat gets lighter and climbs back up!

A Closer Look

Let's take a closer look inside a submarine! The ballast tank holds water or air. The hull is the strong outer shell. And the diving plane is a fin that steers the sub up or down. Up and down is a buoyancy switch the crew controls!

Quick Facts

Quick facts! A submarine follows the same buoyancy rule as a ship, but it can change its weight on purpose. Fins called diving planes help steer a sub up or down while it moves. Crush depth is real, and every submarine has a limit. Submarines are for trained crews only. Visit a museum or watch a film instead.

Think Like a Scientist

Now, think like a scientist! Let's think about floating. Why does a submarine change its weight instead of flapping wings? What two things can the tank switch between? With a grown-up, fill a bottle partly with water in a tub. Does it float or sink? Remember, keep water play safe, with a grown-up nearby.

Outro

Up and down is a buoyancy switch the crew controls. Science is amazing! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!