Submarines stay underwater for long periods by using ballast tanks that are filled with water to increase weight and dive or filled with air to decrease weight and surface. They are powered by nuclear reactors or diesel-electric engines, allowing them to operate underwater for extended periods without the need for frequent resurfacing.

MCQs

1. What do submarines use to move forward underwater?

A) Paddles
B) Propellers
C) Balloons
D) Legs

 

2. How do submarines change their depth in the water?

A) By flapping wings
B) By changing the air in the tires
C) By adjusting the amount of water in the ballast tanks
D) By waving a magic wand

 

3. What is the primary source of oxygen for submarines when underwater?

A) Plants
B) Oxygen tanks
C) Windows open to catch air
D) Fish

 

4. How do submarines see what’s ahead of them underwater?

A) With a periscope
B) With a telescope
C) With glasses
D) With a flashlight

 

5. What technology allows submarines to map the ocean floor and detect other objects underwater?

A) X-ray vision
B) Radar
C) Sonar
D) GPS

 

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