How does a submarine work ?

What is submarine & why do we need it ? Imagine you are on-board a ship & what would be the worst thing that would happen to you ? – the water flooding inside the ship making it sink to the seabed…damn…! So we need something which ensures either it doesn’t sink OR even…

SURPRISE ME !

How do ships float ?

Thinking or wanna walk on water ? – really bad idea. Why cant we walk on water ? Why does not everything float ? Why doesn’t a stone or any other thing float even if they are are very small ? & HOW DO SHIPS FLOAT BEING SO HEAVY ? I bet…

SURPRISE ME !