Have you ever been on a submarine (even just for a tour)?
Yes.
No.
Not Sure.

	What makes nuclear submarines nuclear?
They only carry close family members.
They are nuclear subs only when they carry nuclear weapons.
They use nuclear power to propel the submarine.

	How does a submarine dive underwater?
Everyone on it wears a weight belt, causing it to become so heavy it goes underwater.
The sub takes water into and pushes air out of ballast tanks.
Its powerful back flippers propel a submarine underwater.

	How long can nuclear submarines stay underwater?
Up to several months.
Up to a year.
Until the crewmembers get sick of each other.