Incredible submarines

Have you ever seen a submarine? They are boats that can dive deep underwater and stay there for an extended period of time-sometimes as long as six months. Readers of this engaging text will learn just how this is possible. They will discover the different parts of a submarine, from the periscope at the top-used to look out at the surroundings above the water-to the engine room, which powers propellers that allow the submarine to glide through water. Color photographs show different submarines in all their glory.