How Do Submarines Dive and Surface?

Modern submarines can dive up to 240 meters below the surface of the water. When the crew is ready to submerge, external ballast tanks that are normally filled with air, open to receive water. This makes the ship slightly negatively buoyant.

#ImpossibleEngineering
Wednesdays 9/8 on Science
http://www.sciencechannel.com/tv-shows/impossible-engineering/

Subscribe to Science Channel:
http://bit.ly/SubscribeScience

Check out SCI2 for infinitely awesome science videos. Every day. http://bit.ly/SCI2YT

Download the TestTube app:
http://testu.be/1ndmmMq