Some text appears on screen asking a question about a topic in SCUBA diving safety.  The scene changes to show a lot of SCUBA air tanks and some more text explaining more about the question.  A man is SCUBA diving underwater while holding his air tank in his hands and the text continues to explain.  The air tank is seen floating on it's own on the sea bed.  Another man is SCUBA diving and he lets go of his tank to demonstrate the buoyancy.  The scene switches back to the group of air tanks with more text explaining.  Another scene is shown with 2 tanks and a bag next to some trees.