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