How does being underwater affect the apparent size or distance of things? - ANSWER
What you see is magnified by a third. This makes things look larger or closer, or both, de-
pending on your perspective
How does water affect light intensity and colour? - ANSWER The deeper you got the
darker it gets.
As you go deeper, red is the first colour absorbed, followed by orange, yellow, green and fi-
nally blue.
How does hearing differ underwater? - ANSWER You hear more efficiently because sound
travel further and four times faster in water than in air. Sounds seem to come from directly
overhead.
How does water's density affect moving in water? - ANSWER It takes more energy the
faster you try to swim
How do I move efficiently as a diver? - ANSWER Slow and steadily
How does streamlining benefit me as a diver? - ANSWER Reduces drag, vin turn reduces
energy
Why is trim important to streamlining, moving efficiently and protecting underwater envi-
ronment? - ANSWER You float with your feet and head relatively level
1
, What skill allows me to use water's density to make moving in water more efficient? - AN-
SWER The correct trim
Why do I chill faster in water than in air at the same temperature? - ANSWER Water ab-
sorbs more heat than air of the same temp, and absorbs it about 20 times faster.
What do I do to stay comfortably warm while diving? - ANSWER Choose an appropriate
exposure suit to insulate you
What should I do if I'm not warm enough while diving? - ANSWER End the dive and use
more exposure protection next time
What should I do if I start shivering uncontrollably? - ANSWER Exit the water immedi-
ately, dry off and seek warmth
What is the most effective way to breathe while diving? Why is it important? - ANSWER
breathe slowly and deeply - important for effective gas exchange
What is 'airway control'? What are two techniques for it? - ANSWER The skill of breathing
past remaining water without drawing any into your throat.
1. Inhale slowly. If you inhale slowly water tends to stay in the mouthpiece while the air gur-
gles past into your mouth and lungs. It helps to look downwards a bit.
2. Touch your tongue to the roof of your mouth as you inhale. Your tongue will tend to block
water as air flows around it. Again, looking down helps. Can combine both methods.
What are eight symptoms of overexertion while diving? - ANSWER fatigue
laboured breathing
a feeling of suffocation or air starvation
2
What you see is magnified by a third. This makes things look larger or closer, or both, de-
pending on your perspective
How does water affect light intensity and colour? - ANSWER The deeper you got the
darker it gets.
As you go deeper, red is the first colour absorbed, followed by orange, yellow, green and fi-
nally blue.
How does hearing differ underwater? - ANSWER You hear more efficiently because sound
travel further and four times faster in water than in air. Sounds seem to come from directly
overhead.
How does water's density affect moving in water? - ANSWER It takes more energy the
faster you try to swim
How do I move efficiently as a diver? - ANSWER Slow and steadily
How does streamlining benefit me as a diver? - ANSWER Reduces drag, vin turn reduces
energy
Why is trim important to streamlining, moving efficiently and protecting underwater envi-
ronment? - ANSWER You float with your feet and head relatively level
1
, What skill allows me to use water's density to make moving in water more efficient? - AN-
SWER The correct trim
Why do I chill faster in water than in air at the same temperature? - ANSWER Water ab-
sorbs more heat than air of the same temp, and absorbs it about 20 times faster.
What do I do to stay comfortably warm while diving? - ANSWER Choose an appropriate
exposure suit to insulate you
What should I do if I'm not warm enough while diving? - ANSWER End the dive and use
more exposure protection next time
What should I do if I start shivering uncontrollably? - ANSWER Exit the water immedi-
ately, dry off and seek warmth
What is the most effective way to breathe while diving? Why is it important? - ANSWER
breathe slowly and deeply - important for effective gas exchange
What is 'airway control'? What are two techniques for it? - ANSWER The skill of breathing
past remaining water without drawing any into your throat.
1. Inhale slowly. If you inhale slowly water tends to stay in the mouthpiece while the air gur-
gles past into your mouth and lungs. It helps to look downwards a bit.
2. Touch your tongue to the roof of your mouth as you inhale. Your tongue will tend to block
water as air flows around it. Again, looking down helps. Can combine both methods.
What are eight symptoms of overexertion while diving? - ANSWER fatigue
laboured breathing
a feeling of suffocation or air starvation
2
