Section 1

Question 1

How does pressure change as you go down?

Answer 1

1 bar per every 10 meters

Question 2

Changes in pressure, air volume and density

Answer 2

Meters - Air volume - air density

10 1/2 x2
20 1/3 x3
30 1/4 x4
40 1/5 x5

Question 3

Equalisation

Answer 3

Adding air to air spaces as you descend

Question 4

When to equalise?

Answer 4

Every meter, before you feel discomfort

Question 5

What to do when you cannot equalise

Answer 5

Signal and stop
Ascend slightly, try again
Stop if not working

Question 6

Most important rule

Answer 6

Always breath, never hold your breath

Question 7

What to do when you don’t have your regulator in your mouth?

Answer 7

Breath out slowly

Question 8

Reverse squeeze

Answer 8

When expanding air gets trapped in a body air space during ascend

Question 9

How long does your air last?

Answer 9

Follows the pressure/ volume relationship

Half as long at 10 meters under than on the top

1/3 as long as 20 meters compared to the top

Question 10

Energy and breathing

Answer 10

More pressure = denser air = harder to breath = use more energy

Question 11

Why does salt water cause more buoyancy?

Answer 11

Because it weighs more because of minerals in it

Question 12

BCD

Answer 12

Buoyancy control device

Question 13

Positive buoyancy

Answer 13

Floating

Object weights less than the water it displaces

Question 14

Short cut buoyancy and air

Answer 14

More air = you expand = more volume = more buoyancy = up

BCD - reverse
Because when you ascend the gas you already have expands with less pressure, to you release / vent on your BCD to control your buoyancy

For descend, as pressure increases, your volume also decreases, reduces the water displaced, less buoyancy. Add air to your BCD to offset

Question 15

Primary gear consideration

Answer 15

Suitability, fit, comfort

Question 16

Why does your mask need to encompass your nose?

Answer 16

You need to blow air into your mask to equalise the pressure

Question 17

Good mask

Answer 17

Sits close to your face for better vision

Question 18

BCD Components

Answer 18

Inflatable bladder
Cylinder band & harness/jacket 
Lower pressure inflator (lpi)
Over pressure exhaust valve
Weight system

Options:
Buoyancy / lift 
Pockets 
D-rings 
Quick release / colours etc

Question 19

Regular components

Answer 19

First stage/hub - connects supply to other competent s
Second stage - reduces first stage intermediate pressure to air you can breath. Deliver air only when you inhale + purge buttons to release air
Alternate air source / octopus - air for your buddy
Low pressure inflator (lpi) - supplies air into your hose
Submersible pressure gauge (spg) - indicates pressure remaining in your tank

Question 20

Two aspects of weight system

Answer 20

1. Right amount

2. Trim: horizontal position for floating

Question 21

Vision and earring under water

Answer 21

Magnifies by a third, as water is more dense than air
You may see colour loss as you go down: red, yellow, green, blue

Sounds travels 4x faster