Glossary
Backscatter
Light scattered back towards a camera or observer by particles in the water.
Read resource →THE DIVER’S RESOURCE CENTRE
Better questions. Useful answers.
Find a lesson, look up a word, check the forecast or find the manual for your gear. Bring your next diving question here.
FIND YOUR NEXT ANSWERNEW / INTERACTIVE TOOLS
Planners, checklists & logs
Eight tools to organise a trip, compare courses, keep equipment records and prepare useful notes.
Open the tools →01 / BEFORE YOU TRAVELWeather & dive preparation
Official forecasts, tide information and a worksheet to take to your briefing.
Open the preparation resources →02 / KNOW YOUR EQUIPMENTManuals & manufacturer support
Find the correct documents for your model and prepare a useful support enquiry.
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Search published guides, beginner lessons, safety topics, courses, brands and glossary definitions. Planned articles are excluded.
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Glossary
Bar
A unit of pressure equal to 100,000 pascals.
Read resource →Glossary
BCD
Buoyancy control device: equipment with an inflatable chamber used as part of a diver’s buoyancy system.
Read resource →Glossary
Boat dive
A dive accessed from a vessel.
Read resource →Guides
Boat Diving in Australia: A Practical Guide
Entries, exits, seasickness, briefings and equipment routines for day boats, RIBs and liveaboards around Australia.
Read resource →Glossary
Boat traffic
Vessel movement in an area that needs consideration in local planning and briefings.
Read resource →Safety guides
Boats, ladders and propellers
Surface activity around a boat needs the same attention as the underwater portion of the dive.
Read resource →Glossary
Boyle’s law
For a fixed amount of gas at constant temperature, pressure and volume vary inversely.
Read resource →Glossary
Breathing gas
Gas intended for breathing during the activity; its composition and suitability must be established.
Read resource →Beginner lessons
Breathing gases are not interchangeable
Recognise why a gas name implies training and limits.
Read resource →Glossary
Briefing
A discussion that explains the intended activity, arrangements and relevant conditions.
Read resource →Glossary
Buddy
A diving partner participating in an agreed system of communication and mutual awareness.
Read resource →Interactive tools
Buddy briefing worksheet
Record shared goals, equipment questions, communication and unresolved points before the local briefing.
Read resource →Safety guides
Buddy separation and missing divers
Separation procedures must be agreed before the dive, when everyone can communicate clearly.
Read resource →Guides
Build a scuba-course study plan that leaves time for questions
Organise course preparation, terminology, questions and review around the training provider’s actual requirements, without rushing practical learning.
Read resource →Safety guides
Build a shared dive plan
A plan is useful only when both divers can explain it in their own words.
Read resource →Guides
Build a weather backup plan for your diving holiday
Prepare useful alternatives, booking questions and a decision contact so a changed dive itinerary does not unravel the whole holiday.
Read resource →Glossary
Buoyancy
The upward force exerted by a fluid on an immersed object.
Read resource →Safety guides
Buoyancy and weighting
Stable buoyancy helps protect the diver, the buddy and the environment.
Read resource →Beginner lessons
Buoyancy as a force
Describe positive, negative and neutral buoyancy.
Read resource →Guides
Buying used scuba equipment: build an evidence file first
Organise model details, history, manufacturer information and professional assessment before deciding whether used scuba equipment makes sense.
Read resource →Safety guides
Calling the dive without pressure
Every diver needs a clear, respected way to decline or end a dive.
Read resource →Safety guides
Carbon dioxide retention
Breathing difficulty and excessive workload underwater deserve an early response.
Read resource →Courses
Cave Diver
Full overhead penetration diving, where direct ascent is not available at any point.
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