PADI IDC Revision – Skills and environment

Skills and environment – Currents, Tides and Waves

PADI IDC revision – Skills and environment -Major Ocean Currents/Tides/Waves/Longshore current/Rip current

PADI IDC Revision - Skills and environmentOn PADI Divemaster and Instructor exams, people often get confused with the different subjects of Major Ocean Currents, Tides, Waves, Longshore drift, and Rip Currents.  All of these topics involve the movement of water. Perhaps that is why some people get confused. So with your PADI IDC Revision – Skills and environment, we need to spend a little time just getting used to the words, and attaching the correct answers to each subject.


[break]I hope that this video helps.[break]


How did you get on with your PADI IDC Revision – Skills and environment?

Can you answer these questions?

What causes Major Ocean Currents?

The rotation of the earth.

In general, what is the best time to dive?

In general, it’s best to dive at the high tide or the slack period between high and low tides.

What causes a Longshore current?

Waves approaching the shore at a slight angle and pushes water down the shoreline.

What causes tides? 

The gravitational pull of the Sun and the Moon. The moon having a greater affect. Also topographical features in some circumstances.

What causes waves?


What causes a Rip Current?

Waves pushing water over a long obstruction lie a reef. The water cannot escape, so it funnels back to sea where there is an opening.

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PADI IDC Revision – Skills and environment

There are only a few questions about the coriolis effect, but the ones that do sometimes cause confusion.
It’s best to take a moment to scribble a quick map of the world on scrap paper, draw a clockwise circle in the north and counter clockwise in the south, and then focus on the question.

Here is a video giving much more information than can be found in PADI manuals.

Now let’s look at some questions

Which way do the major currents move in the northern hemisphere?


What causes major ocean currents?

Wind and the earth’s rotation

Which way do major Oceans travel in the Southern hemishphere?


 In which direction would the major ocean current travel on the east coast of a continent in the northern hemisphere?

South to North ( think it through!  in the north, the current is clockwise, so would hit the east coast from the bottom and travel north )

I hope that you enjoyed the PADI IDC Revision – Skills and environment. The questions that you found on this page are very common questions used on most PADI exams.
For more help, sign up for my Distance Learning Preparation course, and I’ll help you to get right up to speed in both PADI dive Theory, and PADI Standards.

There are some more PADI IDC Revision – Skills and environment questions here:

What is the most accurate form of measurement underwater ( without using a measuring device) ?

Arm Spans.  – Arm Spans are the most accurate. Imagine that you wanted to know the width of a wreck. You could be fairly accurate by using Arm Spans.

What equipment is recommend for every diver to carry on a night dive?

One primary light, a back up light and a chemical light.  ( on a PADI night diver speciality, each diver must at least have their own light )

What should you consider when determining a search pattern to use for a lost object?

The size of the object and the bottom topography. In addition, the size of the search area and equipment available.

The generally preferred method for providing rescue breaths to a non-breathing diver at the surface is:

Mouth to pocket mask