Physics of freediving

During freediving courses, you experience physicals conditions that affects your body. You will learn to appreciate the surrounding pressure and how to avoid risks

Feel The Pressure

You won’t have to dive too deep to feel the pressure but the deeper you go, the better your will feel the pressure. At 10m deep, the pressure is 1 bar ata, it means that your feel twice as much pressure than when you’re out of the water. Every 10m deep, you add 1 bar, as at 30m deep you would feel 4 atmospheres.

Why do we care about pressure?
Pressure doesn’t affect liquid but it can compress gas, that is one of the reason why we « feel »pressure. The gas volume reduces of one half at 10meters deep. As the gas volume reduces inversely and proportionally to the pressure, it means that it will be one third of is size at 20m.

The body is almost fully composed of water, as it doesnt compress, you will feel the pressure where you have air spaces in your body (ears, lungs, mask, wet suit…). During the freediving course, you will learn how to keep these air space in balance with the surrounded pressure, and manage to dive deeper without feeling pain because of the pressure.

About your senses

First of all, depth affects your sight. The first way it does it is because of the water reflexion that bend light rays, that phenomenon is even stronger when you go deeper. The second reason why your sight is affected is because depth absorb the light rays, as your perception of colours is very different, as it disappears. Very relaxing for your brain even if he still makes the difference because a compensation response.

The second effect on your senses is about earing. You have already noticed that sound is different underwater. Depth is a very quiet world; you may even hear your own heartbeat.
In the water, the sound travels faster than in air. It makes things sound much more closer than they are. As the sound reaches your both ears at same time, you can’t determine where does the sound come from. As when you hear a sound, it sounds like being all around you!

About feeling of temperature

In the water, heat is absorbed faster than in air. So you have to control your body temperature wearing a wet suit to stay comfortable during an extended period. During your freediving course, you will also learn to choose the right wet suit, the one that could make you stay in the water longer. You may also decide not to use a wetsuit as the water temperature in Thailand is very warm.

About orientation

Buoyancy reduces your perception of gravity, that is why you may be disoriented. Where is up? Where is Down? You will learn how to maintain you orientation visually.

SSI Freediving Level 1 course is composed of several steps.

Theory section where you would be able to learn the principles of freediving.

You will mainly learn about the freediving physics. It's very interesting to discover how depth can affect all your senses and how you body react to freedive immersion

Pool Sessions where you would be able to learn breathing techniques for which you would put into practice: Static Apnea and dynamic apnea.

Open water sessions with an objective of constant weight apnea of 20 meters.

You will use :

• Freediving Mask
• Fins
• Wetsuit (but not mandatory)
• Weight belt
• Surface Signaling Device

It's very important to learn how to use the freediving gear correctly. Wear the correct wetsuit, fins, know how to quickly defog your mask could makes the difference. Moreover it is important to know how to use the gear for safety. Indeed you must not wear a overweighted belt for exemple.

• To be at least 12 years of age
• Be able to float at the surface