Do you happen to remember this statement;
“An object wholly or partially immersed in liquid is buoyed up by a force equal to the weight of the fluid displaced by the object”
That is Archimedes Principle; it is also one of the more important principles in diving. As scuba divers here in the Northwest Indiana and Chicago area, we contend with Archimedes more than those in the South Pacific or Caribbean. Why, because we are wearing exposure suits. So unless your instructor didn’t like you, and had you dive in just shorts and t-shirt, you were most likely wearing some sort of exposure suit. That being a wetsuit or even a dry suit.
When I work with new divers, they ask why is it we need “X” amount of lead? Then we suit up in a wetsuit, take a walk down to the deep dock and jump in feet first. With shock, they bounce back to the surface, sometimes about mid chest out of the water. They are learning the first functions of Archimedes Principle. Because of the construction of the wetsuit, they might be gaining another 15 to 20 pounds or more of “positive” buoyancy.
We also take this moment to talk about positive and negative buoyancy. Hey, our scuba lessons are built around you being able to apply what we are talking about. So as we establish what is “positive buoyancy”, that being able to float on the surface with no effort, the other two phases of Archimedes Principle is “negative buoyancy” and “neutral buoyancy”.
Your successful diving in the Midwest environment deals more us being able to achieve the phase of Neutral Buoyancy. How we do that and maximizing your comfort will be talked about more in the next segment of this blog.