Open Water Scuba Diver

Terms that help describe the behavior of light in water include refraction, absorption, reflection, and diffusion. Light is radiant energy and, as the rays travel from the sun into water, these rays are refracted or bent as they travel into the denser medium. Refraction occurs because the density of the water causes the speed of […]

Because water is denser than air, both light and sound behave differently than in air. Light being radiant energy, slows down, while sound being physical vibration, speeds up. Sound travels about 4.5 times faster in water than in air, therefore it is almost impossible to tell which direction from which the sound is coming, therefore

When cylinders are filled, there is an exothermic reaction. The action of the air being compressed creates heat. When the air in the tank cools, the pressure goes down. The change is approximately 5 psi per degree Fahrenheit (17 psi per degree Celsius.) The more slowly the cylinder is filled, the less it heats up.

When you work in a contaminated air environment, the substances you take into your lungs may be harmful to you. If that same contaminated air were to be breathed at depth, the effect of breathing the contaminated air can increase equal to the depth in atmospheres. Nasty air at the surface taken to depth could

Your breathing pattern at depth is different than up in air. Part of our challenge is to eliminate the carbon dioxide (CO2) that is created during our body’s metabolic processes. Therefore, with more pressure of oxygen available at four atmospheres in depth, we still must breathe at the same rate and volume as at the

William Henry, in 1803 formulated Henry’s Law that states: “At a constant temperature, the amount of a given gas that dissolves in a given volume of liquid is directly proportional to the partial pressure of that gas.” This helps us explain that at depth, the nitrogen portion of the air we are breathing dissolves in

Another consideration is the amount of air we use with every breath. We don’t think much about that above the water’s surface because there is plenty of it. However, below the surface on scuba, we are limited by the amount of air in our cylinder. This becomes a bit more complicated when we consider that

Because the gas bubbles in the wetsuit become compressed at depth, we add air to the BC to remain neutral. In addition, here is a list of those items that affect our buoyancy. Note that two of those change often throughout the dive. As we begin the ascent to the surface, the opposite effect occurs.