Physical Effects of Water For Divers
The physical effects of water or the underwater environment are:
- Pressure - the overall pressure on a diver is the sum of the atmospheric pressure and the water pressure.
- Density - of the water, the diver's body and equipment determines the diver's buoyancy and the use of buoyant equipment.
Divers use high density materials such as lead for diving weighting systems and low density materials such as air in buoyancy compensators and lifting bags.
- Thermal conductivity of water is higher than that of air.
As water conducts heat 20 times more than air, divers in cold water must insulate their bodies with diving suits to avoid hypothermia. Gases used in diving have very different thermal conductivity; trimix conducts heat more than air and argon conducts less heat than air hence the reason many trimix divers inflate their drysuits with argon.
- Absorption of light and loss of colour underwater.
The red end of the spectrum of light is absorbed even in shallow water. Divers use artificial light underwater to reveal these absorbed colours. In deeper water no light from the surface penetrates.
- Under pressure, gases are compressible but liquids are not.
Air spaces in the diver's body and gas held in flexible equipment shrink as the diver descends and expand as the diver ascends.
- The absolute (dynamic) viscosity of water is higher (order of 100 times) than that of air. This increases the drag on an object moving through water, and it requires more effort for propulsion in water relative to the speed of movement.
Read more about this topic: Diving Physics
Famous quotes containing the words physical, effects, water and/or divers:
“I became the Incredible Shrinking Mother the year they started junior high. If our relationship today depended on physical clout, I would have about the same influence with them that the republic of Liechtenstein has on world politics.”
—Mary Kay Blakely (20th century)
“Corporate America will likely be motivated to support child care when it can be shown to have positive effects on that which management is concerned about—recruitment, retention and productivity. Indeed, employers relate to child care as a way to provide growth fostering environments for young managers.”
—Dana E. Friedman (20th century)
“The land may vary more;
But wherever the truth may be—
The water comes ashore,
And the people look at the sea.”
—Robert Frost (1874–1963)
“Time travels in divers paces with divers persons.”
—William Shakespeare (1564–1616)