Coral Reef

THE CELLS A body immersed in a fluid receiving a push from the bottom, up equal to the weight of the volume of fluid that moves.

The GAV is a practical application of Archimedes' Principle. Positive attitude The specific weight of a body is less than that of water (body floating).

Trim neutral The specific weight of a body is like water (hydrostatic balanced). Negative attitude The specific weight of a body is higher than that of water (body sinks).

PRINCIPLE OF PASCAL Pressure Equipressione internal = external pressure Minor depression internal pressure of external pressure Excess internal pressure greater than the external pressure The law for basic physics of diving, even before those that describe the behavior of gases at different pressures, is that of not compress
of liquids.

The human body consists of a very high percentage of liquid, which explains why, even at depths (and pressures) high, not being "crushed" by the weight of the water.

PRINCIPLE OF TORRICELLI 1 ATM = 1Kg/cm = 760 mm Hg = 1 BAR = 10 meters HO (at sea). A column of mercury to 760 mm in height and 1 cm base weighs 1 Kg (1Kg per cm pressure). In the water pressure increases by 1 atmosphere every 10 meters deep.

Atmospheric pressure Torricelli in 1644 of mercury filled a glass tube long and 1 meter section of 1cm and capovolse in a tank, also filled with mercury. The level of mercury in the tube began to fall, but stopped when it reached the height of 760mm. Torricelli derived that the weight that it wanted the pan (the pressure) was equivalent to that of the column of mercury remained in the tube.

He then described the atmosphere as weight weight of the column of mercury 760 mm high and 1 cm section: why this value is called the "atmosphere" (atm).

Hydrostatic pressure The hydrostatic pressure is a measure of weight (pressure) of a column of water.

Around 1650, Pascal hydrostatic pressure measured by repeating the experiment of Torricelli with a column filled and higher water instead of mercury: the water being lighter mercury (13.6 times) equilibrium was established when the level of water reached the height of about 10m (760 x 13.6).

Unlike air, water, as a liquid, is incomprimibile, so you can observe a constant increase of 1 atmosphere for every increase of 10 meters of water column.
The GAS IN DIVING: COMPOSITION OF THE DRY Components Percentage of total mmHg nitrogen
Argon oxygen, carbon anedrid
Gas rare (Neon, Helium, Krypton, Hydrogen, Xenon, Radon, carbon monoxide do) 78,0840,93420,9460,0330,003 593,47,1159,20250,02.