Diving Manual Chapter 2

Question 1

define: gauge pressure

Answer 1

difference between atmospheric pressure and pressure being measured

Question 2

define: absolute pressure

Answer 2

total pressure being exerted (i.e. gauge pressure plus atmospheric pressure)

Question 3

define: atmospheric pressure

Answer 3

standard atmosphere, usually expressed as 14.7 psi or 1 ata

Question 4

define: Archimedes principle

Answer 4

any object wholly or partly immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object

Question 5

define: boyles law

Answer 5

at constant temperature, the absolute pressure
and the volume of gas are inversely proportional

increase in pressure = decrease in volume

P1V1 = P2V2

Question 6

what is the applicability of boyles law to divers?

Answer 6

relates to changes in the volume of a gas caused by the change in pressure, due to depth, which defines the relationship of pressure and volume in breathing gas supplies

Question 7

what is the conversion between Pata and fsw?

Answer 7

Pata = (depth fsw + 33 fsw) / 33 fsw

Question 8

define: charles’s law

Answer 8

at a constant pressure, the volume of a gas is directly proportional to the change in the absolute temperature

if the pressure is kept constant and the absolute temperature is doubled, the volume will double. If the temperature decreases, volume decreases

V1/T1 = V2/T2

Question 9

what is the equation for the general gas law?

Answer 9

P1V1 / T1 = P2V2 / T2

Question 10

define: dalton’s law of partial pressures

Answer 10

The total pressure exerted by a mixture of gases is equal to the sum of the pressures of each of the different gases making up the mixture, with each gas acting as if it alone was present and occupied the total
volume

Question 11

define: partial pressure

Answer 11

the portion of the total pressure contributed by a single gas

Question 12

what is the equation for SEV?

Answer 12

SEV = pp / 1 ata

Question 13

define: henry’s law

Answer 13

The amount of any given gas that will dissolve in a liquid at a given temperature is directly proportional to the partial pressure of that gas

Question 14

what is the applicability of henry’s law to diving?

Answer 14

as one dives deeper and deeper, more gas will dissolve in the body tissues and that upon ascent, the dissolved gas must be released

Question 15

define: gay-lussac’s law

Answer 15

the pressure of a given mass of gas varies directly with the absolute temperature of the gas, when the volume is kept constant

P1/T1 = P2/T2