metergolgy ( chapter 4 > required skills and knowledge )

Density is inversely proportional or proportional to pressure ?

Proportional

As pressure increases, the density

increases

Density is inversely proportional or proportional to temperature

Inversely proportional

As temperature increases density

Decreases

As height increases density

Decreases

When does density decrease rapidly

At lower levels

When does density decrease slowly

Higher levels

Varaiations of air density at altitude are

1. 40,000 ft ~ 0.302 kg/m cubed ~ approximately 25% of mean sea level

2. 22,000ft ~ 0.609 kg/m cubed ~ approximately 50% of mean sea level

3. Mean sea level ~ 1.225 kg/m cubed

Which is more dense moist air or dry air

Dry air

Why is moist air less dense than dry air

Because water vapour has a lower mass than oxygen and nitrogen. In humid air water vapour displaces heavier oxygen and nitrogen

Density altitude formula

Density altitude = pressure altitude + ( 118.8 x ISA Deviation )