Introduction Flashcards
Define Conduction
The transfer of thermal energy from two objects at the point they are in contact.
Define Convection
The distribution of heat through a fluid. The hotter fluid becomes less dense and rises, as it cools it becomes more dense and falls, creating a circular motion.
Define radiation
The transfer of energy via radiated heat. It is electromagnetic radiation. Two objects transferring heat without being in contact.
Good example - the heat from the sun coming to earth.
Define advection
The horizontal flow of air.
Define Latent Heat
Instead of a fluid changing temperature as heat is added, it can change phase. For example - as water boils it will increase temperature to the point where the phase is changed to a gas. Continuing to boil it will no longer make it hotter, but will instead trigger a phase change.
Define specific heat
The amount of energy required to be added or removed to change a material’s temperature by 1 degree C.
Define Height
The vertical distance above a certain datum - e.g. Ground level. (AGL)
Define Altitude
The vertical distance above Mean Sea Level
Define Elevation
The vertical distance above Mean Sea Level of some point on the ground.
Define QNH
The measure of air pressure at mean sea level for a given point on earth.
Setting the QNH on the sub scale of an altimeter will give the current altitude above Mean Sea Level
Define QFE
If we adjust the pressure sub scale on the altimeter so it reads 0ft, we have set QFE. It is a measure of the ambient air pressure at the current elevation.
Define Pressure Height
Setting the QNH to 1013 on the Altimeter will give you pressure height. It is the height above Mean Sea Level in the International Standard Atmosphere
What is the formula to calculate Pressure Height?
Pressure Height = (1013 - QNH) x 30 + Elevation.
With an Elevation of 2300ft and a QNH of 1023, what will the Pressure Height be?
2000ft
What is the ISA temperature at Sea Level?
15°C.
