q Air molecules in
the parcel (or the balloon) have to use their kinetic energy to expand the parcel/balloon.
qTherefore, the molecules
lost energy and slow down their motions
q è The temperature
of the air parcel (or balloon) decreases with elevation. The lost energy is used to increase the
potential energy of air
molecular.
qSimilarly when the air
parcel descends, the potential energy of air molecular is converted back to kinetic energy.
q è Air temperature rises.