It's called convection. The air is headed next the the warm body and
this sets up a current as the warm moves away and the to be replaced by
cold air which draws away more heat.
However, air is one of the most effective insulators known if it is
contained in many small pockets. This is how down, thinslate, closed
cell foam, fiberglass and styrofoam work. The capture of air in many
small pockets keeps the currents from being established and hence keep
the warm air next to the warm body. An air mattress will remove heat
from the body very rapidly. The best insulation to sleep on is closed
cell foam ( open cell foam air mattresses such as "Thermorest"). I've
sleep in a snow cave on a closed cell foam pad and have been quite
toasty. Both are available at places like REI.
I've always heard that the layer of air in an air mattress just
conducts the cold from the ground right up to you. My husband and I
found this to be true at a Dec. ride several years ago...we were
absolutely miserable in our tent and air mattress (about 5-6" thick
mattress). We luckily had a little propane heater, which we had to
replace the canister on every 3-4 hours or so. We spent 3 nights in
that tent. Up side is, the next weekend my husband said "Let's go
trailer shopping!", and 10 days later we had our LQ trailer! I'd have
dragged him to a cold ride a long time before that if I'd known that
was all it took to get a LQ trailer! <VBG>
Dawn in East Texas
-- We imitate our masters only because we are not yet masters
ourselves,
and only
We
imitate our masters
only because we are not yet masters ourselves, and only
because
in doing so we
learn the truth about what cannot be imitated.
