Janet Kaiser on fri 2 nov 01
One of those 1001 Useless Facts I hoard...
Inuit people (also known as Eskimos) across the Arctic,
use unconnected freezers and refrigerators to keep food
warm and prevent it from freezing. They are so well
insulated, especially the most efficient ones. Maybe
your local rubbish dump or recycling centre would be a
good source? Just get them to take out the nasty ozone
depleting refrigerants first. Not much need of the
motor either, so take it out so it is lighter to carry
and move around.
As heating anything from cold to warm takes the most
energy, it is not wasteful leaving a studio heated
overnight. On the contrary, it will save you energy.
How about using one of those greenhouse (aka a
glass-house) heaters? And improving the insulation?
Double glaze the windows, even if it is just polythene
pinned to the frame for the winter.
As water takes a lot of energy to heat, keep your
studio as dry as possible. Install a dehumidifier if
the atmosphere is damp and air it well once a day.
Warm water may be a wimps way, but it is kinder to your
skin and joints.
Apart from those little pearls of wisdom, I have been
thinking...
If hot air does not rise, how come hot air balloons are
the most efficient at going upwards?
If hot air does not rise, how come my unheated,
upstairs office in The CoA is 10 degrees warmer than
the room below?
If hot air does not rise, why do we build chimneys
upwards and not have a simple hole in the wall?
If hot air does not rise, how come when we were
painting the ceiling in The CoA the paint was drying on
the brush, whilst 20 feet below it took all day to dry
on the wall?
If hot air does not rise, why do we lag and insulate
roof spaces and lofts?
If hot air does not rise, how come animals used to be
kept downstairs and farmers slept above to keep warm?
Hummmmm?
Janet Kaiser
The Chapel of Art . Capel Celfyddyd
HOME OF THE INTERNATIONAL POTTERS' PATH
Criccieth LL52 0EA, GB-Wales Tel: (01766) 523570
E-mail: postbox@the-coa.org.uk
WEBSITE: http://www.the-coa.org.uk
John Baymore on sat 3 nov 01
Apart from those little pearls of wisdom, I have been
thinking...
If hot air does not rise, how come hot air balloons are
the most efficient at going upwards?
If hot air does not rise, how come my unheated,
upstairs office in The CoA is 10 degrees warmer than
the room below?
If hot air does not rise, why do we build chimneys
upwards and not have a simple hole in the wall?
If hot air does not rise, how come when we were
painting the ceiling in The CoA the paint was drying on
the brush, whilst 20 feet below it took all day to dry
on the wall?
If hot air does not rise, why do we lag and insulate
roof spaces and lofts?
If hot air does not rise, how come animals used to be
kept downstairs and farmers slept above to keep warm?
Janet,
Darn you...... I said I wasn't going to post anything else on this.
It isn't that hot air balloons go upward.... it is that the ground moves
away from them. (Kidding....kidding!)
Your understanding is CORRECT..... hotter air DOES rise! It is less
dense.....boyant in colder air....weighs less per unit of volume. It
"floats". Or as has been pointed out..... the dense cold air holds it up=
.
This verbal gobbeldygook of mine has been revolving around the distinctio=
n
between "hot air" and "heat energy". =
Best,
..............................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752 (s)
800-900-1110 (s)
JohnBaymore.com
JBaymore@compuserve.com
John.Baymore@GSD-CO.com
"Earth, Water, and Fire Noborigama Woodfiring Workshop 2002 Dates TBA"=
Snail Scott on sat 3 nov 01
At 07:10 PM 11/2/01 -0000, you wrote:
>If hot air does not rise, how come hot air balloons are
>the most efficient at going upwards?
Actually, I believe the argument is that hot air does
rise, becaude it can move and be displaced by cooler
air. The movement of hot air upward is called convection.
Heat in an object moves by conduction, not convection,
and since no displacement is occurring (either in the
upward or downward direction,) the heat moves evenly
through the object in all directions.
(It might get a bit hotter in the upward direction
because the hot object is heating the air around it by
radiation, and the hot air will move upward around the
object, and the reduced thermal gradient between the
object and the air around it would allow the higher
portions of the object to hold their heat better. I
suspect this would be a pretty small difference, though,
unless it were a big object, with lots of heat.)
-Snail
Janet Kaiser on sun 4 nov 01
Thank goodness for that! Thanks John! You have relieved
me considerably. It is one thing being innumerate, but
another to learn one of the few laws learned in primary
school physics should be overturned too!
So it is "heat exchange" we are concerned with as
potters...? Another ball game altogether, hum?
As for the oceans... Well, they are indulging in
MASSIVE heat exchange. Just think about the cold and
warm currents around the globe. Our relatively mild
weather here in the UK is all thanks to the water
heating up in the Gulf of Mexico and crossing the
Atlantic as the Gulf Stream... It is pumped here by
cold water flowing down the whole east coast of
Canada/USA from the Arctic. The icebergs dropping into
the ocean propel the Labrador Current, which feed the
Gulf Stream which heats up and flows across the
Atlantic to the coast of Africa and Europe, displacing
cold water here and pumping it north to the Arctic...
The whole North Atlantic is like a huge self propelling
and temperature regulating jacuzzi pool, whilst
creating its own weather systems as a little
side-line... Same applies to the South Atlantic, the
North and South Pacific, the Indian Ocean... If that is
not impressive and colossal heat exchange, I don't know
what is. It is pretty mind-boggling and the scientists
still haven't worked out the dynamics of it all.
With all that swishing around (sorry, displacement) on
the surface of the oceans, no wonder there is neither
the time nor the inclination for vertical heat
exchange! However, it is cause for concern if things
start to go wrong... Like the polar icecaps melting
because of global warming...
Janet Kaiser - Just loved Joyce's post today too...
"Tide and time awaiteth no man". Reminded me of a funny
little incident here once upon a time...
We had friends visiting from inland Germany - never
been abroad before. They were taught at school all
about the moon, tides, etc. with specific reference to
the North Sea where acres of mud flats are exposed at
low tide and horse-drawn buggies take people from
island to island... Everyone has seen the photos and
films, heard the stories, etc. So their knowledge of
the coastline was specifically based on the North Sea,
what they had learned at school and reinforced by
popular imagery and folklore, right?
Imagine their first day here... I proposed having lunch
at a pub on the beach in an old fishing village which
is accessible over the headland at all times, or across
a small bay, but only when the tide is low. I said we
should drive over and depending how the tide was (in,
out, coming, going), whether we walk to the pub across
the sands or across the headland and back the other
way... Nice round trip... WELL!! They just would not
believe we had tides! Tides are a phenomena special to
the North Sea Coast of Germany!! They learned that at
school, so it MUST be true! Basta! They had not
realised they were only learning a principal applicable
to all oceans and tidal waters! I don't think they ever
forgave me for laughing so loudly, when I realised they
were being serious... I know. Shouldn't laugh when
people loose face, but I could not help it! They laugh
themselves now... "Remember when" stories. Good we can!
The Chapel of Art . Capel Celfyddyd
HOME OF THE INTERNATIONAL POTTERS' PATH
Criccieth LL52 0EA, GB-Wales Tel: (01766) 523570
E-mail: postbox@the-coa.org.uk
WEBSITE: http://www.the-coa.org.uk
----- Original Message -----
Darn you...... I said I wasn't going to post anything
else on this.
It isn't that hot air balloons go upward.... it is that
the ground moves
away from them. (Kidding....kidding!)
Your understanding is CORRECT..... hotter air DOES
rise! It is less
dense.....boyant in colder air....weighs less per unit
of volume. It
"floats". Or as has been pointed out..... the dense
cold air holds it up
.
This verbal gobbeldygook of mine has been revolving
around the distinction
between "hot air" and "heat energy".
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