Miso Soup Convection Demonstration
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Purpose: To illustrate the physics and
appearance of the convection taking place
in the Sun's interior.

Prerequisities: Show graphics of the 
sun's interior, and discuss the
different means of energy transport.

Materials needed per student (or pair
or group, depending on how you want
to run this):
1 plastic miso bowl
1 plastic spoon
1 packet of instant miso soup
boiling water

1. Boil the water. It's got to be
piping hot for this to work properly.

2. Put the miso (use aka or shiro, but 
not osuimono; the miso paste is best)
into the bowl. Leave the veggies out
if you can.

3. Pour the hot water into the bowl,
stir well once (preferably not in a 
circular motion), and stand back.

Results: You will see convection cells
forming, and you will see the upward
and downward motion of these cells as
they transport heat to the surface.
Not only is the physical process the
same as in the Sun, but the appearance
is uncannily similar as well.

Why does this work?
Miso is made of particles small enough
to be able to float along the convection
cells and hence make them visible. But
the particles are big enough to be seen
by our eyes without fancy gadgets.

Origin of this little demo? 
A bunch of astronomy geeks went to a 
Japanese restaurant after work. The
waitresses are probably still talking
about the weirdos who kept staring at
the bowls of miso with expressions of
enlightenment.