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This kinesthetic activity models the life of a large star
that is many times the mass of our sun. Each person involved in this activity
represents a bit of the material that goes into making such a star.
As the activity begins, everyone is dancing or moving around freely,
just bits of matter that are hanging out in some particular spot in space.
As these bits of matter come close to one another they start clumping together more and
more due to gravity. After a while this matter is clumped
tightly enough to form a star. In our activity the participants at the
edges form a ring facing inward as the outer shell of the star, with their hands
raised to represent the inwardly directed force of gravity. The
participants in the center face outward representing the core of the star with their
hands also raised to represent the energy generated by the fusion of hydrogen at the
center of the star. These two forces remain in balance
for most of the star's life; we call this a main sequence star.
Eventually, the star runs out of hydrogen to
fuse in the core, and the balance of gravity and energy from fusion is broken.
When this happens gravity wins, and the participants in the core of the
star drop their hands and move slightly closer together. The
participants in the shell never lower their hands as gravity is always in effect.
The slight decrease in the size of the core makes it hot and dense enough to start
fusing helium. The participants in the core raise their hands once more
as energy is again being generated at the center of the star. Participants
in the shell take a step outward to represent the surge in energy making the star
larger than it was during the main sequence phase. The star
has become a red giant. Eventually the core
of the star runs out of helium to fuse. When this happens the participants
in the core once again drop their hands and move slightly closer together.
Like before, the decrease in core size makes the core hot enough to start the
next level of fusion. The participants in the core raise their hands once
more. Participants in the shell again take a step outward to represent another
surge in energy making the star even larger. With the largest
stars, this process repeats several more times until finally the core of the
star is made of iron. This time when the core runs out of fuel
for fusion the participants at the core drop their hands and once again move
closer together, but this time there is no next level of fusion.
As fusing iron actually takes energy instead of generating energy.
The force of gravity wins out and the participants in the shell move inward
as the star begins to collapse. As this happens the core gets denser
and heats up so the participants in the core give one last big push
as they move even closer together. The participants in the shell move
inward, hit the core's final push of energy and rebound, exploding out into
space in what we call a supernova explosion. This shell material is
now available to be used in the formation of another star.
The remaining participants from the core now get as close together as possible as the core
collapses in on itself. They represent the neutron star or black hole
that is left behind.
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