The first goal is to set up a concrete
representation of the path the Sun follows in the sky
on the Equinox.
Other goals are:
understanding local time and true solar time understanding geometrical
relationship between latitude and solar latitude understanding
Earth,s seasons.
Materials needed:
A 1.4 m pole or a bamboo cane
A small eye balt to make sight
Bamboo canes (or other easily cut poles) 2,5 meters long (one
for each observation)
Hand-saw to cut bamboo canes lor poles
Hammer, shoves to put in ground meter stick, string.
Prepation:
Find a pole (bamboo pole, broom handle etc ) and attach a small
"eye bolt or other sight to
the top. It should be about 1,4 meters long. In a location with
a clear view of the southern
sky plant the sight pole into the ground such that once planted
its height 1,2 meters.
Around the pole dig a circular furrow 1 meter in radius (you
can trace the circle using a
1 meter length string tied to the base of the pole). The bamboo
canes will be stuck into the furow (so make sure the ground is
soft enough
and the furrow deep enough to accomadate the canes). The canes
should be 2,5 meters at
most.
You will need 1 cane per observation.
Procedure:
Each time you make an observation you will place the can in the
furrow along the
line-of-sight between the sight and the Sun and then cut it at
the height that marks the
Sun,s elevation in your sky.
Record the local time, true solar time, azimuth and the height
of the cane for each
observation (using a schedule).
Remember:
the height of the sight poles top is 1,2 m from the ground put
the canes in one at a time as you observe the sight is simple,
small ring put on top of a pole the experiment can be better
performed if at least two people take part in it : while one
looks through the sight his/her partner finds the right direction
of the sun (rays), with his/her
help, and then marks the sun,s altitude on a cane (as seen fom
the sight), that is so placed
in the furrow definitively.
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