Designing, Making and Testing a Sundial
Introduction:
The sundial is the oldest know device for measuring time. The first
confirmed uses of it where by the Babylonians in around 2000BC.
However it is safe to say that shadows have been used as a rough
measure of time ever since primitive man discovered that as the day
progresses the shadows of trees and rocks get shorter and then longer
again.
The sundials used by the Babylonians were hollow half spheres, set
with edges flat and with a small bead at the centre. As the day wore
on the shadow of the bead followed a circular arc, which is divided
into 12 "temporary hours" (they changed through the seasons).
A modern sundial consists of a plane (dial face) and the gnomon
(style). The dial face is divided into hours and the gnomon is the
flat piece of metal, or stick in the dials centre, it points towards
the North Pole (in the northern hemisphere) or South Pole (in the
southern hemisphere). The gnomon must tilt at the angle of the
latitude at the location.
Although a sundial seems like a simple device for measuring time, it
is not. One cannot simply look at the shadow and find the time.
Firstly the sundial will show local time, not GMT. Secondly we must
allow for the 'equation of time.' Because the Earth's orbit is not
circular, its velocity changes at the perihelion. To allow for this
would be awkward, so we use a 'mean sun.' The equation only rises as
high as 16 minutes. It is the same every year, and on 4 dates it
becomes 0.
A minus sign indicates that the clock is ahead of the sun, a plus that
it is behind the sun.
Clock time = (sundial time) - (equation of time)
For example: Sundial time = 10:00am
===================================
Date= January 9th
Equation of time= -7
Clock time = (sundial time) - (equation of time)
= 10:00 - (-7)
would appear to be big and old, probably scarred from weather and time, as a tree might look.
· A south line can be found midway between the hour hand and 1200 hours. If in doubt as to which end of the line is north always remember that the sun is in the east before noon and in the west in the afternoon.
this case I will time how long it takes for the water to reach the ’50
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and ‘no’, or ‘good’ and ‘bad’ side. Like the Chinese Yin and Yang sign, abortion
There are many ways in which scientists and researchers try to understand the molecular uniqueness and physiology of living organisms. One of these ways is the Circadian clock, this clock transfers the physiology and behaviors of mammalians into rhythms that are coordinated with the 24hr solar system. This system can be affected by environmental factors such as the food, temperature and parasites. The circadian rhythms play a role in gene expression to produce protein. Gene expression is displayed through the central dogma of (DNA RNA protein). How the clock work with the 24hr solar day is that it allows gene expression every 24hr to tell when a physiological process is most active. And any damage made to the DNA is more effective
This is symbolic to the sunrise in the east and sunset in the west because light means life and
a couple of hours. The Liberty Bell was nearly always met with military salutes, parades,
the better part of a day, and spawns a fatal manhunt. His conflict with the
They come in various colors and brands and are similar to a bear in shape.
of the “sun” (5) grants us to see time in its shape, it cannot aid in its passing and they can
Another suggestion that may form a similar image is by heating a sculpture at a certain degree and place the cloth on it for a specific amount of time.
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...xhibit the usually pattern common to a small magnet as shown below in fig 1.