The Book of Stars: Being a Simple Explanation of the Stars and Their Uses to Boy LifeCollins, A. Frederick (Archie Frederick)
Science
The Book of Stars: Being a Simple Explanation of the Stars and Their Uses to Boy Life
Collins, A. Frederick (Archie Frederick)
Astronomy -- Juvenile literature; Stars -- Juvenile literature
Now slowly turn your body round to the left and always hold the orange
with the peeled side toward you. You will see that the light from the
lamp striking the orange forms a crescent with its horns pointing away
from the light.
Keep on turning, a little at a time, and soon a quarter of the orange
will reflect the light and this is like the first quarter of the Moon.
When you have turned nearly halfway round nearly half of the orange
will shine by the reflected light of the lamp and you will have a fair
example of the gibbous Moon.
When you have turned your back to the light hold the orange above your
head so that your shadow will not hide it; now half of the orange—the
half that is peeled—reflects the lamp-light and represents the Moon
when it is full.
[Illustration: FIG. 111.—BOY, LAMP AND ORANGE SHOWING PHASES OF MOON.]
As you keep turning round the amount of light reflected by the orange,
which you can see grows less and less, the bright part at first being
gibbous, then the last quarter is seen, after that a thin crescent,
and finally when you have turned completely round the orange is again
between your eyes and the light, hence it can no longer be seen, and
the new Moon phase is again at hand.
=The Harvest and Hunter’s Moon.=—You will remember that on September
21 the days and nights are equal and this is called the _Autumn
Equinox_. The full moon that falls nearest to September 21 is called
the _Harvest Moon_ as it rises at nearly the same hour for several
nights in succession and this makes several long moonlight evenings in
succession. The _Hunter’s Moon_ follows the Harvest Moon.
=How the Moon Makes the Tides.=—When we are at the seashore we soon see
that there is a regular rise and fall of the ocean.
This rise and fall of the waters is called the _tide_, and if we note
the time when the waters have reached the highest point—which is called
_high tide_—we will find that a little over six hours later the waters
have reached their lowest point—or _low tide_.
Before the tide has reached the high point again another six hours and
some minutes have passed so that from one high tide to another high
tide 12 hours and 25 minutes have elapsed. These tides are chiefly
caused by two forces acting on the oceans, one being the attraction of
the Moon for the Earth, and the other being the centrifugal force set
up by the Earth’s motion round its axis.
The effect of the Moon’s attraction for the Earth is to pull the water
of the ocean on the side of the Earth nearest it, and this forms a
bulge, or great wave, while on the other side of the Earth the Moon’s
attraction is smaller for the water than it is for the solid Earth,
so the Earth is pulled away from the water. Thus two tidal waves are
formed at the same time, one on each side of the Earth, as shown in
Fig. 112.
[Illustration: FIG. 112.—ATTRACTION OF THE MOON CAUSES THE TIDES.]
Public-domain text, read in full here on John Shaqi.
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