The document discusses how the moon affects tides on Earth and appears to change shape from our perspective. It explains that the moon always looks half lit and half dark from space because it rotates, while from Earth it seems to change shapes throughout its monthly cycle. The moon's gravitational pull, combined with the sun's, causes bulges in the ocean that create tides, with the largest tides occurring during spring tides when their forces align.

1. Sunday, September 7th
, 2008
SPACE
The Lunar Cycle and
Tides

2. The Moon
 For centuries, human beings
have been fascinated by the
moon…by the way it changes
shape, causes our tides, and
creates eclipses.
 A cow has jumed over the
moon…and an old man lives on
it.
 Humans have worshipped the
moon, feared the moon, and
created numerous superstitions
about the moon.
 It has even been known to alter
human behaviour (people have
been known to go “looney”)

3.  While these stories are
interesting, they don’t really
help us understand what
happens.
 We only see the Moon
because sunlight reflects back
to us from its surface.
 The moon looks like it’s
changing shape all the time
(moon phases), but that’s just
what it looks like to us on
Earth.

4.  In reality, from space, the
moon always looks the same,
half light, and half dark.
 This is because half of the
moon is always facing the sun
and the other half is in
shadow.
 But for us on Earth, it looks like
it’s changing shape because
the moon is orbiting around us.
 Animation

5.  It takes 29.5 days for the
moon to make one
complete lunar cycle (or
one month)…
 …and the only time we
get an accurate view of
the moon is at the half
moon each month.
 Animation

6. Use the smart board pen to colour in the phases of the moon as they
appear to us on Earth, (#1-8) or colour in the phases on your own
worksheet.

7.  One last animation, just to be sure.

8. Tides
 The moon also affects the
tides in our oceans as it
revolves around the earth.
 The gravitational pull between
the Earth and the moon and
the Earth and the sun, create a
bulge of water every day.
 When the gravitational forces
of the moon and sun combine
to pull in the same direction we
get our biggest tides (spring
tides)…
 …and we get our lowest tides
(neap tides) when these forces
pull in different directions.