Moon, Eclipses, and Tides
Ms. Wood
General Moon Info
– Moon’s rotation 27.3 days
– Moon’s revolution around Earth – 27.3 days
– Same side of moon always faces earth hence “dark
side of the moon”
– One day on moon = one year on moon
– Moon reflects sunlight
– 1959 - first time people saw far side of moon
thanks to Soviet Luna 3
– From the moon, Earth goes through phases
Moon Phases
– Different shapes of
moon are called phases
– Moon goes through
phases in one month
– Phases are due to
changing relative
positions of moon,
earth, and sun
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New moon
Waxing Crescent
First Quarter
Waxing Gibbous
Full Moon
Waning Gibbous
Third Quarter
Waning Crescent
Eclipses
– Definition: Partial or total blocking of one object by
another
– Solar eclipse – blocking of sunlight to Earth that occurs
because the moon is between Earth and the sun
– Solar eclipse is like a new moon because it blocks the view
of the sun
– Only people in umbra can experience total solar eclipse –
see stars and corona (atmosphere of sun)
– Umbra – The darkest part of a shadow
– Partial eclipse can be seen in penumbra
– Penumbra – The part of a shadow surrounding the darkest
part
– Occur in new moon
Eclipses
– Lunar eclipses – the blocking of sunlight to the
moon because the Earth is between the moon and
the sun
– Lunar eclipses are much more popular
– Eclipse seasons can help astronomers predict
eclipses
– Occur in full moon
Tides
– Definition: The rise and fall of the level of water in
the ocean
– 6 hours rise; 6 hours fall
– Caused by Moon’s gravitational pull on earth
– 2 high tides on earth at once
– Low tide is from areas between the high tides
– 25 hour cycle of 2 high and 2 low tides
More Tides
• Shapes of bays, inlets, and ocean floor effect tides
• Neap tide – A tide with the least difference between
high and low tides
• The sun and moon pull in opposite directions
• Spring tide –A tide with the greatest difference
between low and high tides
• The sun and moon pull in the same direction
And Even More Tides
– Intertidal zone – under water in high tide but
exposed at low tide
– http://www.youtube.com/watch?v=l37ofe9haMU
– Animals here have:
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Constantly changing conditions
Powerful suction
Hard plates on shells
Examples
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Purple sea stars
Sand fleas
Crabs
Barnacles