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The Earth, Moon,and SunCh. 15
How Does Earth Move?•Earth moves in space in two
major ways: __________ and __________.– Earth _________ on its _______ (the
imaginary line passing through the N & S pole)
– Earth _________ around the _______ on an elliptical ________.
rotation revolutionrotates axis
revolves
sunorbit
How Does Earth Move?
•The __________ of Earth causes us to have ___________ every ______.
•The ________ of Earth every ______ ___ causes us to have a _________.
rotationday & night
24 hrs
revolution
365 ¼day
year
The History of the Calendar:
•___________:– based their calendar on star
motion and calculated about 365 days. They broke them into 12 months with an extra 5 days at the end.
Egyptians
The History of the Calendar:
•__________:– Used the Egyptian calendar but
adjusted it to add ¼ of a day (“leap year”).
Romans
The History of the Calendar:
•__________:– The calendar we use today, based
off the Roman calendar but adjusted by 11 minutes a year.•Named after Pope Gregory XII
Gregorian
Planetary Movement
What Causes the Seasons?
•The sun rays hit’s Earth’s surface ________ (more at the ______ than at the ____).
•Earth has _______ because its _____ is tilted at ____ degrees as it revolves around the sun.
unevenly Equatorpoles
seasons axis23.5
Earth’s Seasons• The sun appears farthest north once
a year and farthest south once a year; this is known as the _______.
• In the Northern Hemisphere when:– the sun is farthest ______ it is the
_______ solstice (around ______ 21st) and we have the longest day.
– the sun is farthest ______ it is the _______ solstice (around ______ 21st) and we have the shortest day.
Dec.
north summerJune
south winter
solstice
Earth’s Seasons
•Halfway between the solstices neither hemisphere is tilted toward the sun, and we have __________in the day and night. This is known as the _______. – the _______ (or spring) occurs around
______ 21st
– the ________ (or fall) occurs around ______ 21st Sept.
equinoxvernal
Marchautumna
l
equal hours
Seasons in the N and S
The Earth & Moon
Ch 15 Lesson 2
The Moon Dance
The Moon’s Formation
Rotation and Revolution
• The Moon rotates on its axis and revolves around the Earth, just as the Earth revolves around the Sun.
• The Moon’s rotation takes 27.3 days around Earth.
• It takes about 29.5 days for the Moon to complete the cycle of phases.
Moon Phases• Moon phases are the different forms that
the Moon takes in its appearance from Earth
• There are 4 main phases of the Moon: – New: occurs when the Moon is between
Earth and the Sun– Waxing: means that more of the half
moon can be seen each night– Waning: means that less of the half
moon can be seen each night– Full: occurs when all of the Moon’s
surface facing Earth reflects light
Moon Phases
Moon Phases…cont.
Eclipses• There are two types of eclipses
– Solar eclipse: occurs when the Moon moves directly between the Sun and Earth and casts its shadow over part of Earth•Umbra: the darkest part of the Moon’s shadow
•Penumbra: a partial solar eclipse seen from Earth
– Lunar eclipse: when Earth’s shadow falls on the Moon
Total Eclipse
Solar Eclipse
Lunar Eclipse
The MoonIt’s Affect on the Oceans
• The Earth and the Moon are attracted to each other like magnets. The Earth has a gravitational field that holds objects to it’s surface, but water is always moving therefore can not be held down.
• Tides are the periodic rise and fall of the ocean waters. High and Low tides occur because of the Moon’s gravitational pull.
• The ocean moves between high & low tides, about 12 hours 25 minutes b/w the two.
Spring & Neap Tides
Spring tide: When the Earth, Moon, and Sun are aligned to cause exceptionally high and low tides. This happens during the Full and New Moon.
Neap tide: Smaller difference between high and low tides that occur during quarter phases.
Moon & Tides
High Tide
Low Tide
The Importance of Understanding the Tides
• Commercial and recreational fisherman use their knowledge of tides and tidal currents to help them improve their catches.
• Ships navigating through shallow water ports and waterways must be knowledgeable of the time and height of the tides as well as the speed and direction of the currents.
• Oceanographers study tidal fluctuations to better understand the ocean circulation and relationship to world climate issues.
