Earth moves through space in two ways: revolution and
rotation.
Slide 3
Rotation It takes 24 hours for Earth to rotate one time on its
axis. This 24 hour period is also called a day. The earth rotates
west to east. This make the sun appear to rise in the east and set
in the west. http://www.learner.org/jnorth/images/graphics/mclass
/jr/Day2/Day_Sol_S21_RevolvingEarth.gif
http://www.learner.org/jnorth/images/graphics/mclass
/jr/Day2/Day_Sol_S21_RevolvingEarth.gif
https://www.youtube.com/watch?v=jtJkHlKBE1Q&fea ture=youtu.be
https://www.youtube.com/watch?v=jtJkHlKBE1Q&fea
ture=youtu.be
Slide 4
Revolution It takes 365 days or one year for Earth to revolve
around the sun. This is why stars and constellations appear in
different places throughout the year. The path an object takes
while it revolves is called its orbit.
https://www.youtube.com/embed/R2lP146KA5A?autopl
ay=1&enablejsapi=1&wmode=transparent
Slide 5
The constellations seem to change location in the sky
throughout the year. Whats really moving?
Slide 6
Revolution Because revolution is not exactly 365 days, we have
to add one day to the calendar every four years. This is known as
leap year. 1 orbit= 365 days + + + = 1 added day
Slide 7
Gravity and Inertia How do the Earth, moon, and other planets
stay in orbit? gravity and inertia
Slide 8
a. Gravity is a force where twoobjects are attracted to each
other. b. Inertia is the resistance of an object to change its
state of motion. c. Gravity pulls an object toward another object,
but inertia pulls it away.
Slide 9
Gravity and Inertia http://studyjams.scholastic.com/studyja
ms/jams/science/solar-system/sgravity- and-inertia.htm
http://studyjams.scholastic.com/studyja
ms/jams/science/solar-system/sgravity- and-inertia.htm
Slide 10
Ticket Out The Door 1. Define rotation. 2. Define revolution.
3. Which motion makes the sun appear to rise in the east and set in
the west each day? 4. Which motion makes the constellations in the
sky appear to move throughout the year? 5. What force keeps the
earth from crashing into the sun?
Slide 11
Answers: 1. the spin of an object on its axis 2. an object
makes one complete circle around another 3. rotation 4. revolution
5. inertia
Slide 12
Seasons The Earth is tilted at 23.5 degrees on its axis, and
this is why we have seasons. As Earth Revolves around the sun,
different hemispheres will be receiving more or less direct
sunlight based on whether the pole is tilted toward or away from
the sun.
Slide 13
Seasons Whatever season is occurring in the Northern
hemisphere, the opposite season will be occurring in the southern
hemisphere. An Australian Christmas card
http://www.youtube.com/watch?v=Pgq0LTh W7QA
http://www.youtube.com/watch?v=Pgq0LTh W7QA
Slide 14
Seasons Yardstick practice
Slide 15
Solstices Solstices are the two days of the year on which the
sun reaches its greatest distance north or south of the equator.
The days are longer around the summer solstice (around June 21-22
in the northern hemisphere) and shorter around the winter solstice
(around December 21-22 in the northern hemisphere).
Slide 16
Summer Solstice at the North Pole!
http://www.youtube.com/watch?v=ZZcaf g-meJA
http://www.youtube.com/watch?v=ZZcaf g-meJA
Slide 17
Equinoxes The equinox is either of the two days or periods each
year when the sun crosses the equator and day and night are of
equal length of twelve hours. During an equinox, neither hemisphere
is tilted toward or away from the sun. The spring or vernal equinox
happens around March 20-22, and the autumnal or fall equinox occurs
around September 22-23 in the northern hemisphere (and vice-versa
in the southern hemisphere).
http://esminfo.prenhall.com/science/geoanimat
ions/animations/01_EarthSun_E2.html
http://esminfo.prenhall.com/science/geoanimat
ions/animations/01_EarthSun_E2.html
Slide 18
Slide 19
Moon Motion a. It takes about 28 29 days for the moon to
revolve around Earth. b. It takes about 28 29 days for the moon to
rotate on its axis. c. Since the revolution and rotation take the
same amount of time, we always see the same side of the moon from
Earth.
Slide 20
Slide 21
Moon Phases The phase of the moon you see depends on how much
of the sunlit side of the moon that faces Earth. As the moon
revolves around the Earth, the amount of light that we can see
changes.
Solar Eclipses What is a solar eclipse? A solar eclipse happens
when the moon comes between the Earth and sun, blocking the suns
rays from the Earth. (The Earth is passing through the moons
shadow. In other words, a shadow is covering the sun.) A solar
eclipse can only happen during a new moon. Observe solar eclipses.
Observe solar eclipses.
Slide 35
Solar Eclipses A total eclipse is when the sun is completely
darkened. The moon is 400 times smaller than the Sun, but the moon
is also 400 times closer to Earth, so from Earths point of view,
the entire sun is blocked. The moons shadow only covers a small
area on Earths surface; therefore, only a small section of Earth
will be able to observe and experience the eclipse.
Slide 36
Solar Eclipse Animation
Slide 37
A picture of a 1999 solar eclipse taken from a satellite in
space.
Slide 38
Solar Eclipse Video https://www.youtube.com/watch?v=_201
ttTSG30 https://www.youtube.com/watch?v=_201 ttTSG30
Slide 39
Lunar Eclipses What is a lunar eclipse? A lunar eclipse occurs
when the Earth blocks the rays of the sun from the moon. (The moon
passes through the Earths shadow. In other words, a shadow is
covering the moon.) A lunar eclipse can only happen during a full
moon. A total eclipse happens when the moon is completely
blocked.
Slide 40
The moon is in Earths shadow.
Slide 41
Slide 42
Lunar Eclipse from Earth
Slide 43
Lunar Eclipse Video https://www.youtube.com/watch?v=49O
2MsT1txU https://www.youtube.com/watch?v=49O 2MsT1txU
Slide 44
Why dont eclipses happen every month? Most of the time the
distance of the shadow is too short to reach the earth or the
moon.
Slide 45
Also The orbit of the moon is at a 5 degree angle to the orbit
of the earth.
Slide 46
Can other planets have eclipses? Yes! A picture of Jupiter and
its moon Lo taken by Hubble. The black spot is Lo's shadow.
Slide 47
Spring Tide When the Earth, moon, and sun are in a straight
line during new and full moons, a spring tide occurs. The tidal
range is greatest. (High tide is higher than normal, and low tide
is lower than normal. You will see the greatest differences between
high and low tides during a spring tide because the sun and moons
gravity are working together.)
Slide 48
Slide 49
Neap Tide When the Earth, moon, and sun are forming a right
angle during the 1 st quarter and 3 rd quarter moons, a neap tide
occurs. The tidal range is lowest. (There isnt much difference
because the high tide is lower than normal and low tide is higher
than normal).
