Page #136Feb. 5, 2013 Focus: Day & Night, Seasons, Rotation & Revolution Objective: explain how the...
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Transcript of Page #136Feb. 5, 2013 Focus: Day & Night, Seasons, Rotation & Revolution Objective: explain how the...
Page #136 Feb. 5, 2013Focus: Day & Night, Seasons, Rotation & RevolutionObjective: explain how the movement of the Earth affect different cyclesEQ: In what ways do planets move? What is affected by this movement? HW: lesson review questionsWarm Up: 1. What is gravitational pull and how does it affect our solar system? 2. How do we get day and night?
OH Last Class!
Why do the planets revolve around the sun?What would happen without gravity?What is gravitational pull and how does it affect our solar system?
http://www.youtube.com/watch?v=RIBNgx2hlyU
Day & Night
Thinking Ahead
• What is a day?
• What is a year?
• Are days and years the same on other planets? Why do you think so?
http://player.discoveryeducation.com/index.cfm?guidAssetId=D621326A-36AB-47BF-9CC7-77BE8EB7589A
• DIRECTIONS:
• 1. Color and label the sun
• 2. Color the day time half of the Earth green and blue
• 3. Color the night time half of the Earth black
The Earth spins on its axis
• The spinning is called ROTATION
• The direction of rotation is counterclockwise if you are looking at it as if you were floating over the North Pole
http://vortex.plymouth.edu/sun/sun.html
Each morning, the sun rises in the east and sets in the west.
Read more: http://www.universetoday.com/18117/why-does-the-sun-rise-in-the-east-and-set-in-the-west/#ixzz2JxtfwWlH
As the Earth spins, part of the Earth is facing toward the Sun,
and part is facing away from the Sun.
The part of the Earth facing the Sun has daytime
Day and Night
• The Earth rotates around once in 24 hours
• The time it takes the Earth to rotate completely around once is what we call a day.
• It's Earth's rotation that gives us night and day
• http://www.onr.navy.mil/focus/spacesciences/observingsky/motion1.htm
So the reason we have day and night is because the Earth rotates.
Rotate means
to turn.
The Earth rotating on its ______gives us day and night.
axis
Earth’s axis is
the imaginary line that goes through the center of the Earth.
Rotation
Rotation: Planets spin on an axisOne Rotation = DayFast Rotation = short daySlow Rotation = long day
Rotation is measured in hours.Earth’s Rotation: 24 hours (1 day)
But guess what! Rotating isn’t the only way the Earth moves in space!
The Earth also revolves.
Revolve – When one object moves around another object
It takes the Earth one year, or 365 ¼ days to orbit the sun.
Does anyone know what orbit means?
Orbit -
The path that an object follows as it revolves around another object.
How long does one revolution take?
RevolutionRevolution: Planets revolve around the
sunRevolution = YearFast Revolution = short year
You would be olderCloser to the sun
Slow Revolution = long yearYou would be youngerFarther from the sunRevolution is measured in _days___Earth’s Revolution 365 days (1 year)
Planet Callisto Ganymede Europa Dione
Rotation Period (hours)
36 hours 567 hours 909 hours 3,085 hours
Revolution Period (days)
6,396 days 350 days 2,349 days 54,938 days
Other planetsOther planetsWhich planet do you think rotates the Which planet do you think rotates the
fastest? Why? fastest? Why? Which planet do you think has the longest Which planet do you think has the longest
revolution? Why? revolution? Why?
Rotation DataRotation Data
Planet Length of Day
Mercury 58.6 Earth days
Venus 243.02 Earth days
Earth 24 hr
Mars 24 hr 37 min
Jupiter 9 hr 55 min
Saturn 10 hr 32 min
Uranus 17 hr 14 min
Neptune 16 hr 6 min
Rotational SpeedsRotational Speeds
Planet Length of Day Rotational Speed
(km/h)
Mercury 58.6 Earth days 10.9
Venus 243.02 Earth days 6.5
Earth 24 hr 1670
Mars 24 hr 37 min 867
Jupiter 9 hr 55 min 45600
Saturn 10 hr 32 min 37000
Uranus 17 hr 14 min 10900
Neptune 16 hr 6 min 8460
RevolutionsRevolutions
Why are the revolutions of each planet different than Earth’s Why are the revolutions of each planet different than Earth’s revolution? revolution?
•Smallest planet
•Closest to Sun, moves around fastest (88 days)
•no tilt of axis so poles are cold
Mercury
Venus • Nearly the same size as Earth
• Slowest rotation of any planet (243 days)
• Spins backwards
Can see it in the night sky without a telescope!
EarthLiquid water – lots! - at
surface
23 degree axis tilt (seasons!)
Earth’s Rotation:
24 hours (1 day)
Earth’s Revolution:
365 days (1 year)
Can see it without a telescope!
25 degree axis tilt (seasons!)
Rotates once every ~24 hours and orbits the Sun once every 687 days
Very cold
No liquid water at surface; ice in poles
Mars Can see it in the night sky without a telescope!
diameter – 11x Earth
largest planet completes one orbit in 4,333
Earth days, or almost
12 Earth years. Jupiter rotates faster than any other planet. It
takes 9 hours 56 minutes to spin around once on its axis, compared with 24 hours for Earth.
Which means it has the shortest day.
Jupiter
•9x the size of Earth
•11 hour rotation / 29 year orbit
Saturn
Seasons
What do think causes the seasons?
http://nix.ksc.nasa.gov/info
What Causes Earth’s Seasons?
• Earth’s axis is tilted 23.5 degrees – it always points in the same direction (Polaris, the North Star) as we orbit our Sun once a year
• This tilt causes the hemispheres to alternate in the amount of our Sun’s light and heat they receive through the year
http://www.lpi.usra.edu/education/skytellers/seasons/about.shtml
More daylight hours, more direct sunlight
Northern Hemisphere Summer
http://www.lpi.usra.edu/education/skytellers/seasons/about.shtml
But why do we have four seasons?
It’s because the Earth’s axis is tilted.
Take a good look at our globe. It‘s not tilted like that because it looks nice. No way. That’s the way the Earth is tilted in space.
That tilt gives us seasons!
Look at this diagram. Notice how the Earth is always tilted in the same direction. As the Earth __________ the part of Earth tilted toward the sun changes.
revolves
During part of the year, the North Pole points
away from the sun. This season is _.winter_____
During part of the year the North Pole tilts
towards the sun. This season is
________.summer
When the North Pole is tilted toward the Sun, the Sun travels higher overhead in the sky. The Sun’s rays shine straighter down on that part of the Earth. It is summer in that part of the Earth.
It’s like pointing a flashlight at a piece of paper. When you hold the flashlight straight above the paper, the rays from the flashlight shine down straighter.
When the North Pole is tilted away from the Sun, the Sun stays lower in the sky. It is then winter in that part of the Earth.
If you point your flashlight at a piece of paper at an angle, the rays from the flashlight spread out.
In the Spring and Fall
http://k12.ocs.ou.edu/teachers/reference/equinox.gif
EQUINOXEQUINOX
A day lasts 12 hours and a night lasts 12 hours at
all latitudes.
Sunlight strikes the earth most directly
at the equator.
In the Summer and Winter
http://k12.ocs.ou.edu/teachers/reference/solstice.gif
SOLSTICESOLSTICEDuring the winter the Northern Hemisphere day lasts fewer
than 12 hours and the Southern Hemisphere day lasts more than 12 hours.
During the winter solstice, the North Pole has a 24-hour night and the South Pole has a 24-
hour day.Sunlight strikes the earth most
directly at the Tropic of Capricorn.
In the Summer and Winter
http://k12.ocs.ou.edu/teachers/reference/solstice.gif
SOLSTICESOLSTICE During the summer solstice the Northern Hemisphere day lasts
more than 12 hours and the Southern Hemisphere day lasts
fewer than 12 hours.
During the summer, the North Pole has a 24-hour day and the South Pole has a 24-hour night.
Sunlight strikes the earth most directly at the Tropic of Cancer.
Because the Earth is tilted, different parts of the planet get different amounts of sunlight at
different times of the year.
Why does the earth experience seasons?
Independent Practice
A.
B.
1. Draw pictures A and B.
2.Label the picture that shows the red dot is in the season of summer. Label the picture that shows the red dot in the season of winter.
http://ithacasciencezone.com/earthzone/lessons/07meteor/daylight.jpg
Page # January 17, 2011
Title: Rotation and Revolution
Objective: analyze how Earth’s movement affects day and night
HW: all work is due by Wednesday, check calendars
Warm-Up:
Does the Earth move around the Sun?
How do we get day and night?
RIGHT PAGE 52December 2, 2008
Title: Lets Start a Revolution !Objective: Describe a planet and the effects of a planet’s movement.Words to Know:- orbit - path of an object in space as it moves around another object.year- amount of time a planet takes to revolve around the sun.day- how many hours does it take a planet to rotate on its axes.