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Seasons
Catalyst What is the redshift, and how does it
provide evidence for the Big Bang? What is the difference between the
heliocentric and geocentric model? Venus is one planet closer to the Sun than
the Earth. What can we conclude about the length of Venus’ year, compared to the Earth’s?
Write in complete sentences!
Don’t talk during the Catalyst!
Objectives
By the end of today, all SWBAT…State that the Earth’s axis is tiltedDescribe the difference in intensity between direct and indirect sunlight
Explain how the tilt of the Earth’s axis produces seasons
Agenda
Stand up and pair up Notes:
Earth’s basics Tilt Direct and indirect light Seasons
Classwork: Images and Critical Questions Bingo Homework????
Earth and Sun
Key Point #1: The Earth revolves AND rotates counterclockwise around the Sun
As we already know, the heliocentric model states that the Earth revolves around the Sun
Take a look at the earth’s orbit again.
What do you notice?http://www.classzone.com/books/earth_science/terc/content/visualizations/es0408/es0408page01.cfm?chapter_no=04
Tilt of the Earth Key Point #2:
The tilt of the Earth causes different parts of the Earth receive sunlight of different intensity
The Earth is tilted 23.5º degrees
Flashlight Demo
Look at the flashlight beam when it is shined directly over the paper and look at the beam when it is shined at an angle.
Which beam is more intense?
Direct and Indirect Light
Direct light: light that hits the earth “straight on”
--Concentrated, strong
Indirect light: light that hits the earth at an angle
--Spread out, weaker
Key Point #3: The tilt of the Earth’s axis causes there to be seasonsHemisphere TOWARD Sun = SUMMER
Hemisphere AWAY from Sun = WINTER
Season N: ________________
Season S: ________________˘
Season N: ________________
Season S: ________________˘
Season N: ________________
Season S: ________________˘
Season N: ________________
Season S: ________________˘
Think about this…
Why is the North Pole always experiencing winter?
The North Pole is always cold because it always receives indirect rays that are less intense.
The North Pole is always cold because it always receives indirect rays that are less intense.