Rotation vs. Revolution •
____________________ is the spin of an object about its axis. –
•
The Earth rotates once a day (once every 24 hours).
___________________ is the orbit of one object around another. –
The Earth _________________ around the Sun every ____________ days.
Solar Heating
The __________ or any light, heats a surface most effectively when it is shining _______________ onto the surface.
What Causes Earth’s Seasons? •
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Earth’s __________ is tilted 23.5 degrees – it always points in the same direction (_________________, the North Star) as we _____________ our Sun once a _____________
This tilt causes the __________________________ to alternate in the amount of our Sun’s light and heat they receive through the year
Seasons vs. hemispheres
Northern and southern hemispheres have_____________________ seasons
Seasons
In ________________, the sun is at a smaller _______________, more effective heating.
In ________________, the sun is at a larger angle, ___________
effective heating.
Seasons Misconception (2 slides) •
Many people carry the misconception that the ______________ are due to the distance of the ____________ from the ________ . However, consider the following facts: –
The Earth’s orbit around the Sun is nearly a perfect ____________. The Earth is slightly closer to the Sun in __________________ and farther from the Sun in ____________.
•
•
–
_________________________ (closest to the Sun) is around January 3 when Earth is about 91,405,436 miles from the Sun.
Aphelion (___________________ from the Sun) is around July 4 when Earth is about 94,511,989 miles from the Sun.
(SLIDE 2) While it is winter in the ______________________ hemisphere it is summer in the Southern hemisphere. If the seasons were due to our distance from the Sun both hemispheres would have the same ___________________ at the same time.
Earth’s orbit is almost a perfect circle • •
Earth is ________________ to our Sun (91 million miles) in _______________—January 3
Earth is ________________ from on our Sun (94 million miles) in _______________ –July 4
Equinox • • • • •
Sun rises due ________ Sun _______ due west
Exactly _____ hours of day, 12 hours of _________ Once in _________ Once in _________
• When the sun is ________________ over the ____________________.
Solstice •
Summer___________________ :
• •
Longest ________________ of the year
•
_______________ solstice:
• •
Sun at noon is ____________________ in the sky ___________________ daylight of the year
Sun at noon is ________________ in the ________