any object in space outside of Earth's atmosphere stars, planets, Moon, Sun, comets model of the sky Z zenith Z - highest point in sky - directly above the observer's head horizon imaginary boundary between the sky and ground

II. Star Motions. 1. Looking up, the sky appears to be a ________ dome Watch a _______ rise. It moves in a wide _______. But one point in the sky __________________________ star arc star does not move. That point appears fixed. Later the star ________. It is as if the stars move on a ____________________ that ____________________ Earth on a _____________ _______. Half of the sphere is ______________________. sets transparent sphere rotates around gigantic axis hidden beneath you.

4. The fixed point that does not move is directly above _________ _______________________. It is near the star _________________. Its altitude above the horizon equals the __________________ of the observer. Polaris north on the horizon Polaris latitude rise 5. Some stars _________ and _____. See A and B at right. Other stars _______________ ____________. They circle the ____________ , and are called _______________________ stars. See star C at right . A set never rise and B C never set pole/axis circumpolar

Star C 350 Notice: -Star A is _______________________ -Most stars do NOT rise directly in the _________ and do NOT set directly in the ___________ -The latitude of this observer is ____________ circumpolar east west 350 N

Which direction are you looking in this picture?

Which direction are you looking in this picture?

How long was the exposure? What latitude is this?

Stars appear to rotate around Earth from _______ the spinning of Earth on its own axis W east west E 3600 24 3600 150 / hour 24 h Stars appear to rotate around Earth from _______ to _________ at a rate of ________________ because of Earth's _________________________________ east west 150 / hour rotation in the opposite direction.

circumpolar = Polaris 4 2 3 N E W NY Notice: _____ x 150/h = _________ between each position above mid October 6 h 1 900 2 3 4

D. 1. The stars, Sun, moon and planets move ______/h 150 D. 1. The stars, Sun, moon and planets move ______/h across the ________________________. celestial sphere = celestial object etc 9 am 8 am 150 Sun's path S N

from to hours degrees 8 am 9 am 1 10 am 2 pm 12 pm 4 pm 150 2 300 4 600 5 750 3 450 6 900

the same 2. Because all stars move across the sky at ___________ ____________ , any star with a ______________ path will be above the horizon for ____________________________. rate longer a longer time B C E S A N W Star A: __________ path  above horizon for _____ h Star B: rises/sets in _______  above horizon for _____ h Star C: __________ path  above horizon for _______ h longest > 12 E/W___ 12 shortest < 12

IV. Effects of Earth's Rotation 1. ___________________. As Earth rotates on its axis, half of it faces the sun and has daylight. The other half is in darkness and has nighttime. Night and Day view from above North Pole: light from the Sun Day Night

Earth rotates, so points on its surface rotate into and out of _____________: sunlight 6 am View from North Pole: 8 am 4 am 10 am sunrise 2 am light from the Sun 12 pm noon midnight 12 am sunset 2 pm 10 pm 4 pm 8 pm 6 pm 300 2 Meridians shown are ______ apart  every ______ hours (All times are approximate.)

2. Time – is based on Earth's _________, which causes the Sun to _______ and _______ rotation set rise imaginary line from N to S passing through the zenith Z local meridian - _____________________________________ _____________________________________ Z 12:00 p.m. -Sun is directly S - Sun is highest - looking south: local noon- __________ _______________________ 12 pm S a.m. p.m. N E S W Sun's path looking south

3. Change in Shadow Length. shadow of a pole - ________________________________ _________________________________ -points directly opposite the Sun -shortens in the a.m. -shortest at local noon and points N -lengthens in the p.m. top view 12 pm S 9 am 3 pm pole pole S 3 pm 9 am noon N N

This is the basis of sundials.

- Earth rotates _____ degrees every hour Earth's Time Zones - Earth rotates _____ degrees every hour - The Sun reaches local noon ______ degrees further__________ every hour - Time zones are ______ apart from each other 15 15 west 150 11 am noon 1 pm 2 pm Pacific Mountain Eastern Central

V. Evidence of Earth's rotation: Foucault Pendulum: ________________________ A pendulum swung in one direction (A-A') appears to change to a new direction (B-B') because Earth rotates underneath it 6 ___ hours later, Earth has rotated ______ degrees: Top view of pendulum at the North Pole: 90 Notice the Pendulum keeps the same direction ___________ A A' B B'

2. Coriolis Effect: ________________________________ ___________________________________________________ the apparent curving or turning of winds, currents and projectiles caused by Earth's rotation. = original path = curved path Turns to the _______ in Northern Hemisphere right The equator moves _________, than the poles. So projectiles curve _________ of the _________ path. faster direction of rotation in front Turns to the _______ in Southern Hemisphere original left Earth