Aim: How do celestial objects appear to move in the night

time sky? Do Now:

- Take the top worksheet from the back.

- Explain rotation and revolution as well as what they create for the Earth.•Rotation – the earth spinning on it’s axis. Day and Night, makes Foucault pendulum appear to change

direction.

•Revolution – the earth moving around the sun. The seasons and the Year

I. REMEMBER!

1) Rotation causes:

• objects in the sky to rise in the east and set in the west at 15O per hour.

2) Polaris is aligned with the North pole which causes:

• objects in the sky appear to move around Polaris.

• the altitude of Polaris to equal the latitude of the observer.

II. Celestial Sphere•Celestial Sphere – a “dome” around the

planet with celestial objects attached to it.

•Zenith – directly above an observers head.

•Horizon – intersection of the celestial sphere and the ground.

• Celestial objects are objects that can be seen in the sky that are not in the atmosphere.

III. The Seasons• Winter:

– Winter Solstice December 21st – Sun is directly over head at the Tropic Of Capricorn

(23.50 S)– Shortest Day Light Hours (about 9 hours

• Summer:

- Summer Solstice June 21st

- Sun is directly over head at the Tropic of Cancer (23.50 N)

- Longest Day Light Hours (about 15 hours)

• Spring and Fall:– Spring Equinox (March 21st) and Fall Equinox

(September 21st)– Sun directly over head at the Equator (00)– Equal number of day light and night time

hours.

Horizon

W

S N

E

Date: Hours of Daylight:

Position of SUNRISE: Position of SUNSET :

W

E

S N

Date: Hours of Daylight:

Position of SUNRISE: Position of SUNSET :

W

E

S N

Date: Hours of Daylight:

Position of SUNRISE: Position of SUNSET :

** The noon sun is highest in summer and lowest in winter.

IV. Moving ShadowsThe length and position of a shadow

depends on both the time of year and the time of day.