Planetary Motion BLM 13.3a, 13.1 a,b,c

Earth’s Rotation Rotation – the spinning of an object around it’s axis. Axis runs North to South. One rotation of the Earth takes 24 hours. (East) This motion causes most stars (and the Sun, Moon, and planets) to appear to rise in the east and set in the west. BLM 13.3

Earth’s Revolution Revolution – the movement of one object travelling around another. It takes the Earth one year to travel, or revolve, in a circle around the Sun counter-clockwise. This motion allows us to see different constellations during different seasons.

The Equator An imaginary line that circles the middle of the Earth East to West. This is the Equator in Kenya, Africa altitude 6389 ft. 1990

Questions Why do we only see certain stars and constellations during certain seasons? The Earth’s Revolutions. Why do we have seasons? Why does the Sun rise and set and the Moon rise and set? The Earth’s Rotations. BLM 13.3a

13.3a

Demonstration Day/Night – angle affects the amount of daylight. Seasons – angle affects the type of season. Stars are only seen during certain seasons.

Star Map (See text 406-407)

Winter Star Chart (13.1a) (Map the following constellations)

Fall Star Chart (13.1b)

Spring Star Chart (13.1c)

Constellations Lab tomorrow. Pencil Eraser Ruler