Earth in Space Ch. 1, Section 1 Page 6 - 13

I. Earth in Space a. The study of the moon, stars, and other objects in space is called __ASTRONOMY__ A. HOW EARTH MOVES a. The 2 major ways Earth moves through space is __ROTATION__ and __REVOLUTION__

1. Rotation a. The imaginary line that __PASSES__ through Earth’s center and the __NORTH__ and __SOUTH__ poles is Earth’s __AXIS__ b. The __SPINNING__ of Earth on its axis is called __ROTATION__ c. __ROTATION__ causes __DAY__ and __NIGHT__ d. It takes the __EARTH__ 24 __HOURS__ to rotate once, which is called a __DAY__ BrainPop; North Pole (3:37)

2. Revolution a. Earth traveling around the __SUN__ is called __REVOLUTION__ b. __REVOLUTION__ is the movement of one object around another. c. __ONE__ revolution around the Sun is called a __YEAR__ d. The __PATH__ the earth takes as it __REVOLVES__ around the sun is called a __ORBIT__ Earths __ORBIT__ is a slightly elongated circle, called an __ELLIPSE__

3. Calendars b. __EGYPTIANS__ created one of the first __CALENDAR__ a. A __CALENDAR__ is a system of organizing __TIME__ that defines the __BEGINNING__, __LENGTH__, and __Divisions__ of a year b. __EGYPTIANS__ created one of the first __CALENDAR__ c. Early people used __MOON__ cycles to __DIVIDE__ the year. d. One __FULL__ moon to the next is about __29.5__ days e. A year of __12__ of these __MOONTHS__ add up to 354 days f. __ROMANS__ borrowed the Egyptian __CALENDAR__ g. Earth __ORBITS__ the sun in about __354 ¼__ days h. The __1/4__ day is added every __4__ years calling it a __LEAP YEAR__ i. __LEAP YEARS__ keep the __ANNUAL__ events on the same day. BrainPop: Leap Year (4:13)

B. THE SEASONS ON EARTH a. The __4__ distinct seasons are: __WINTER__, __SPRING__, __SUMMER__, and __FALL__ It is __WARMER__ near the __EQUATOR__ than the __POLES__ 1. How Sunlight Hits Earth a. __SUNLIGHT__ hits the earth __DIRECTLY__ at the equator. Near the __POLES__ sunlight is __SLANTED__ b. This is why it is __WARMER__ near the equator than the __POLES__ BrainPop; Seasons (1:58)

2. Earth’s Tilted Axis a. Earth has __SEASONS__ because its axis is __TILTED__ as it revolves around the __SUN__ b. The angle is __23.5__ degrees from the vertical c. __SUMMER__ and __WINTER__ are caused by Earth’s tilt as it __REVOLVES__ around the sun. d. __SEASONS__ is not caused by __EARTH’S__ distance from the __SUN__

3. Earth in June a. The __NORTH__ axis is __TILTED__ towards the sun, which equals __SUMMER__. The south __AXIS__ is tilted __AWAY__ from the sun, which equals __WINTER__ 4. Solstices a. The __SUN__ being furthest from the __EQUATOR__ is called a __SOLSTICE__ b. __SUMMER__ solstice is __JUNE 21st__, the __LONGEST__ day of the year. c. Winter __SOLSTICE__ is __DECEMBER 21st_ , the __SHORTEST__ day of the year.

5. Equinoxes a. When the __SUN__ is directly over the __EQUATOR__ is called a __EQUINOX__ b. Equinox means __EQUAL NIGHTS__ 12 __HOURS__ of day and __12__ hours of night. c. __VERNAL__ (Spring) equinox occurs around __MARCH 21st__, Autumnal __EQUINOX__ occurs around __SEPTEMBER 22nd__ BrainPop: Solstices and Equinoxes (4:44) Chichen Itza (4:00) http://www.youtube.com/watch?v=q0kOyGZxKh4

Ch. 1, Sect 2 P 16 – 19 I. Gravity and Motion A. Gravity a. __GRAVITY__ attracts all objects toward each other. b. __NEWTON’S__ law of universal gravitation states that __EVERY__ object is attracted to every other object. c. The 2 factors that __GRAVITY__ depends on is the __MASS__ of the objects and the __DISTANCE__ between them. BrainPop: Gravity (2:43)

B. Gravity, Mass, and Weight a. __MASS__ is the amount of matter in an object. b. __WEIGHT__ is the force of __GRAVITY__ on the object. C. Gravity and Distance a. The __FORCE__ of gravity __DECREASES__ with the distance between objects.

2. INERTIA and ORBITAL MOTION a. __INERTIA__ is the tendency of an object to resist a change in motion. b. Newton’s 1st law states: An __OBJECT__ at rest will stay at rest and an object in __MOTION__ will stay in motion unless an outside force acts upon it. c. 2 factors keep Earth in orbit: __INERTIA__ and __GRAVITY__ BrainPop: Newton’s Laws of Motion (1:44)