movements of the earth: gravity, inertia, rotation, revolution
TRANSCRIPT
Movements of the Earth: Gravity, Inertia, Rotation, Revolution
GravityGravity 1. Pulling force that attracts
objects2. Pulls things down on Earth
GravityGravity
3. Every object has gravity4. Strength depends on mass & distance between objects
GravityGravity
A space station is to be located between the Earth and the Moon at the place where the Earth’s gravitational pull is equal to the Moon’s gravitational pull. Which of these locations would be best? Explain
GravityWhat does gravity do?
1. Holds planets in paths around sun
GravityWhat does gravity do?
2. Keeps moon in its orbit around the Earth
GravityWhat does gravity do?
3. Keeps entire universe moving in an orderly way
InertiaInertia 1. Every object in universe is
moving
InertiaInertia 2. A body in motion stays in
motion3. A body at rest stays at rest4. Unless acted on by a force
InertiaInertia 5. Every object tries to stay
the way it isEither moving or resting
InertiaWhat does inertia cause in space?
1. Moon to keep moving around Earth2. Planets to keep orbiting the sun
InertiaWhat does inertia cause in space?
3. Galaxies to keep moving through space
EARTHParts of the Earth
1. Equator- horizontal line dividing north and south hemispheres
EARTHParts of the Earth
2. Latitude- horizontal lines3. Longitude- vertical lines
EARTHParts of the Earth
4. Hemispheres- N & S, E & W
EARTHParts of the Earth
5. Earth’s axis is tilted 23.5 degrees
EARTH’S MOVEMENTSEarth’s movements
1. Rotation- spins like a top2. Revolution- moves around sun (30km/sec) in oval path
EARTH’S MOVEMENTSROTATION 1. Earth spins on its axis
2. 24 hours= one rotation3. Causes night and day4. Side of Earth facing sun has day
EARTH’S MOVEMENTSREVOLUTION
1. Earth goes around sun (orbits)2. Takes 1 year = 365 1/4 days3. Causes seasons4. Hemisphere tilted toward sun has summer
EARTH’S REVOLUTIONSEASONS 2. When north hemisphere
is tilted toward sun = summer
More direct, intense light rays, warm Earth more
EARTH’S REVOLUTIONSEASONS 3. When north hemisphere
is tilted away sun = winterWeaker, spread out light rays, warm Earth less
EARTH’S REVOLUTIONSEASONS 4. When n. hemi has winter,
s. hemi has summer
EARTH’S REVOLUTIONSEASONS 5. Spring and Fall occur
when neither hemisphere is tilted toward or away from the sun
Equinoxes
Diagram of Earth’s Seasons