ch 29.1-29.4 Flashcards
round, three-dimensional object, the surface of witch is the same distance from the center in all directions
sphere
ellipse
is earth a perfect sphere
The diamiter is wider then pole to pole, No
what are some ancient observations that shows earth is a sphere
and object falls straight down, the earths shadow on the moon is cerved, people on the other side of earth see diferent starts
what are two factors that affect gravitational strganth
masses and distance
what dores the magnetic field portect earth from
harmful radiation from sun
whitch hemishpere is the north megnetic pole located in
northern pole
whatch dergrees does earths axes tillt
11.7degrees
can this evenct magnetic poles change
yes
what is the name of the large scale movement where the magnetic poles swich
magnetic reversal
when does the magnetic poles swich
every 200,000 years
whitch part of the earhs magnetic field deflects harmful radiation from the sun
magnetosphere
what are they two names for the northern and southern lights
Aurors Borealis (northern lights) Aurora Australis ( southern lights)
how are the Auroras created?
electrically-charged particles collide with atomsphere and emit light
when is earth closest and farthest from the sun
eary january- 147 million km
July- 152 millon km
an area 15 dregrees wide in which the time is the same
time zone
the spining of Earth on it’s axis(an imaginaty line drawn from Earth’s north pole to south pole
rotation
motion pf Earth in an elliptical ordit around the sun
revolution
plane of earths obit around the sun
ecliptic
occurs when earht’s rotational axis is tilted directly toward the sun or away from the sun
solstice
earth’s rotational axis is perpendicular to a line drawn from the center of the Earth’ to the center of the sun
equinox
who devised a method of timekeeping around 3000 B.C.?
Babylonians
what was the symbol foe degree taken from?
taken from their symbol for the sun
How many degrees does the earth spin in on day?
360 degrees
How many hours does it take the eath to make one full rotstion?
24 hours (23 hours 56 minutes)
How many degrees does the earth spin in one hour?
15 degrees
What direction does the sun rise?
east
What direction does the sun set?
west
True or False: All time zones are the exact same size?
False they are modigied to fit around cities, states, and country borders, and other key sites
How many time zones are there in the world?
24 time zones
Which direction do you move to add hours to the time?
east
which direction do you move to subtract hours from the time?
west