Ch 29 Flashcards
A round, three-dimensional object, the surface of which is the same distance from the center in all directions
Sphere
An elongated, closed curve with two foci
Ellipse
Is it Earth a perfect sphere?
No, the diameter around the Equator is longer than the diameter from Pole to Pole
What are some ancient observations that proves Earth is a sphere?
Any object that falls, falls straight down, the Earth’s shadow on the Moon during the Lunar Eclipse is curved, and people in different parts of the Earth see different stars above their horizons
What are two factors that affect gravitational strength?
Mass of object and Distance between them
Which one of Earth’s diameter is longer, pole to pole, or Equator?
Equator
What does the magnetic field protect Earth from?
Harmful Radiation from the Sun
Which hemisphere is the South Magnetic Pole located in?
The Northern Hemisphere
At what degrees, does Earth’s axis tilt?
11.7 Degrees
Can the Magnetic Poles change?
Yes
What is the name of the large-scale movement, where the magnetic poles switch?
Magnetic Reversals
How often do Magnetic Reversals occur?
Every 200,000 Years
Which part of Earth’s Magnetic Field, deflects harmful radiation from the Sun
Magnetosphere
What are the two scientific names for the Southern Lights and Northern Lights?
Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights)
How are the Auroras created?
Electrically charged particles in the Sun collide with atoms in the atmosphere and emit light
When is Earth closest to the Sun?
Early January- 147 Million km
When is Earth farthest to the Sun?
Early July- 152 Million km
An area 15 degrees wide in which the time is the same
Time Zone
The spinning of Earth on its axis, an imaginary line drawn from Earth’s North Pole to its South Pole
Rotation
The motion of Earth in an elliptical orbit around the Sun
Revolution
The plane of Earth’s orbit around the Sun
Ecliptic
Occurrence when Earth’s rotational axis is tilted directly toward the Sun or away from the Sun
Solstice
Occurrence when Earth’s rotational axis is perpendicular to a line drawn from the center of the Sun
Equinox
Who devised a method of timekeeping around 3000 B.C?
Babylonians
What was the symbol for degree taken from?
The Sun
How many degrees does the earth spin in one day?
360 Degrees
How many hours does it take the earth to make one full rotation?
24 Hours
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 modified to fit around cities, states, and country borders, and other key sites
How many time zones are there in the world?
24