Chapter 29 Flashcards
What is a sphere ?
A round, three - dimensional object, the surface of which is the same distance from the center in all directions.
What is a ellipse ?
Is an elongated, closed two foci
How can you tell that the Earth is a sphere ?
- People in different places see different stars
- Earth’s shadow on the moon during lunar eclipse is always curved
- Objects fall straight down to the surface as if they are falling toward the center of a sphere
What are two factors that affect the gravitational pull ?
Mass and distance of an object
What is the longest distance of Earth ? Pole to Pole or the Equator ?
26 miles
What does the magnetic field protect Earth from ?
Harmful Solar Radiation
Which magnetic pole is located in the Northern Hemisphere ?
South Magnetic Pole
Which magnetic pole is located in the Southern Hemisphere ?
Northern Hemisphere
At what degrees is Earth’s axis tilted ?
11.7 degrees
Can magnetic poles flip - flop ?
Yes
What are the large - scale movements called when the magnetic poles flip ?
Magnetic Reversals
How often do magnetic reversals occur ?
200,000 years
When did the last magnetic reversal happen ?
780,000 years ago
Within Earth’s magnetic field what reflects solar radiation ?
Magnetosphere
What are the scientific names for the Northern and Southern lights ?
Aurora Borealis and the Aurora Australis
How are the auroras created ?
Electrically - charged particles collide with atoms in the atmosphere and emit light
Which month is Earth closest to the sun ?
January
When is the Earth the farthest away from the sun ?
July
What is a time zone ?
An area 15 degrees wide in which the time is the same
What is a rotation ?
The spinning of Earth on its axis
What is a revolution ?
The motion of Earth in an elliptical orbit around the sun
What is the ecliptic ?
The plane of Earth’s orbit around the Sun
What is a solstice ?
Occurs when Earth’s rotational axis is tilted directly toward the Sun or away from the Sun
What is an equinox ?
When Earth’s rotational axis is perpendicular to a line drawn from the center of Earth to the center of the Sun
Who devised a method of timekeeping around 3000 B.C. ?
The Babylonians
What was the symbol for degree taken from ?
The symbol for degrees was taken from the Babylonian symbol for 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 all modified to fit around cities,states, and country borders, and other key sites.
How many time zones are there in the world ?
24 zones