Unit 2 Quiz
Prime Meridian
(0 degrees longitude) an imaginary line that runs through Greenwich England and separates the Eastern and Western Hemisphere
Oblate Spheroid
(shape of the earth) bulges very slightly at the equator and flattens very slightly at the poles
How does latitude work?
- (x axis) lines that RUN east and west BUT MEASURE north and south - 0 to 90 degrees north/south -equator divides Northern and Southern Hemisphere -largest great circle of latitude -Earth rotates COUNTERCLOCKWISE (west to east) so sun rises in the east and sets in the west
What is longitude?
- (y-axis) lines that RUN north and south BUT MEASURE degrees east and west of the Prime Meridian
What is the shape of the earth?
-NEARLY a perfect sphere -oblate spheroid
How do we prove the earth is round? -Satellite pictures
-Satellite pictures are the best piece of evidence we have to prove Earth's shape
1 degree latitude/longitude=
-approximately 70 miles -60' minutes
Time zones
-each time zone is 15 degrees apart -Earth rotates 360 degrees in 24 hours (360 degrees/24 hours= 15 degrees/hour) -all places on the same longitude have the same solar noon (sun is highest in the sky)
What proof is there that the earth is slightly oblate?
-gravity measurements. gravity is the force of attraction between any 2 objects. increase mass of objects=increase gravity decrease distances=increase gravity -if Earth were a perfect sphere, it would be expected to exert an equal force on objects at equal distances from the center of Earth
What is a Meridian?
-lines of longitude that separate time zones -they converge (come together) at the poles and diverge (separate) at the equator
How do we describe the Earths surface?
-mostly smooth -even largest mountains are very small compared to the earth
How do we prove the earth is round?-Lunar eclipse
-only a sphere can cast a shadow that appears round. during a Lunar eclipse the Earth casts its shadow on the moon during the full moon phase
Same latitude
-same # of day light hours -similar seasons -same angle of insolation (sun) -same sunrise and sunset
Oblate sphere
-the difference is SMALL -we CAN NOT see it with the naked eye -earth still appears like a sphere -BE CAREFUL ON A MULTIPLE CHOICE ALWAYS PICK THE PERFECT SPHERE
How do we prove the earth is round?-Altitude of Polaris
-this is the star that lies in space directly over the geographic North Pole of the Earth -if you stood at the North Pole, Polaris would be directly overhead -Polaris=to latitude (in Northern Hemisphere) -increase latitude, increase the altitude of Polaris
How can we calculate how round the Earth is?
-use roundness ratio -a perfect sphere had a roundness ratio to 1 -rr= polar diameter/equatorial diameter -example) Earth rr= 12,714 km/12,756km
Weight—-> Meausre of gravitational force
-we are further from the from the center of the Earth at the equator- gravity is less -this means we weigh less -we are closer to the the poles so we weigh more
What is the roundness ratio of a perfect sphere?
1
How do we prove the earth is round?
1) Satellite pictures 2) Sinks ship 3) Lunar eclipse 4) Altitude of Polaris 5) Gravity
Earths polar diameter
12,714 km
Earths equatorial diameter
12,756 km
What is the highest degree of longitude?
180 degrees - range 0 to 180 W/E
What is the international date line?
180 degrees longitude -separates one day from the next -longitude lines are separated 15 degrees apart
What is the highest degree of latitude?
90 degrees - range is 0 (doesn't have N/S) to 90
lines of latitude
ARE PARALLEL
What are the layers of the Earth? Outer core
Believed to be liquid iron- because seismic (S or earthquake) waves can't pass through. responsible for magnetism of Earth
What are the layers of the earth? -Crust
Continental crust (thick and less dense) Oceanic crust (thinner and more dense) -30% of earths surface
What is longitude and latitude?
Imaginary lines on a map used as earth's coordinate system
As latitude increases, what happens to the altitude of Polaris?
It increases
Troposphere
Mostly nitrogen gas (78%) and oxygen gas (21%). some water vapor
What are the layers of the earth?- Hydrosphere
Oceans, lakes, rivers, etc. -70% of earths surface
Stratosphere
Ozone (03)- protects us from UV radiation
Object that best represents a true scale model of the shape of earth
Ping pong ball
Plastic mantle or asthenosphere
Putty like properties. Hot rocks that can flow (convection currents)
Why do Meridian lines zig zag over populated areas?
So populated areas aren't separated by two different time zones
What are the layers of the Earth?-Inner core
Solid iron and nickel Most pressure and density Meteor evidence
Stiffer mantle
Solid rock
What are the layers of the earth? -Atmosphere
Sub divisons: -Thermosphere -Metosphere -Stratosphere -Troposphere -Temp begins to change at each "pause" when altitude increases= pressure decreases and density decreases
What are the layers of the Earth? -Mantle
Sub divisons: -rigid mantle -plastic mantle or asthenosphere -stiffer mantle -crust and rigid mantle combine to form the lithosphere-brittle outer shell of rock surrounding Earth
Why do the stars around Polaris appear to move?
The Earth rotates on its axis
What causes oblateness?
The earths rotation
What best explains the apparent sinking of sailboats?
The sailboat is moving around the curves surface of the Earth
What is evidence that the Earth rotates on it's axis?
The stars appear to follow daily circular paths around Polaris
Rigid mantle
Very similar to oceanic crust
Solar noon occurs
When the sun is at its highest altitude
The angle of the star Polaris above the northern horizon can be used to determine an observers
latitude
Compared to the weight of a person at the North Pole, the weight of the same person at the Equator would be
slightly less, because the person is farther from the center of Earth
Zenith
the highest point in the sky (90 degrees north)
