Earth Science CK-12 Chapter 2 *updated
Principles that are important for reading a topographic map: 5. What are three common scales used in USGS maps?
(1) 1:24,000 scale -1 inch = 2000 ft (2) 1:100,000 scale -1 inch = 1.6 miles (3) 1:250,000 scale -1 inch = 4 miles
What are the two steps you would do to calculate the contour interval in a contour map?
1. Calculate the difference in elevation between two bold lines 2. Divide that difference by the number of contour lines between them
Principles that are important for reading a topographic map: 4. Where water flow is light or nonexistent, there is no longer what?
A blue line
Mathematically, a contour line is a curve in two dimensions on which the value of a function f(x,y) is a what?
A constant
Principles that are important for reading a topographic map: 3. Hatched concentric circles indicate what?
A depression
Principles that are important for reading a topographic map: 2. Concentric circles indicate what?
A hill
Principles that are important for reading a topographic map: 2. When contour lines form closed loops all together in the same area, this would be what?
A hill
On a topographic map, contour lines create a group of concentric, closed loops. What feature could this indicate?
A hilltop
Principles that are important for reading a topographic map: 2. Broadly spaced contour lines indicate what?
A shallow slope
Principles that are important for reading a topographic map: 1. Contour lines that seem to indicate what?
A very steep slope, like a cliff or canyon wall
In a contour map, each contour line represents a specific elevation and connects all the points that are at where?
At the same elevation
A topographic map with the contour lines representing deph below sea level, rather than height above
Barthymetric maps
Principles that are important for reading a topographic map: 1. Closely-spaced contour lines indicate a steep slope, why?
Because the elevation changes quickly in a small area
Principles that are important for reading a topographic map: 4. If a stream contains water, the contour line will be
Blue
In a contour map, every fifth contour line is what?
Bolded and labeled with numerical elevations
In a contour map, a single point can only have what?
Can only have one elevation
Topographic maps use what to show different elevations on a map?
Contour lines
Type of isoline; in relation topographic maps, a line of equal elevation
Contour lines
Mapping is a crucial part of what?
Earth science
A map that shows the geological features of a region
Geologic map
Principles that are important for reading a topographic map: 3. Outer hatched circles of hatched concentric circles represent what?
Higher elevations
Principles that are important for reading a topographic map: 5. Scales on topographic maps indicate what?
Horizontal distance
On a topographic map, five contours lines are very close together in one area . The contour interval is 100 ft. What feature does that indicate? How high is this feature?
If the contour interval is 100 ft that means that there is 100 ft in between each line so that would mean it would be very steep and it would be 400 ft high.
On a topographic map, six contour lines span a horizontial map distance of 0.5 inches. The horizontal scale is 1 inch equals 2,000 ft. How far apart are the first and sixth lines?
If the distance between the first and sixth line is 0.5 inches which equals 1,000 feet and 1 inch is equal to 2,000 feet and there are six lines then there is 1,000 feet inbetween the first and sixth line.
In a contour map, two contour lines next to one another are separated by a constant difference in what?
In elevation
Bathymetric maps help oceanographers visualize what?
Landforms at the bottoms of lake, bays, and the ocean as if the water were removed
In a contour map, the contour lines run next to each other and NEVER what?
Never cross
In bathymetric maps, number are what and become what?
Numbers are low near sea level and become higher with depth
Principles that are important for reading a topographic map: 1. Contour lines show the 3D shape of what?
Of the land
On a geologic map of the Grand Canyon, a rock unit called the Kaibab Limestone takes up the entire surface of the region . Down some steep topographic lines is a very thin rock called the Toroweap Formation and down more topographic lines into the canyon from what that is another thin unit, the Coconino Sandstone. Describe how these three rock units sit relative to each other. Which is oldest and which is youngest?
On the top is the Kaibab limestone, next is the Toroweap Formation, and after that is Coconino sandstone. The oldest is the Coconino sandstone and the youngest is the Kaibab limestone.
What two things are shown in geologic maps?
Rock units and geologic structures
In a geologic map, rock units are what?
Rock units are color-coded and identified in a key
Principles that are important for reading a topographic map: 3. Hatch marks of hatched concentric circles are what inside a circle?
Short perpendicular lines
Principles that are important for reading a topographic map: 4. V-shaped expanses of contour lines indicate what?
Stream valleys
In a geologic map, structural features such as what are shown?
Structural features such as folds and faults
With contour lines to indicate elevation, topographic maps show what?
Terrain
Principles that are important for reading a topographic map: 4. Where water flow is light or nonexistent, there will no longer be a blue line, but contour lines that point uphill indicate what?
That the stream channel is still there
In a contour map, what does the map legend give?
The countour interval
The constant difference in elevation that seperates two contour lines next to one another in a contour map
The countour interval
Principles that are important for reading a topographic map: 3. Innermost hatched circle of hatched concentric circles would represent what?
The deepest part of a depression
Principles that are important for reading a topographic map: 4. If a stream contains water, and the contour line is not blue, the V patterns indicate what?
The direction water will flow
Principles that are important for reading a topographic map: 4. The channel of a stream passes through a point of the V and the open end of the V represents the what?
The downstream portion
Principles that are important for reading a topographic map: 2. The smallest loops of contour lines are what?
The higher elevations of a hill (uphill)
Contour lines connect all the points on a map that have the same elevation and therefore reveals what?
The location of hills, mountains, and valleys
Principles that are important for reading a topographic map: 2. The larger loops of contour lines are what?
The lower elevations of a hill (downhill)
On a topographic map, a river is shown from Point A in the northwest to Point B in the southeast. Point A is on a contour line of 800 ft and Point B is on a contour line of 900 ft. In which direction does the river flow?
The river flows toward point A, so northwest.
Principles that are important for reading a topographic map: 5. The horizontal scale on topographic maps can be used to calculate what?
The slope of the land (vertical height/horizontal distance)
Describe the pattern on a topographic map that would indicate a stream valley. How do you determine the direction of water flow?
There would be a striaight line with some Vs going through it, the lines that extend the Vs outward show that the river is going in the same direction.
Maps are extremely useful to Earth scienctists to represent and show what?
To represent geographic features found above and below sea level and to show the geology of a region
Represents the location of geological features, such as hills and valleys
Topographic maps
Principles that are important for reading a topographic map: 4. Where a stream crosses the land, the Vs in the contour lines point where?
Uphill
If you walk along a contour line you will not go where?
Uphill or downhill
On a topographic map, describe how you can tell a steep slope from a shallow slope.
When it is a steep slope the lines are very close together, when the lines are father away from each other it is a shallow slope.
While a road map shows where a road goes, a topographic shows what?
Why
echo sounder
a device that uses sound waves to calculate distances to underwater objects and the seafloor
plate
a slab of lithosphere that can move over the Earth's surface
continental drift
an early 20th-century hypothesis that the continents move over Earth's surface
convection cell
circular current of warm material rising and cool material sinking that transfers heat
trench
deep crack in the ocean floor
core
dense, metallic center of Earth, consisting of the inner and outer core
seismic wave
earthquake wave that transports energy from an earthquake through the ground in all directions
seafloor spreading
hypothesis explaining how the ocean floor forms and how continents can drift
island arc
line of island volcanoes resulting from subduction of one oceanic plate beneath another oceanic plate
convergent plate boundary
location where two lithospheric plates come together
plate boundary
location where two lithospheric plates meet
divergent plate boundary
location where two lithospheric plates move apart
transform plate boundary
location where two lithospheric plates slide past one another in opposite directions
meteorite
metallic object from the early solar system that strikes Earth's surface from space
mantle
middle layer of Earth, consisting of hot, solid rock
asthenosphere
part of the upper mantle below that lithosphere that can flow and bend
lithosphere
rigid part of Earth that consists of the crust and upper mantle, lying above the asthenosphere
magnetic field
the area surrounding a magnet over which it exerts a magnetic force
subduction zone
the area where two lithospheric plates come together, which one sinks beneath the other
subduction
the sinking of one lithospheric plate beneath another
continental rifting
the splitting of a continent at a divergent plate boundary
plate tectonics
theory that Earth's lithosphere is divided into plates that move over the asthenosphere
plate tectonics
theory that Earth's surface is divided into lithospheric plates that move over the planet's surface
continental crust
thicker, denser part of Earth's crust that makes up the continents
crust
thin, brittle outer shell of Earth, consisting of continental and oceanic crust
oceanic crust
thinner, less dense part of Earth's crust that makes up the ocean basins