7th grade- earth science- topography
DESCRIPTION
7th grade Earth scienceTRANSCRIPT
Earth Science
Chapter 1-2, 1-3 & 1-4For last half of March and until the 3rd week in April
only due till a week and half of spring break
The Earth SystemEarth System:
4 main parts 1. Atmosphere 2. Hydrosphere 3. Lithosphere 4. Biosphere
Atmosphere
• The layer of gases that surround and form an envelope around the Earth.– Consists of several gases
• Nitrogen – 78%• Oxygen – 21%• CO2, H2O, others – 1%
Lithosphere• Earth's solid, rocky outer layer
– The continents, islands and ocean floors
Hydrosphere• All of the water present on the planet
– Oceans, lakes, streams, ice caps, snow, glaciers, etc.
Biosphere• That area of the land, water and air that
contains life!
The Earth’s Surface• Topography:
The shape of the land. The topography of an area includes the area's elevation, relief, and landforms.
Elevation - Relief• Elevation -height above sea level• Relief - difference between the highest and the
lowest points of an area
Landforms• 3 main types: plains, mountains & plateaus.
Plains: made up of flat or gently rolling land with low relief
Mountains: made up of high elevation and high relief.
Plateaus: high elevation and a more or less level surface
Earth’s Grid – Equator & Prime Meridian
Prime Meridian goes thru Greenwich, England
Equator is half way between the north & south pole
Latitude & Longitude• Latitude: the distance north or south of the equator• Longitude: the distance east or west of the prime meridian
Both latitude & longitude are measured in
degrees
Latitude & Longitude
Do Now:
When would knowing your altitude be important?
3/18/15SWBAT:
Interpreting a Topographic Map
Isoline -
Is a general term used to describe lines that connect points of equal value on a
map.
** Important Vocabulary **
Types of Isolines -
Isobars - Lines connecting
equal pressures
Isotherms - Lines
connecting equal
temperatures
Contour Lines -
Lines connecting
equal elevations
Index Contour Line
Heavy lines spaced at a predetermined labeled elevations on
a topographic map.
Index Contour
Contour Interval
- The vertical distance that separates EVERY contour line on
a topographic map.
Benchmark – tells the real elevation at that
point
What is the contour interval of this
map?
Estimating Elevation • Label the contour lines based on the map interval
• Find the contour line before and after the point you are trying to determine
• You’re answer should be a point in between those lines
Contour Interval = 10 m
10
. a
20
30
. b . c
Give a possible elevation for
point “a”
Give a possible elevation for
point “b”
What is the highest possible elevation of point “c”?
The highest possible point on a contour map will always be one unit less than the next
possible contour line.
Contour Interval = 10 m
10
. a
20
30
. b . c
Give the HIGHEST possible elevation
for point “c”
What about the LOWEST possible point?
The lowest possible point on a contour map will always be one unit more than the lower
contour line.
Contour Interval = 10 m
10
. a
20
30
. b . c
Give the LOWEST possible elevation
for point “c”
Where would it be easier to hike?
Why? A.
B.
B has a gentle slope, or gradient.
Do Now:
Today’s Objective: 3/26/15
How can a Topographic Profile be Constructed?
There is a mistake on this
topographic map. Identify the mistake and
explain why it is wrong.
Closer contour lines = steep slopes.
Further contour lines = gradual slopes.
Gradient• Refers to the steepness of the land (slope)
Which side of the hill is the steepest?
WHY?N
Contour lines will either
• Run off the map or
• Close on themselves to create circles
Contour lines will NEVER cross.
If contour lines touch they represent a very steep gradient, otherwise called a cliff.
Closed contours with hachure marks represent depressions (holes).
Hachure Contours
The contour line with the marks, or hachures , has the same elevation as the
line before it.
Same Elevation50 Meters
upstream
downstream
When a river or stream crosses a contour line, the contour line bends and points upstream.
River and Streams
• Upstream is where the river starts, higher elevation.
• Downstream is where the river ends, lower elevation.
1. What is the contour interval?
2. What compass direction is Eagle Mt. located?
3. What is the elevation at the edge of Wolf Pond?
4. What is the elevation of Point B? Point C? Point E?
5. Place an “X” on the map where the steepest location would be.
6. What direction is the stream flowing? Explain how your know.
Do Now-What is the contour interval of
this map?
3/26/15
SWBAT- Draw a topographic profile
If given the contour interval, can you label the lines?
View of island from the side.
This would be the topographic profile of
the island.
View of island from above.
This would be the topographic map of
the island.
Contour Profile
- The shape you would see if the land were sliced vertically along a line between two points on a
topographic map
How to draw a topographic profile…
First you need
A map,
Scrap paper
&
A graph
Scr
ap p
aper
Step 1 – Line your
scrap paper up to the
correct line on the map.
Scrap paper
Step 2 – On your
scrap paper, mark off
where all the contour lines
meet the paper
Scrap paper
Step 3 – Label each
tick mark on your scrap paper with the correct elevation
from the map
Scrap paper
0123456666543210
Step 4 – Move your
scrap paper to the bottom of the graph
Step 5 – Go straight up from the
first tick mark and
place a dot on the graph
at the appropriate
height.
Step 6 – Repeat for each tick
mark
Step 7 – Connect each
dot with a smooth line
Let’s try one more time . . .
Do Now:
Today’s Objective:
Calculating Gradient
1. What is the contour interval?
2. What is the elevation of point B?
3. What direction is the creek flowing?
Gradient (or slope)-The rate of change in values between two points on a field
map.
- How gentle or steep the land is
Steep slope – lines are closer
together
Gentle slope – lines are farther
apart
SteepGentle