7th grade- earth science- topography

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