Unit 3: Earth’s Dimensions

I get around the topography with no problem dude!!! …

P.S. I’m Rocky

The Earth’s Four Spheres

GeosphereAtmosphereHydrosphereBiosphere

GeosphereSolid EarthAll interior layers of the Earth, from the surface to the core.

AtmosphereGaseous envelope surrounding the Earth.

HydrosphereAll liquid and solid water on the Earth.

OceansLakes RiversGroundwater…and Polar and high altitude ice caps.Approximately 70% of the Earth’s surface is covered with water. Only 3% of that water is

fresh water.

BiosphereAll forms of life

Single celled protozoans to plant life to people.

Interactions Among The Spheres

The Spheres of Earth!Put these in order of increasing density:

AsthenosphereHydrosphereLithosphereGeosphere

What is the best map of the earth’s surface?

A globeBest model of earth’s shape= ping pong ball!

Latitude and Longitude

How do we communicate an exact location on earth’s surface to another person?

What information do you need to locate a point on the

earth’s surface?

You need a coordinate system!

Coordinate SystemA system or group of defined imaginary lines forming a grid used for the determination or location of a point on the surface of an object.Two intersecting lines are needed to locate a point on a 2d surface.latitude/longitude system used to determine exact locations on the surface of the Earth

Latitude and Longitude

How can positions on a sphere be located?

LatitudeAngular distance north or south of the equator, measured from the center of the earth [the core].They are Horizontal Lines running east-west, but, measure north-south.Measured in degrees, minutes, and second.

• Latitude» rungs

of a ladder

Latitude

Like climbing a ladder, N is up the ladder S is downThe equator is 0 degrees and the poles are at 90 degrees.

Latitude– Latitude lines are parallel to each other

and are therefore also called parallels– Lines get shorter in length as you move

away from the equator– if you drive east or west along a line of

latitude, the altitude of Polaris remains the same

– Recall the Altitude of Polaris equals the latitude of the observer

                                                                                                                                                   

Longitude

Angular distance east or west of the prime meridian, measured from the center of the earth [the core].Vertical Lines running north-south through the poles, but, measure east-west.180° east or west or the prime meridian is the largest longitude there isThe prime meridian is 0 degrees and the International Date Line is 180 degrees.

Longitude

• Longitude– orange

peels– the long

way

Longitude• Lines of Longitude (Meridian)

– lines are not parallel– lines meet at the poles– Also called meridians– Lines are all of equal length– As you travel N & S along a Meridian

your time stays the same– Each degree is divided into 60 equal

parts called minutes.– Each minute of a degree is divided

into 60 equal parts called seconds.

                                                                                                                                                   

Equator

An imaginary horizontal line circling the Earth halfway between the north and south poles. It is areference line for latitude.0° latitude

Prime Meridian

Imaginary vertical line from the N pole to S pole that passes through Greenwich EnglandReference line for longitude0° Longitude on the Earth.

Other Reference PointsNorth Pole – The point at 90° North of the equator. Very top of earthSouth Pole – The point 90° South of the equator. Very bottom of earth

International Date Line180° East or West of the Prime MeridianOn the direct opposite side of the earth from the prime meridian.The Prime Meridian and the International Date form a vertical circle that cuts the earth in ½ vertically

East of the International Date Line is a day earlier with the same time. West of the International Date Line is a day later with the same time

Time ZonesThe Earth rotates from west to east at a rate of 15°/hour.Time zones are divided up by 1hour/15°Travel to the west and the time gets earlier and travel to the east and the time gets later.

Time Zones

0o 30

o

60o

90o

180o

150o

120o

30o

60o

90o

180o

150o

120o

(GMT) EastWest

Noon+ New Day

102 4 6 82 4 6 8 10

- New Day

AM PM

If it is 3:00 PM for a person located on the tip of India, what time is it for people in the following locations?

New York:______________Alaska:________Florida: _________________Italy:___________________California: ________________

5 AM11 AM

5 AM

2 AM

12 AM

Topographic Maps!

Earths Fields and Field Maps

What is a field?What is a field map?

Describing Earth’s Fields

Field – a region which contains measurable quantities at every location. (i.e. elevation, temperature, pressure…)Field Value – the value of what is being measured. (i.e. temperature, elevation, pollution concentrations…)Magnitude – Value for a point on a field.

Field Values (cont.)

Scalar Field – A field described in terms of magnitude alone (i.e. temp., pressure, humidity)

Vector Field – A field described with both magnitude and direction (i.e. wind velocity, gravity, magnetic fields)

IsolinesA line on a field map that connects all points of equal value.

Note: ES0304

Types of Isolines

Contour Line – Isoline that connects points of equal elevations on a contour map.Isotherm - Isoline that connects points of equal temperature on a field map.Isobar – Isoline that connects points of equal pressure on a field map.

Isosurface

A surface in a field that has the same field value throughout.

Important Field Map Terms

Topographic map/Contour map – A map that uses contour lines to show elevation and landforms.Elevation – Height above mean (average) sea level.Contour interval – Vertical distance, or change in elevation, between adjacent or consecutive contour lines.

ScaleThe ratio of a model to the object. (i.e. globe to earth)Use the scale on the map as the ruler to measure that map.

Angle of Declinationor Magnetic Declination

The angle between true north (geographic north, north pole) and magnetic north.

The angle of declination varies depending on your position on the earth.

General Contour Map Rules

Rule of ‘V’s – as contour lines cross a stream they bend uphill.

The steeper the slope the closer the lines are to each other.

CONTOUR LINES BEND WHEN CROSS STREAMS

UPSIDE DOWN V’S POINT UPSTREAM STREAMS FLOW DOWN

CLOSER CONTOUR LINES = STEEPER GRADIENT

TOPOGRAPHIC MAPS WOULD BE VERY CLUTTERED IF ALL CONTOUR LINES WERE LABELED, SO ONLY HEAVIER LINES called an index contour SHOW LABELS

Rules for Drawing Isolines:

1. Isolines connect points of equal value.

15

5 5

1510

1010

10

2. Isolines are gentle, curving lines- no sharp corners.

15

5 5

1510

1010

10

3. Isolines are always closed curves even though the map might only show part of it.

4. Isolines NEVER cross- this would mean that one point has two different values. Ex: one spot has two temperatures?

20°

30 °

40 ° 50 ° 60 °

X

YZ

5. Isolines usually are parallel. (They have a parallel trend.)

Visualizations of contour lines

http://geology.asu.edu/~sreynolds/topo_gallery/topo_gallery.htm

Tips on Drawing Contour Lines• Always draw a contour line so that elevation reading is higher

on one side of the contour line and lower on the other side.

• Assume a steady elevation change between neighboring readings when positioning contour lines.

• Adjacent contour lines tend to look alike.

• Continue drawing a contour line until it reaches the boundary of plotted data or “closes” to form a loop by making its way to its starting point.

• Contour lines never stop or end within a data field, and they never fork, touch or cross one another.

• Contour lines cannot skip values and must always appear in sequence.

• Only draw contour lines that fall within the range of data reported on the map.

• Always label all contour lines.

Draw Isolines Connection equal values of elevation

80

100

80120

90

100

120

110

90

9090

100

90

90

120

90 90

70

112

90

80

90

808080

80

80

Elevations in meters above sea level

Note: ES0304

Highlight data points.

Fill in gaps in data.

Connect the dots.

Go on to the next value.

Making a Contour Map II

Drawing Contour Maps III

Gradient –a measure of how a field value changes with distance.

Gradient = Change in field value Distance

100m 10m

10km

100m – 10m

10km= =

90m 10km

= 9m/km

GradientGradient shows how quickly the value changes from one point to another.

Gradientvalue

dis ce=

Δtan

A steep (high) gradient changes quickly and the isolines are close together.A gentle (low) gradient changes slowly and the lines are far apart.

Steep area

Gentle area

1km=1cm

Steep area

Gentle area

1km=1cm

Calculate the gradient of the slope along the line drawn in the diagram. Assume that elevations are given in feet. Show work including formula below:

Making Contours worksheets

Worksheets can be printed from:http://www.rcmurphy.net/Medina%202005/documents/Contours123.doc

What is the pattern of the contour lines around a simple hill?

Concentric circles getting smaller - hill

Identify the features marked at A and B

Hachure contour lines (lines with tick marks) show depressions – the first hachure is equal to the last contour line passed

20 2010

WHAT DOES THIS PROFILE SHOW?

VOLCANO

NOTICE HACHURE DEPRESSION LINES IN CENTER SHOWING VOLCANIC VENT

ProfilesProfile – a side view of an area showing elevation.

TOPOGRAPHIC PROFILES

TOPOGRAPHIC MAPS SHOW THE ELEVATION OR VERTICAL DISTANCE ABOVE SEA LEVEL OF THE SURFACE OF THE EARTH

TOPOGRAPHIC PROFILE IS A SIDE VIEW OF AN AREA CUT ALONG A PARTICULAR LINE.

So, if we were to look at a profile view of line AB on our topographic map, what might we expect to see? Predictions?

Time to FIND OUT!

Step 2

Make the X-axis exactly as long as line AB.

Next, decide what the HIGHEST and LOWEST elevation values are that line AB crosses on your topographic map and create a scale. You may wish to increase your scale by the contour interval on the map to make things easier. In this case, we are going up by 10’s, because our contour interval on the map is 10 meters.

Hold your scrap paper page up to the profile.

Transfer the tick marks directly onto the profile.

This is what you might expect the “profile” or cross section view of line AB to look like! Notice how the line dips below 250m where it crosses Long Creek

Does it make sense? SURE! There is a creek flowing through this region. Think about where it would flow on your profile. We also recognize the V shaped contour lines that indicate the direction of water flow.

The contour lines point up the page (orange), but Long Creek flows down the page.

Contour lines point upstream. Stream flows from high elevation to low elevation. So a stream flows in the opposite direction the contours point.

Or… if you are lucky enough to be able to do your profile on the same page as the topographic map…

You can use the: “Drop down a dotted line”

method!

Same idea, but no need for tick marks and scrap paper!