Earth Science: Unit 1
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Transcript Earth Science: Unit 1
Fields and Isolines !!!!
We’re going to learn about Isolines…isn’t that
awesome???
Whatever, just be quiet and learn.
Fields – WRITE THIS DOWN in
your notes sheet!!
Field – a region of space in which there is a
MEASUREABLE quantity of a given property at every
point
Examples: Temperature, Pressure, Elevation, etc.
The strength of a field varies (Ex. Whoever smelt it..)
The farther away from the source, the weaker the field
Fields can be MAPPED by placing measurements on
paper and connecting locations with EQUAL readings
with figures called ISOLINES!!!
Isolines
What the heck IS an isoline, anyway?
An isoline is a line connecting points of equal value.
Examples of isolines:
Isotherms:
points of equal temperature
Isobar:
points of equal barometric (air) pressure
Contour:
points of equal altitude
Concentration of chemicals
Anything else you can get a value for.
(The weather channel loves isolines!)
Rules for drawing them!
How do you do it?
Here’s how!! Once you learn this, you’ll be experts.
1. Isolines connect points of equal
value.
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10
15
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2. Isolines are gentle, curving lines-
no sharp corners.
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5
10
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10
15
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3. Isolines should always form closed
curves (loops) even though the map might
only show part of it.
So, at times you may have to extend a line
to the edge of the map!
4. Isolines NEVER cross- this would
mean that one point has two different
values. Ex: one spot has two
temperatures?
That’s whack!
40 °
50 °
30 °
60 °
X
20°
Y
Z
5. Isolines usually are parallel. (They
have a parallel trend, and usually follow
the same pattern.)
More on Isolines!!
6) Isolines are drawn according to a designated isoline
interval
On a map, they are called the CONTOUR INTERVAL
7) Isolines should ALWAYS be drawn in pencil
It’s easy to make mistakes, so you might have to do
some heavy duty erasing.
Stop whining.
Visualizations of contour lines
http://geology.asu.edu/~sreynolds/topo_gallery/topo_
gallery.htm
What is Gradient?
Gradient shows how quickly the value
changes from one point to another.
Use your ESRT to write the equation
For Gradient on your notes sheet!
Anything else you should know?
Actually, yes.
You see…sometimes isolines are REALLY close
together
Other times, they are kind of far apart
Does this mean something?
You bet!
How can you tell whether a gradient is steep or
gentle?
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
OK Let’s practice.
We are going to do some isoline practice now
Take out that isoline packet I handed out at the
beginning of the period.
Hurry!
Ok, here we go.
Highlight
data
points.
Fill in
gaps in
data.
Connect
the dots.
Go on
to the
next
value.
Drawing Isolines II
Drawing Isolines III