# 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
 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.
5
5
10
10
10
10
15
15
 2. Isolines are gentle, curving lines-
no sharp corners.
5
5
10
10
10
10
15
15
 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
 Gradient shows how quickly the value
changes from one point to another.
Use your ESRT to write the equation
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

14 cards

21 cards

30 cards

16 cards

30 cards