| Orographic Lift Instructional Objectives
Background Information
Activity
Evaluation
Web Resources
Topic: The Weather of Denali National Park
Instructional
Objectives: Students will:
1. Identify
orographic lift through observation of teacher
demonstration.
2. Record their
observations of orographic lift in student science
journals.
3. Draw their
observations of orographic lift.
4. Identify
orographic lift in the scenes of The Living Edens
"Denali."
Background Information:
Orographic lifting
occurs when elevated terrain's, such as mountains,
act as barriers to the flow of air. As air ascends a
mountain slope, adiabatic cooling often generates
clouds and precipitation. Some of the rainiest places
in the world are located on windward mountain slopes.
In addition to providing the lift to render air
unstable, mountains remove additional moisture in
other ways. Mountains retard the passage of storm
systems. This results in higher precipitation in
mountainous regions.
(Source: Lutgens, Frederick K. and Tarbuch, Edward J., The
Atmosphere: An Introduction to Meteorology, Fifth
Edition, Prentice Hall, Englewood Cliffs, NJ,07632,
1992. p.89)
Activity: Orographic Lift
Time Needed
For Activity: One 45 minute period to
demonstrate the concept of Orographic Lift.
Target Grade Level: Middle school
(Extensions for elementary and
secondary found below.)
Materials
Needed: TEACHER DEMONSTRATION
- One large
cardboard box (.75-1 meter tall) to represent Mt.
Denali
- One smoke bomb available at party stores (12 for
$3)
- Matches
- Room with ventilation or outside
- Small house fan with low speed
- Student science journals
- Porcelain dish in which to place smoke bomb
- Safety glasses for each student
- Folded cardboard insert as found in glassware
boxes to prevent breakage (Use as a baffle/wind
tunnel to direct the flow of air of the small
fan.)
- Conduct activity outside on a calm day
(Extension: A heat source such as a hot plate in
front of the base of the box might create enough
heat to make smoke (storm front) rise more
quickly over the mountain.)
Procedures:
1. Teacher will
set up demonstration outside with box, fan about
two meters away and smoke bomb in porcelain dish
in between fan and box.
2. Teacher will light smoke bomb, turn on fan at
low speed to aim smoke
(using wind tunnel/baffle) at box representing
Mt. Denali.
3. Students will observe the collection of smoke
at the front side of the box and watch smoke rise
up to the top of the box to illustrate Orographic
Lift.
4. Students will observe and record observations
in student science journals.
5. Teacher will dispose of smoke bomb and lead
class discussion as to what Orographic Lift looks
like.
Evaluation/Alternative Assessment:
Students will
present to class what they observed. Students will
also draw pictures illustrating what they observed
and record observations in their student science
journals.
Elementary Extension:
Use cloud
charts available from science supply stores to
determine types of clouds found in the Denali
film. Students may want to draw different kinds
of clouds on blue construction paper using white
or gray chalk.
Secondary
Extension:
Students could
work in teams of three to four and research other
weather patterns found at
Denali. Students will bring the results of the
weather research back to class and present their
findings.
Web Resources on Orographic Lift:
Lifting of Air Masses
http://www.avalanche.ca/weather/glossaries/advanced/advdefs/lifting.html
Rapid City, South Dakota NOAA Office
http://www.crh.noaa.gov/unr/iwe/1972/Weather/
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