Teacher Guide: Weather Maps
Learning Objectives
Students will …
 Interpret a weather station symbol.
 Measure the air pressure in high- and low-pressure systems.
 Draw the circulation of air around high- and low-pressure systems.
 Describe typical weather patterns associated with high- and low-pressure systems.
 Compare and contrast cold fronts and warm fronts.
 Explain how the weather might change as a cold or warm front passes through.
Vocabulary
air mass, air pressure, cold front, high-pressure system, knot, low-pressure system,
precipitation, warm front
Lesson Overview
Nearly everyone has listened to a weather person forecasting
tomorrow’s weather. And nearly everyone has grumbled when
that forecast turned out to be wrong. What goes into a weather
forecast?
With the Weather Maps Gizmo™, students will gather
meteorological data and observe typical weather patterns that
are associated with high-pressure systems, low-pressure
systems, cold fronts, and warm fronts. Based on the patterns
they see, students will be able to predict what the weather will
be like as one of these systems passes through.
The Student Exploration sheet contains three activities:

Activity A – Students observe and describe high-pressure systems.

Activity B – Students observe and describe low-pressure systems.

Activity C – Students investigate cold fronts and warm fronts.
Suggested Lesson Sequence
1. Pre-Gizmo activity
( variable)
In the weeks leading up to your weather unit, take the class outside on days when
particular weather systems are present. Have students observe the weather when a
high-pressure system is present and when a low-pressure system is present. If possible,
try to make observations as a cold front and a warm front pass through. Summarize
each set of observations on butcher paper and post them on the wall of your classroom.
When students begin the Weather Maps Gizmo, you can refer to these observations to
see how well they agree with what is shown in the Gizmo.
2. Prior to using the Gizmo
( 10 – 15 minutes)
Before students are at the computers, pass out the Student Exploration sheets and ask
students to complete the Prior Knowledge Questions. Discuss student answers as a
class, but do not provide correct answers at this point. Afterwards, if possible, use a
projector to introduce the Gizmo and demonstrate its basic operations. Demonstrate how
to take a screenshot and paste the image into a blank document.
3. Gizmo activities
( 15 – 20 minutes per activity)
Assign students to computers. Students can work individually or in small groups. Ask
students to work through the activities in the Student Exploration using the Gizmo.
Alternatively, you can use a projector and do the Exploration as a teacher-led activity.
4. Discussion questions
( 15 – 30 minutes)
As students are working or just after they are done, discuss the following questions:

Why are high-pressure systems associated with dry and sunny weather? [Dry air
has relatively high density and tends to sink, forming a zone of sinking air and
high pressure.]

Why are low-pressure systems associated with moist air? [Moist air has low
density and tends to rise, forming a zone of rising air and low pressure.]

Why does air tend to circulate in a clockwise direction around a high-pressure
system, and in a counterclockwise direction around a low-pressure system? [See
the Scientific Background below.]

What causes clouds to form? Based on this, why do clouds often form along
fronts? [Clouds form when moist air rises and cools. This often occurs along
fronts where warm air rises above cooler air.]
5. Follow-up activity: Interpreting weather data
( 20 – 40 minutes)
Have students practice interpreting meteorological data by projecting the Weather Maps
Gizmo to the front of the classroom. Turn off the Show fronts and high/low pressure
areas and Show additional display options checkboxes. Click New, and ask student
volunteers to try to identify weather systems using Mobile Station B data. Students can
mark the location of the system using the arrows in the POINTER tray at the bottom of
the Gizmo. Students can also search for warm or cold fronts on the map.
Scientific Background
Although weather patterns are incredibly complex and notoriously difficult to predict, the basic
principles guiding weather patterns actually are fairly simple. Ultimately, air moves because of
density differences between different air masses. The density of air depends on two factors:
temperature and humidity, or water content:

As air heats up, air molecules move more quickly and tend to spread out. This makes
heated air less dense than cooler air.

Water molecules (H2O) have less mass than nitrogen (N2) or oxygen (O2) molecules.
Therefore, humid air tends to be less dense than dry air at an equal temperature.
Air that is less dense than surrounding air rises, resulting in a region of low pressure, or a lowpressure system. Air that is denser than surrounding air sinks, forming a high-pressure system.
Rising air in low-pressure systems tends to cool, which leads to
condensation and the formation of clouds. Low-pressure systems are
often associated with humid and rainy weather. Sinking air in highpressure systems tends to warm up as it descends. This discourages
condensation and usually results in dry weather.
In general, air moves from regions of high pressure to regions of lower
pressure, resulting in winds. If the Earth did not rotate, air would move
straight out of high-pressure systems and straight into low-pressure
systems. However, Earth’s rotation and shape cause winds to be
deflected, a phenomenon called the Coriolis effect. Air is deflected to
the right in the Northern Hemisphere and to the left in the Southern
Hemisphere. In the Northern Hemisphere, this causes air to circulate
in a clockwise direction around a high-pressure system and in a
counterclockwise direction around a low-pressure system.
Low-pressure systems are often associated with fronts, or boundaries between air masses. A
cold front forms along the leading edge of a cool air mass that is advancing into a warm air
mass. The dense, cold air pushes the warm air up at a steep angle, causing it to cool quickly. If
the warm air contains moisture, large cumulonimbus clouds will form. Intense thunderstorms or
snowstorms often occur as the front passes, followed by a period of clear and cool weather.
A warm front forms along the leading edge of a warm air mass that is advancing into cooler air.
The warm air rises over the cold air, cooling gradually. If the air is humid, stratus clouds form.
Gentle precipitation may occur, followed by clearing and warming.
Commonly, a low-pressure system will include both a cold front and a warm front. If the cold
front catches up to the warm front, the result is an occluded front. In this case the warm air is
lifted above the ground and several days of rain may occur.
Selected Web Resources
Weather station symbols: http://www.hpc.ncep.noaa.gov/html/stationplot.shtml
High- and low-pressure systems: http://www.atmosphere.mpg.de/enid/3sf.html
Coriolis effect: http://science.nasa.gov/headlines/y2004/23jul_spin.htm
Air masses and fronts: http://www.physicalgeography.net/fundamentals/7r.html,
http://www.phschool.com/atschool/phsciexp/active_art/weather_fronts/index.html
Related Gizmos:
Hurricane Motion: http://www.explorelearning.com/gizmo/id?427
Coastal Winds and Clouds: http://www.explorelearning.com/gizmo/id?438
Water Cycle: http://www.explorelearning.com/gizmo/id?435
Relative Humidity: http://www.explorelearning.com/gizmo/id?425