Urban Weather Investigations
Author: Sarah Pounders
Overview
Click image for larger version (Used courtesy of NASA)
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Weather is a challenge for all gardeners, but urban landscapes have
unique climate issues caused by man's manipulation of the land,
including including the phenomena of heat islands and excessive runoff during rainstorms.
In this lesson, students will investigate urban temperature and
rain patterns.
Objectives - Students will take data and make observations of temperature, rainfall, and stormwater runoff patterns, and discuss the impact these might have on their school garden.
Standards (Microsoft
Word document)
Materials:
- thermometers
- rain gauges (You can purchase gauges or make your own using directions
at Making
Weather Tracking Tools)
- notebooks for use as weather journals
- cake pans (old ones or new foil ones)
- potting soil
- grass seed
Background
Urban conditions can add to the weather challenges of gardeners.
Man-made surfaces such as asphalt and concrete, along with objects
like buildings and cars, significantly increase temperature. As rain
falls on thousands of roofs cascades onto paved surfaces, it creates
runoff rather than being slowed by foliage and absorbed by soil,
as it does in natural environments.
Laying the Groundwork
1. As a class, research the term urban
heat island effect. What is this phenomenon? What
causes it? How might it affect your ability to
grow plants in the city? Click
here for a good discussion about heat islands from the
EPA.
2. Next, research the problems associated with
stormwater runoff in urban areas. How does this impact plants and
gardens in
the city?
Check out Rain
Gardens to the Rescue for additional background information.
3. Ask students to think of ways to explore whether
these phenomena affect their schoolyard.
Exploration
To investigate temperature patterns:
1. Take students to your
schoolyard and choose a variety of areas to
investigate (near buildings, in full sun, in shade, near streets,
in areas with vegetation, and in areas without vegetation). Use
a thermometer to take data for a temperature journal. In the journal,
carefully label and describe each site, and take readings at each
one over the course of several days.
2. When you return to the classroom, summarize your results on
a chart. To stimulate discussion, ask students, Did you find any
differences?
Why do you think you found these differences? How did the temperatures
compare on different days?
Next, investigate water runoff patterns:
1. Before a rainstorm, have students place rain
gauges in various sites around your schoolyard (open areas, under
vegetation,
near
buildings without
gutters, and near buildings with gutters). After the storm, have
individuals or teams record measurements in weather journals.
Also give students time after
the storm to make observations
of water patterns on the
ground (areas of standing water, signs
of what happened to the rain when it fell, and where it went. Back
in the classroom, discuss what their data and observations might
data mean. Ask students, Did each of the gauges catch the same
amount of water? What does this say about the impact of rain on different
locations
in our schoolyard? Did you find evidence that stormwater might
have an impact our school garden?
Making Connections
Model rainwater patterns in the classroom to help demonstrate your
findings:
1. Fill two old cake pans with soil. In one pan, plant grass seed
and let the seed grow for about a week to establish some roots.
Leave the second pan unplanted.
2. Tilt both pans and simulate rain onto the soil using a watering
can. What happens? (The soil in the pan without plants will erode,
but the soil in the pan with roots should stay in place.) Ask students
to think about the implications of stormwater erosion in the schoolyard.
3. You can modify the experiment by creating a third pan with mulch
covering the soil and a fourth pan filled with plaster to simulate
concrete. Compare each surfacing and make conclusions about the
impact of different types of surfaces on your environment.
Branching Out
- Invite a local meteorologist to talk to you class about local
weather patterns.
- Research global climate change. Ask students to read articles
that both support and refute this phenomenon and discuss how
and why opinions vary.
- Research urban greening and its
impact on the heat island effect
- Build a rain
garden! The
Low Impact Development Center provides some rain garden templates.
Also check out our feature, Rain
Gardens to the Rescue.
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