Fellow name: Michael Hartinger

 

Title of Lesson: Urban Heat Island

           

School: Culver City High School

 

Grade Level: 9

 

Subject(s): Earth Science

 

 

Summary

This lesson will use the urban heat island effect to teach students how humans can affect local climate by changing local environmental conditions.  Students will be introduced to the concept that different materials can absorb/reflect/emit the sun's energy in different ways, and that this can play a role in what building materials are used for houses and other buildings.  Then, the students will be divided into groups and given thermometers to study one aspect of the urban heat island effect over a span of one week.  After the data collection is completed and the students have made conclusions, the urban heat island concept will be introduced.  A short presentation on how building materials in cities and the absence of water/vegetation can affect climate will be given.  Finally, in a second activity students will make suggestions for how to address the urban heat island effect in Los Angeles using what they have learned from the first activity.

 

In what way is your lesson/activity inquiry-based?

Students will use temperature measurements and other observations to study one aspect of the urban heat island effect – they will then make urban planning suggestions based on their observations.

 

Time Required

2 days

 

Group Size

5

 

Cost to implement

Thermometers (borrowed)

Shoeboxes (could be donated, or have students bring in)

Construction Paper and Tape (~$20)

 

Learning Objectives

After this lesson, students should be able to:

*Define local climate.

*List the things that can affect local climate.

*List the ways humans affect their local climate.

*Define the urban heat island effect.

 

Introduction / Motivation

For the first part of the lesson, we'll ask the students questions to explore the concept that different materials absorb/reflect/emit the Sun's energy in different ways.  Examples:  Why is it cooler at the beach compared to inland areas in the summer? Why is it warmer in the winter?

Have you ever walked across a parking lot at night after a hot, sunny day? What about through a park?  Which one felt cooler?

 

[Demo: When we introduced the concept of local climate, we had students answer a warm-up question – see Powerpoint "Albedo_intro"– then, we brought several types of building materials that had been sitting in the Sun (wood, wood painted white, black rubber) and had students feel the temperature difference between them]

 

The students will then be given an introduction to an activity (see below) where they test how different environmental factors can affect temperature.  They will record temperatures for several days.

 

Once they hand in their activity, we'll introduce students to the urban heat island effect.  We'll show a 2-minute video from the NSF/weather channel, then a Powerpoint with different examples of the urban heat island effect.  Finally, a second activity will be explained.  During this activity, students will make suggestions for reducing the heat island effect in Los Angeles.

 

Material to be covered on urban heat island (when this material is presented, examples will be given from different cities – e.g. satellite photo of Atlanta with average daytime temperatures superimposed):

 

 

Urban areas are typically hotter than surrounding rural areas by 2-5 degrees Fahrenheit on average, and the difference can be significantly larger than 5 degrees under the right conditions.  Urban areas tend to be hotter than more rural areas for many reasons.

*Less shade/ground cover

*The materials used in buildings/roads typically absorb a significant amount of the Sun's energy (especially darker materials)

*Reduced plant life – plants provide shade and release water into the air that dissipates heat.

*Clustering of building in cities – when buildings are close together, they can't release the heat they've absorbed from the Sun as effectively as if they were spread apart

*Human caused heating – Many human activities produce heat – for example, driving cars, running appliances.  In rural areas, there are fewer people and this heating isn't a big concern.  However, the activities of many people close together in an urban area can contribute to heating.

*Weather conditions – on sunny, calm days, the difference between urban and rural temperatures is largest in a given area – more energy is being delivered to the city because it is sunny, and less energy can be taken away, because there is no wind (less convection).

*Where the city is located – the difference between rural and urban temperatures in a given area can depend on the city's location – for example, the presence of a large body of water can help to lessen temperature difference (ocean breezes convect heat away from a city).

 

Negative impacts of urban heat islands:

*More energy required for air conditioning (can lead to rolling brown-outs or blackouts)

*Higher levels of air pollution due to increased energy demands (leads to burning of more fossil fuels) and more ozone formation at ground level (ozone can form more easily in higher temperatures, all other things being equal).

*Human health (heat stroke, dehydration, difficulty breathing)

*Artificially high temperatures can degrade water quality – for example, storm runoff from urban areas can heat streams/lakes/rivers where it is released, rapidly raising the temperature and harming aquatic life.

 

Possible ways to reduce the urban heat island effect:

*Change building materials – use lighter colors that reflect more visible sunlight.

*Increase vegetation in urban areas – on rooftops, for example.  In Los Angeles, use of the existing watershed could help greatly with this.

*Increase spacing between buildings.

*Reduce activities that generate heat.

 

 

 

Procedure

 

Activity 1:

Students will divide into groups of 4 and be given a data sheet, a thermometer, a shoebox, and construction paper.  Each group will then be asked to study one aspect of the urban heat island by pretending that the shoeboxes are buildings (they will not have been explicitly introduced to the heat island concept yet):

1)   How does vegetation affect temperatures inside the shoeboxes?

2)   How do different building materials affect temperatures?

 

Groups will be given a data table with some guidelines on how to record their observations and what type of observations to make.   However, they will have to design their own test to determine how each factor affects temperatures.

 

We will explain to the students that, for example, black colors absorb more heat than white colors.  They should pretend that the shoeboxes are houses, and that the construction paper is a type of roofing material. 

 

There is an open area with asphalt outside the classroom, as well as a small grassy area.  These areas could be used for comparisons between areas with different amounts of vegetation. 

 

Materials List

Each group will need:

*Data table

*Thermometer

*White and Black Construction Paper

*Shoe Box

 

 

Safety Issues

None

 

Lesson Closure

 

Activity 2:

We'll hand back Activity 1 to each group, as well as an article from the LA Times discussing the urban heat island effect in Los Angeles. (http://www.latimes.com/news/opinion/la-op-modarres9sep09,0,6511235.story).  Each student will be asked to make suggestions on how to reduce the urban heat island effect in Los Angeles using the data from Activity 1.  They will have two options for this activity:

a)    Write one or two paragraphs explaining how they would address one specific aspect of the urban heat island effect

b)   Draw two pictures of a city like Los Angeles – One before their solution is implemented, and one after.  They will have to label areas that are hot vs. areas that are cold. 

 

Is this lesson based upon or modified from existing materials? If yes, please specify source(s) and explain how related:

No

 

References

http://www.epa.gov/heatislands/impacts/index.htm

http://www.latimes.com/news/opinion/la-op-modarres9sep09,0,6511235.story

http://latimesblogs.latimes.com/greenspace/2010/02/lawns-turfgrass-soil-carbon-storage.html

http://svs.gsfc.nasa.gov/vis/a000000/a001000/a001049/index.html

http://earthobservatory.nasa.gov/Features/GreenRoof/

 

Attachments

Powerpoint with warm-up question and introduction to local climate ("Day 1 Albedo_intro")

Powerpoint with warm-up question and introduction to urban heat island ("Urban_heat_island Day 2")

Urban heat island lesson follow along (for students' notes)

Activity 1 handout 1 ("Handout1")

Activity 1 handout 2 ("Handout2")

 

List CA Science Standards addressed

     Science:  California Earth Sciences 6b: Students know the effects on climate of latitude, elevation, topography, and proximity to large bodies of water and cold or warm ocean currents.

 

Lesson Implementation Comments

 

How did the lesson or elements of the lesson work as desired?

The first activity worked well in that most groups observed that darker colored boxes heated up more than lighter colored boxes and that boxes on the grass were cooler.  Judging by the lesson closure activity, students got the main ideas of the urban heat island effect.  Giving students the option of drawing their ideas rather than writing them worked very well – some students put a lot of effort into the second activity, and came up with some really detailed designs for a cooler Los Angeles.

 

How did the lesson or elements of the lesson not work as desired?

There was one important issue that we were aware of with taking temperatures in the boxes but that still came up several times.  If the thermometer comes into contact with the sides of the box when taking temperature, it can greatly affect the temperature reading. We instructed the students to hold the thermometers steady, but several forgot to and took misleading data.  Another issue was that the ground temperature played a large role in the temperature of the box, as opposed to the Sun heating the box itself (although ground temperature is an important aspect of the urban heat island effect).  Finally, some students forgot to put both shoeboxes they were testing in the sun, which also led to misleading results.

 

What needs to be done or was already done to revise the lesson to make it more effective?

1)   Make sure more students bring in shoeboxes, or be prepared to re-use some.

2)   Devise some way to hold the thermometer in place inside the box so it doesn't touch the sides of the box.

3)   Remind students several times that they are testing the effect of the Sun on both boxes – if they still place one box in the shade, you can ask them later why they think they got different results from the rest of the class.

4)   If you don't want to include ground temperature and only want to test the effect of the Sun directly on the box, place thumbtacks into the bottom of the box so that the box stands on the thumbtacks rather than directly on the ground – this seemed to work well for us.