Tier 2: Impacts of Urbanization

Tier 2: Impacts of Urbanization

Objective:

Students will learn about temperatures of materials in outdoor environments, such as grass, light colored concrete, and blacktop. They will then work to engineer solutions that limit excessively high summertime temperatures, and produce public service announcements that educate the public about this phenomenon.

Overview:

Students will learn about heat absorption and reflection of light in different materials through hands on activities, articles, and websites. Students will perform investigations analyzing surfaces around their school or in the surrounding community, and how those surfaces change temperature during the day because of heat transfer, particularly through absorption of energy from sunlight. One particularly interesting dataset is from real-time pavement temperature sensors reported to the web by the Iowa Department of Transportation. Using their data and new knowledge, students are guided to understand the problems associated with excessive surface temperatures, air temperatures, and heat index levels and to develop solutions and public service announcements about them.

Big questions:

• What affects does the weather have on surface temperature (i.e., cloud cover versus clear skies)?
• What hazards could result from surfaces with elevated temperatures?
• What causes temperature differences in cities and rural areas?
• Why is it really hot in a corn field?
• Why do we build with certain building materials?

Standards addressed:

Tier in depth:

Engagement:  Is it ever too hot for an airplane to fly? (see https://www.wired.com/story/phoenix-flights-canceled-heat/).  What will happen in Iowa if Arizona-like temperatures occur here? Are the materials we use to build our infrastructure, or the crops we plant in our fields, causing our state to become hotter? Have students heard about any other examples similar to this one that affected people elsewhere? (If so, encourage them to investigate that phenomenon.)

NOTE:  For best mentoring of students, teachers should keep in mind whether student investigations can be approached by considering temperature only (such as heat transfer problems and deformation of blacktop pavement), or whether both temperature and humidity are involved (such as human comfort levels, water cycle issues and agricultural issues, need for air conditioning, and corrosion of materials).  As needed, teachers should review the concepts of dew point, soil moisture, evaporation, and heat index, and determine how to incorporate these into student investigations, data collection, and problem solving. One Iowa-specific source on this is Iowa Climate Statement 2017: It’s not just the heat, it’s the humidity! (and the sources at the end too). Iowa Climate Statement 2017: It’s not just the heat, it’s the humidity!

Part 1: Human infrastructure: All things absorb or reflect light in different amounts. This energy is then given off by objects as thermal energy. Over the course of time humans have altered their environment. Removing natural foliage and land cover and replacing it with buildings, blacktop roads, and concrete structures. The initial engagement activity for this lesson is to take students and have them carefully observe different environments. For example: take students into a grass field, to the school parking lot, and into the city where the students are surrounded by buildings and concrete sidewalks. At each location students are asked to make observations: What are their surroundings? What is the air temperature? What is the surface temperature of their surrounding? Etc. Students will then be directed to look at various data outlets, such as, https://mesonet.agron.iastate.edu/RWIS/?camid=IDOT-014 and any other sources that they may be able to find via Google search. The Iowa State Mesonet website will allow students to see the difference in air temperature and surface road temperature at the time of inquiry but also in the past.

The Environmental Protection Agency provides valuable data involving the areas classified as urban heat islands. Data and information that shows the impact that urban heat islands can have on infrastructure and people. https://www.epa.gov/heat-islands/heat-island-impacts Impacts that can be studied and used for problem solving exercises include elevated energy consumption, elevated emission of greenhouse gases and air pollutants, negative impacts on people’s health and comfort, and adverse to drinking water supplies.

Part 2: Natural Land Cover vs. Crop Land: Another analysis that students would do is look at evidence that shows how human planted crop land and other foliage affect surface temperature. One resource that could be used is NASA’s Earth Observatory Website https://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD13A2_M_NDVI&d2=MOD11C1_M_LSTDA. The areas with the densest vegetation (like the rain forests) always have a surface temperature lower than land that is striped or absent of vegetation. This article contains data that shows the difference in surface temperatures between agricultural fields and forests from locations around the Midwest including Iowa http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.449.821&rep=rep1&type=pdf. Besides using this article for the data it contains, it provides students the chance to analyze the data of real scientists who are working on investigating similar questions. During this section of the investigation students should be encouraged to perform their own investigations analyzing surface areas in their surrounding community. This can be accomplished with a basic thermometer.

Students should then be introduced to the concept of albedo. They should try and relate their findings from their independent studies of their temperature and materials study within their community, with NASA data on albedo. Does what they find support what scientists are saying about the correlation between albedo and surface temperature? Students should explain using data to support their claims. https://earthobservatory.nasa.gov/IOTD/view.php?id=84499

Part 3: Solutions: After investigation, data collection and interpretation, and understanding the issues — students should work to engineer solutions to specific temperature or heat index related problems.  Another good student-centered capstone activity on these phenomena are public service announcements that either warn about hazardous conditions, or educate the public on problems and/or solutions. As always, students should use data and other evidence to support claims.

Students Question (Sample):

What affects does the weather have on surface temperature (i.e. cloud cover vs. clear skies)?

What hazards could result from surfaces with elevated temperatures?

What causes temperature differences in cities and rural areas?

Why is it really hot in a corn field?

Why do we build with certain building materials?

*Students should be allowed to investigate any of their interests so long as they form an investigatory question

Experts:

Solutions:

Created Zach Miller (ia.zachmiller@gmail.com) and edited by Charles Stanier (charles-stanier@uiowa.edu)