SummaryStudents are introduced to the health risks caused by cooking and heating with inefficient cook stoves inside homes, a common practice in rural developing communities. Students simulate the cook stove scenario and use the engineering design process, including iterative trials, to increase warmth inside a building while reducing air quality problems. Students then collect and graph data, and analyze their findings.
Air quality and its impact on public health is an important area of environmental engineering. Environmental engineers trained to work with developing communities design appropriate, sustainable technologies with local materials to help improve quality of life.
Some experience graphing.
After this activity, students should be able to:
- Explain the health risks of heating and cooking indoors with inefficient cook stoves and how engineering can help improve air quality in developing communities.
- Make decisions to improve a design based on trial iterations.
- Create an x- and y- line graph showing the relationship between two variables.
- Identify maximum and minimum values on a line graph.
- Identify maximum and minimum rates of change based on the steepness of the line on the line graph (introduction to slope).
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Each TeachEngineering lesson or activity is correlated to one or more K-12 science,
technology, engineering or math (STEM) educational standards.
All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN),
a project of D2L (www.achievementstandards.org).
In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics;
within type by subtype, then by grade, etc.
Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.
All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).
In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.
- Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved. (Grades 3 - 5) Details... View more aligned curriculum... Do you agree with this alignment? Thanks for your feedback!
- Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved. (Grades 6 - 8) Details... View more aligned curriculum... Do you agree with this alignment? Thanks for your feedback!
- Represent real world and mathematical problems by graphing points in the first quadrant of the coordinate plane, and interpret coordinate values of points in the context of the situation. (Grade 5) Details... View more aligned curriculum... Do you agree with this alignment? Thanks for your feedback!
- Use variables to represent two quantities in a real-world problem that change in relationship to one another; write an equation to express one quantity, thought of as the dependent variable, in terms of the other quantity, thought of as the independent variable. Analyze the relationship between the dependent and independent variables using graphs and tables, and relate these to the equation. (Grade 6) Details... View more aligned curriculum... Do you agree with this alignment? Thanks for your feedback!
- Graph points on the coordinate plane to solve real-world and mathematical problems. (Grade 5) Details... View more aligned curriculum... Do you agree with this alignment? Thanks for your feedback!
- Visual displays are used to interpret data. (Grade 5) Details... View more aligned curriculum... Do you agree with this alignment? Thanks for your feedback!
- Earth and Sun provide a diversity of renewable and nonrenewable resources (Grade 5) Details... View more aligned curriculum... Do you agree with this alignment? Thanks for your feedback!
- Weather conditions change because of the uneven heating of Earth's surface by the Sun's energy. Weather changes are measured by differences in temperature, air pressure, wind and water in the atmosphere and type of precipitation (Grade 5) Details... View more aligned curriculum... Do you agree with this alignment? Thanks for your feedback!
Each group needs:
- grass, straw or hay (enough to cover a few "model house" roofs)
- aluminum foil disposable pan or ~2 feet heavy duty aluminum foil
- Popsicle® or craft sticks
- 2 feet string or twine
- Temperature vs. Time Worksheet
To share with the entire class:
- large fan
- bucket or cooler of ice
- heat lamp with 100 Watt bulb
- 2 temperature probes/thermometers with digital readout
- lighter or matches
- testing platform (a ~2' x 2' cardboard box)
- 6-10 sticks of incense (more if groups test multiple times)
- hot glue and/or duct tape
- roll of masking tape
- utility knife or box cutter (for teacher use only)
- pre-constructed foam core model house (made with four 13" wide x 13" long x 10-13" high foam core sheets)
Imagine you wake up early one morning, and it is below freezing outside. You think to yourself, "Brrr, it is so cold. I'll turn up the heater or take a hot shower to warm up." But, guess what? You have no electricity or gas, or running water for that matter. Well then, how are you supposed to warm up? This is not an uncommon situation for many families in communities around the world — specifically, people in "developing communities," or communities that do not have access to electricity, running water, or a way to get rid of waste and trash (such as a sewer system). In fact, in order to heat up their houses, many families in these communities use open fires (similar to camp fires) or stoves without chimneys to burn wood or sometimes dried cow dung because they do not have access to any other fuel. When the weather is very cold, families reduce the amount of heat that escapes the house by sealing up gaps and holes in the house or use their stoves and fires more frequently (which in turn emits more smoke inside the house). But what happens when you seal up your house and make a fire inside to heat it? Where does the smoke go? Unfortunately, the smoke from fires and stoves fills up the house, causing family members to become sick from the components in the smoke. Since they spend most of their days inside staying warm and cooking, it is often the mothers and young children in these households who get sick more frequently than the fathers and older children. Sickness from fire/stove smoke can include asthma, bronchitis and other serious respiratory (lung) problems. Sometimes, in the most severe situation, death occurs.
When families build their homes, they use many different types of materials for construction. The best materials to use are those that are better at keeping the heat inside the house for longer periods of time; in other words, they are good at "insulating" the house. Insulating materials are those that keep the indoor temperature from changing, which means that things meant to be cold stay cold, and things meant to be warm stay warm. Materials used for constructing houses around the world include adobe (clay and straw mixture), wood, metal, animal hides (teepees), snow (igloos), and even found objects such as tar paper, billboard/sign canvas, wood shipping pallets, and 55 gallon drums.
Engineers help families in developing communities in many ways. For instance, they are designing new ways to heat homes, such as "passive solar heating" (using the sun to heat the home and water), and inventing improved stoves for heating and cooking so that the smoke leaves the house through a chimney and does not remain in the living space where people breathe it.
This activity looks at some of the different materials people use to construct their homes in developing communities and investigate how well those materials work at holding heat inside the house when it is cold outside. Because heat rises, the focus is on designing a roof that keeps the heat inside the house for as long as possible. In addition to a focus on keeping heat in the house, we analyze how much smoke collects in the house. From this information, we can make qualitative judgments on the level of air quality by looking into the house through the window. After the first round of designing and testing a roof, we make improvements to the roof to hold the heat in for even longer while still reducing the amount of smoke in the house.
air quality: A description of the healthiness and safety of the air; a measurement of the pollutants in the air.
developing communities: Communities around the world that lack access to clean water and electricity.
insulating: A property of a material that allows it to prevent or slow the transfer of heat (change in temperature). An insulating material can keep warm things warm and cold things cold.
rate: A certain quantity or amount of one thing considered in relation to a unit of another thing; the relative speed of progress or change of something variable.
slope: The slope or gradient of a line describes its steepness, incline or grade. A higher slope value indicates a steeper incline. The slope is the rate of change.
This activity is designed to show students how different materials used in roofs and houses in developing communities vary in retaining heat inside a model house while the house is heating (while they are using a stove) and after the heat source has gone (after they stop using a stove). Students measure temperature every 20 seconds over three minutes of heating and every 20 seconds over three minutes after the heat lamp has been turned off. At the same time, students measure the temperature outside the house (between the house and a fan blowing cool air) to see the difference between the indoor and outdoor temperature. Additionally, smoke from a stove is simulated by a burning incense stick placed inside the house while the heat lamp is on, then removed when the heat lamp is turned off, showing how much smoke leaks out of the house during the course of cooling. This procedure emphasizes the trade-off between an airtight house that might hold in heat better (that is, a warm, smoky house) and a ventilated house that cools off faster (that is, a cold, ventilated house).
Before the Activity
- Make copies of the Temperature vs. Time Worksheet, one per student.
- Construct the house "platform," an overturned cardboard box, as illustrated in Image 2. Using a utility knife or box cutter, cut three holes in the bottom of the box:
- A hole large enough to place the heat lamp in so that the rim of the lamp sits flush with the surface of the box. Run the cord to the lamp out the bottom of the box so that the lamp can easily be plugged/unplugged (this method may be used for turning the lamp on and off).
- A second hole for the temperature probe/thermometer (be careful not to cut the hole too large so that the probe fits snuggly). Tape may be used to ensure the probe does not slip through the bottom.
- A small hole for the incense to sit in (tape may also be used to make sure they are held in well.
- Construct the foam core house with the following, as shown in Image 3:
- Four walls (no roof, as the students will construct these) and no floor (so that the house can be placed on the platform over the heat lamp, thermometer, and incense). Note: Walls can be hot glued or duct taped together. Dimensions for the foam core house should be roughly: base 13" x 13", minimum height 10" (floor to roof), maximum height 13" (floor to roof).
- Add at least one window (covered in plastic film) to the house so that students can look inside the house and see how the smoke concentration changes over time.
- A front door that opens/closes (made from cardboard or Popsicle/craft sticks)
- Fill any remaining gaps with masking tape.
- Make sure that the dimensions of the house are noted so that these can be given to the students when constructing the roof (that is, tell them that the roof needs to be at least 14 inches wide by 14 inches long so that it can fit onto, and overlap, the house walls).
- Set up the testing as shown in Image 2. (Please note, if temperature is insufficiently cool, place ice between the fan and the house, as demonstrated in Image 4.)
- Place the floorless/roofless house on top of the platform. Make sure thermometers are set up inside and outside the house so that students have easy access to the temperature readout on both.
- Place the fan roughly 3 ft from the house/platform; place the box of ice either between the house and the fan or directly behind the fan (as shown in Image 2 and Image 4). (Note: depending on the type of fan, the air may be cooler if the fan pushes it directly forward, rather than sucking it in from the ice behind the fan and then and pushing it back out through the fan. This difference is a great brainstorming opportunity for students to investigate the different cooling scenarios.)
- To get an accurate reading, students may have to hold the thermometer between the fan and house during the duration of the testing unless some kind of stand is used. (Note: if possible, a thermometer can be tied to a string hung from the ceiling. Ensure that the string is securely attached to the ceiling to avoid thermometer damage should the string fall from the ceiling.)
With the Students
- Optional: show students the Temperature Tells All Presentation to further introduce them to the activity.
Slide 1: Title slide.
Slide 2: Information about Langui, Peru, a rural developing community. Mention the following items to the students:
- Dung is the main fuel source. The surrounding area is heavily deforested from using all the trees and plants fuel.
- The main economic activities in Langui are:
o Agriculture is the primary source of livelihood
o Cattle breeding
o Processing dairy products like cheese and yogurt
o Breeding of poultry and guinea pigs
o Handmade looms and embroideries
- The last three activities from the above list are performed by women. The sale of guinea pigs, cheese, yogurt, looms and embroideries are performed in local fairs and the city of Sicuani (point out the round picture that pops from the slide).
Slide 3: These are examples of the house roofs and the materials from which roofs are constructed. Materials include thatch (made from hay) and corrugated tin. In one picture (bottom center), notice that a tarp was used as an additional layer to help with insulation. (Note: Ask students where they think community members get these materials.) Thin roofs are not very good at insulating the homes, which is a problem the community members face. But, the trade-off is that thicker more insulating roofs are more expensive than thin roofs. This is why a need exists for efficient, insulating materials for roofs.
Slide 4: This is how the insides of some of the homes look. Notice the inefficient cook stoves or open fire pits. The walls appear black in places from the smoke and ash from the fires. Typically, women spend the most time in the house for cooking, and also young children spend most of their time inside as well. The smoke creates very poor indoor air quality, so family members, especially the women and young children, often develop asthma, bronchitis or other serious respiratory (lung) diseases, which can lead to death.
Slide 5: Introduce the activity with this slide. The central question is how to design the roofs to keep the houses warm. We know we want to use insulating materials to hold the heat in the house. We also know there is a trade-off if we want to allow some of the smoke to escape, providing better air quality. Students may consider the pros and cons of having a chimney in the roof.
Slide 6: This slide shows the activity set-up to help students understand how they will test their roofs.
- After introducing the activity to students, show them the available materials and give groups five minutes to brainstorm and draw roof designs, deciding on a final design.
- Have one student in each group collect the necessary materials, based on the design.
- Instruct the groups that they have 15-20 minutes to build their roofs.
- Instruct students in each group to choose a "job" for the first round of testing. Jobs include: Time Keeper (holding the stopwatch and keeping time), Smoke Observer (peeking through the window and observing the presence and actions of any smoke), Light and Air Master (plugging/unplugging the heat lamp and turning the fan on and off at the appropriate times), and Temperature Master (reading the temperature from the temperature probes/thermometers).
- Direct students to record the temperature inside and outside the house every 20 seconds for 3 minutes with the heat lamp on and the fan off, and then for another 3 minutes with the heat lamp off and the fan on.
- Have all students record qualitative observations (written descriptions of the inside of the house in terms of how smoky it looks, etc.) at four points during testing: at the very start, when the heat lamp/fan are switched off/on (this is two times: once with the heat lamp on and the fan off, and then another time with the heat lamp off and the fan on), and at the end of testing.
- After testing, have students complete the first part of the worksheet based on their first test. Each student in the group should create one of the graphs.
- Lead a class discussion to compare the results of each group. Give students time to see designs from other groups and compare results.
- Based on what students learned from their own and other groups' results, have them redesign their roof so that it holds in heat but has better air quality.
- Repeat steps 4-9 for the second round of designs.
- Limit use of the box cutter and lighter/matches to the teacher only (for cutting holes in the testing platform and for lighting the incense). Once lit, warn students to use caution when handling the incense as it has a glowing tip, and can still burn skin.
- Remind students to be careful with the edges of the aluminum roof and when plugging/unplugging the fan and heat lamp.
- Do not allow cold water or ice to come in contact with the heat lamp or fan.
Before the activity, it is recommended that the teacher pre-bundle grass or hay into 0.5" bundles and individually tie each bundle with string/twine; 10 bundles per group is suggested for this activity.
Consider helping the students cut the aluminum pans, as the metal can be very sharp.
If the temperatures are insufficiently cold, try placing the ice between the house and the fan (see Image 4).
If difficulties arise with lighting the incense in the house, try lighting it outside of the house and then positioning it through the house door.
- Why did you choose these materials you used for your design? What are your goals?
- How will you determine if your roof is successful? Unsuccessful?
- What do you expect will happen when you test? What do you expect will happen with the temperature?
- What changes are you making for your second roof design? How did you make these decisions?
Brainstorming: Divide the class into small groups of three or four students each (consider using these same groups during the actual activity). Write the following questions on the chalk/white board or on an overhead. How do you think people in developing communities, who may not have electricity, cook and heat their homes? Do you think there are any risks or dangers that people in the US don't face? After a few minutes of brainstorming, ask student groups the questions out loud and discuss as a class.
Create-a-Poster: If time allows, have each group make a poster with a drawing of what a cooking/heat source might look like in a home in a developing community. Instruct them to write down reasons why this cooking/heat source is good and why it might be bad.
Activity Embedded Assessment
Re-Design Challenge: As students build and test, remind them that they need to pay attention to how well their design works, so that they can learn how to improve their roof for their second iteration. Ask students investigating questions, such as "how will you know if your design works well?" and "what could be improved?" Also, "what are potential problems with your design?" and "what aspects of the design should be kept the same?"
Data Collection: As students test their designs, have them collect data for the Temperature vs. Time Worksheet. They should record temperature readings for both inside and outside the home every 20 seconds on the worksheet, as well as collect qualitative data by describing the appearance of the inside of the home. Be sure to circulate through the classroom and check for completion to gauge student understanding and progress.
Graphing, Data Analysis and Introduction of Slope!: Have students complete the attached Temperature vs. TimeWorksheet after each round of testing is finished. Have them use the recorded data for inside and outside temperatures to find the difference between the temperatures (the relative temperature increase) at each time interval and the change in temperature between each interval. Have students create three graphs: temperature vs. time, difference in inside and outside temperature vs. time, and the change in temperature vs. time. Have students identify when the maximum and minimum temperatures occur, as well as when the maximum and minimum change in temperature occurs. Expect students to be able to identify that the line on the graph of temperature vs. time is the most steep where the maximum change in temperature is the greatest.
- For lower grades, instruct students not to complete the "Temperature Tells All" column for the difference in inside and outside temperature. Also instruct them to neither answer the questions based on this data nor graph the difference in inside and outside temperature vs. time. These omissions remove the "Introduction To Slope" part of the activity.
- For upper grades, use the conduction heat transfer equation to determine the heat transfer rate of the wall (Q=kA * (dT/dx)). (Provide k, the thermal conductivity of the foam.) (A= cross-sectional area of the wall, dT=inside temp-outside temp, dx=wall thickness.)
Construct and Test Roofs for Different Climates https://www.teachengineering.org/view_activity.php?url=https://www.teachengineering.org/collection/wpi_/activities/wpi_roofs_for_different_climates/roofs_for_different_climates.xml
Zero Energy Housing https://www.teachengineering.org/view_activity.php?url=https://www.teachengineering.org/collection/cub_/activities/cub_housing/cub_housing_lesson05_activity1.xml
A House is a House for Me https://www.teachengineering.org/view_activity.php?url=https://www.teachengineering.org/collection/wpi_/activities/wpi_a_house_for_me/a_house_for_me.xml
ContributorsCarleigh Samson; Odessa Gomez; Marissa H. Forbes; Jacqueline Godina; Janet Yowell
Copyright© 2012 by Regents of the University of Colorado.
Supporting ProgramIntegrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
The contents of these digital library curricula were developed by the Integrated Teaching and Learning Program under National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.
Last modified: August 10, 2017