Lesson Plans in Pollution Prevention
Structures and Models
Grades 6-8 (ages 10 - 14)
Science and Technology, Social Studies
After completing the exercises in this lesson, student will
- Understand the definitions and concepts of strength, stability and stress
- Begin to understand the effects of urban development on natural environments
- Work in teams to discover physical properties of structures
- Increase their ability to learn through hands-on or kinaesthetic activities
- Newspapers and/or magazines
- Masking tape
- Construction paper or newsprint
- Glue or tape
- Markers or crayons
- Pens or pencils
- urban development
- Creative thinking
- Problem solving
- Motor skills
- 20 minutes for lesson
- 30 minutes for activity
- home time (as needed)
- 15 minutes to judge and score
- Begin the lesson by defining and discussing strength, stress and stability. Help students to understand how these concepts influence decisions on what we construct in our cities and towns.
- Have students brainstorm a list of materials that provide enough strength to build structures. The list should include materials found in nature (e.g., wood, stone) and those that are made from natural materials (e.g., steel, concrete, and some plastics).
- Discuss with students the points to consider when preparing for new construction or repair of large city structures. These points should include safety, cost, time, labour, etc. Special attention should be paid to the life span of the structure; higher capital investment can often increase the life span of the project and reduce the frequency of maintenance, upgrades and replacement. Longer life span can decrease the amount of energy, pollution, and waste associated with the structure.
- Ask students to consider the environmental effects of building and developing human communities. For example, concrete surfaces drastically change water run-off patterns, and making the concrete in the first place generates tonnes and tonnes of greenhouse gases. Present students with fun facts, found at the end of this document, on environmental consequences of urban development and discuss the potential long-term effects on the Earth.
- Explain to students that they are going to build a model of a tower. The object is to build the tallest structure that can support a weight of a hard-boiled egg. Students are free to design their own structures, as long as the height can be easily measured, and the egg is fully supported by the structure. Students will also be asked to consider the environmental impact of their model and must therefore attempt to use as few construction materials, as a measure of resource conservation, as possible. Their model will be judged/scored against both the physical and environmental requirements of the structure.
- Provide each group of students sufficient building materials. Suggested materials for simple structures are newspapers, masking tape, and elastic bands, but could also extend to dried pasta, marshmallows, straws, paper clips, or plasticine. Explain to students that the mass of their structure will be used to represent the environmental quality of their structure; they should, therefore, aim to use as little material as possible.
- When structures are complete, score each project by first making sure that each model can support the egg and award 10 points for this achievement. Then measure the height of each tower and record this measure in centimetres. Finally, determine the mass of the tower (without the egg) and record that figure in grams. Calculate the final score by subtracting the mass from the height and adding the 10 points for supporting the egg. Using this scoring method will encourage students to maintain the function of their structure, while conserving building resources. (All students should be supplied with the same construction materials, so as not to be scored unfairly in the mass category.)
- Have students discuss as a class the overall project challenges of building a structure. What did they learn about strength, stability, and stresses? Were there any clear patterns or systems that worked for building structures? Have students also explain how they took conservation of material into account and how that contributed to pollution prevention. Did they have to compromise the strength or height of their tower in order to meet their conservation goals?
Assign further building projects (bridges, houses, etc.) to students, through the course of the unit. Ask them to design their projects with materials that would be used in a real construction project, so that they can complete a more accurate "environmental footprint" of the structure by taking into account the effects of producing, distributing, and manipulating the materials. For example, if their structure requires 20 tonnes of concrete, have them report how many tonnes of greenhouse gases are released in its production. Help them come up with alternative ways of building, or alternative materials, which decrease the amount of pollution and waste created by the project.
Students could mimic a contracting exercise by preparing a bid to construct a project for a municipality. The bids not only include a description of the project, with a proposed budget, but they also incorporate environmental attributes, such as materials used, life span, and anticipated repair and maintenance schedules. Encourage students to focus on the durability of the structure in their proposal, as this is one of the key methods of preventing pollution in the construction sector. Help students remember that successful proposals are ones that meet the needs of the project, while providing the best value for money.
Have students research sustainable buildings. Ask them to identify features that set these buildings apart from traditional structures and have them explain whether or not they think this sort of development could occur on a large scale. If these types of buildings provide the needs of the people who occupy and use them, why are they slow to become mainstream?
Set up a debate for students on the topic of environmental considerations in urban development. One side can argue that traditional methods of building and construction work best, and the other can argue that environmental considerations must be accounted for when pursuing development. Make sure that both teams address issues of human health and safety, as well as the cost of projects.
Environmental Fun Facts - Construction Industry
Did You Know…
- that one third of landfill waste, 9 million tonnes, is generated by the construction industry? (Alberta Roadbuilders and Heavy Construction Association and Alberta Transportation, 2002)
- that one litre of used oil has the potential to contaminate up to one million litres of drinking water? (Alberta Roadbuilders and Heavy Construction Association and Alberta Transportation, 2002)
- that a poorly tuned construction vehicle can emit pollutants equivalent to twenty properly tuned vehicles? (Alberta Roadbuilders and Heavy Construction Association and Alberta Transportation, 2002)
- that each year the amount of energy lost through uninsulated homes in the United States is equivalent to the amount of fuel delivered annually through the Alaska Pipeline? (U.S. Department of the Interior, 2000)
- that recycling steel and tin cans saves between 60 and 74% of the energy used to produce them from raw materials? (U.S. EPA WasteWise Program, 2002)
- that one tonne of recycled steel saves the energy equivalent of 3.6 barrels of oil and 1.49 tons of iron ore over the production of new steel? (U.S. EPA WasteWise Program, 2002)
- that, according to the Steel Recycling Institute, steel recycling in the United States saves the energy equivalent to electrical power for about one-fifth of American households for one year? (U.S. EPA WasteWise Program, 2002)
- that an average 2000 sq. ft. home uses almost 210 tonnes of aggregates (sand, gravel, etc.) in driveways, foundations, basements, sidewalks and streets? (Washington Aggregates and Concrete Association, 2002)
- that, in the year 2000, the state of Washington consumed 79 400 million tonnes of aggregates that replaced aging infrastructure, maintained highways and supported quality of life? (Washington Aggregates and Concrete Association, 2002)
- that about 50% of an average city is paved, including roads, driveways and parking lots? (Your Driving Costs, AAA, 1998 and EPA Annual Emissions & Fuel Consumption for an Average Vehicle, 2000, courtesy City of Temecula)
- that it can cost as much as $15 million to build one mile of a typical 4-lane highway? (Your Driving Costs, AAA, 1998 and EPA Annual Emissions & Fuel Consumption for an Average Vehicle, 2000, courtesy City of Temecula)
- that each tonne of cement replaced by an alternative reduces CO2 emissions by approximately one tonne? (EcoSmartTM Concrete, 2002)
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