Program of Studies

Overview: Structures can be found in both natural and human-constructed environments, serving a variety of purposes and taking a wide range of forms. In learning about structures, students investigate the properties of materials used, and test them under different loads and forces. They examine different ways that structural components are configured, analyze forces involved, and investigate resulting effects on structural strength and stability. As part of their study, students also examine construction methods used in the past and the present, and learn how science and technology link together in developing safe and efficient designs that meet human needs.

Key Concepts

The following concepts are developed in this unit and may also be addressed in other units at other grade levels. The intended level and scope of treatment is defined by the outcomes below.

Outcomes for Science, Technology and Society (STS) and Knowledge

Students will:

1. Describe and interpret different types of structures encountered in everyday objects, buildings, plants and animals; and identify materials from which they are made

• recognize and classify structural forms and materials used in construction (e.g., identify examples of frame structures, such as goal posts and girder bridges, examples of shell structures, such as canoes and car roofs, and examples of frame-and-shell structures, such as houses and apartment buildings)

• interpret examples of variation in the design of structures that share a common function, and evaluate the effectiveness of the designs (e.g., compare and evaluate different forms of roofed structures, or different designs for communication towers)

• describe and compare example structures developed by different cultures and at different times; and interpret differences in functions, materials and aesthetics (e.g., describe traditional designs of indigenous people and peoples of other cultures; compare classical and current designs; investigate the role of symmetry in design)

• describe and interpret natural structures, including the structure of living things and structures created by animals (e.g., skeletons, exoskeletons, trees, birds' nests)

• identify points of failure and modes of failure in natural and built structures (e.g., potential failure of a tree under snow load, potential failure of an overloaded bridge)

2. Investigate and analyze forces within structures, and forces applied to them

• recognize and use units of force and mass, and identify and measure forces and loads

• identify examples of frictional forces and their use in structures (e.g., friction of a nail driven into wood, friction of pilings or footings in soil, friction of stone laid on stone)

• identify tension, compression, shearing and bending forces within a structure; and describe how these forces can cause the structure to fail (e.g., identify tensile forces that cause lengthening and possible snapping of a member; identify bending forces that could lead to breakage)

• analyze a design, and identify properties of materials that are important to individual parts of the structure (e.g., recognize that cables can be used as a component of structures where only tensile forces are involved; recognize that beams are subject to tension on one side and compression on the other; recognize that flexibility is important in some structures)

• infer how the stability of a model structure will be affected by changes in the distribution of mass within the structure and by changes in the design of its foundation (e.g., infer how the stability of a structure will be affected by increasing the width of its foundation)

3. Investigate and analyze the properties of materials used in structures

• devise and use methods of testing the strength and flexibility of materials used in a structure (e.g., measure deformation under load)

• identify points in a structure where flexible or fixed joints are required, and evaluate the appropriateness of different types of joints for the particular application (e.g., fixed jointing by welding, gluing or nailing; hinged jointing by use of pins or flexible materials)

• compare structural properties of different materials, including natural materials and synthetics

• investigate and describe the role of different materials found in plant and animal structures (e.g., recognize the role of bone, cartilage and ligaments in vertebrate animals, and the role of different layers of materials in plants)

4. Demonstrate and describe processes used in developing, evaluating and improving structures that will meet human needs with a margin of safety

• demonstrate and describe methods to increase the strength of materials through changes in design (e.g., corrugation of surfaces, lamination of adjacent members, changing the shape of components, changing the method of fastening)

• identify environmental factors that may affect the stability and safety of a structure, and describe how these factors are taken into account (e.g., recognize that snow load, wind load and soil characteristics need to be taken into account in building designs; describe example design adaptations used in earthquake-prone regions)

• analyze and evaluate a technological design or process on the basis of identified criteria, such as costs, benefits, safety and potential impact on the environment

Skill Outcomes

Skill Outcomes (focus on problem solving)

Initiating and Planning

Students will: Ask questions about the relationships between and among observable variables, and plan investigations to address those questions

• identify practical problems (e.g., identify a problem related to the stability of a structure)

• propose alternative solutions to a practical problem, select one, and develop a plan (e.g., propose an approach to increasing the stability of a structure)

• select appropriate methods and tools for collecting data to solve problems (e.g., use or develop an appropriate method for determining if the mass of a structure is well distributed over its foundation)

• formulate operational definitions of major variables and other aspects of their investigations (e.g., define flexibility of a component as the amount of deformation for a given load)

Performing and Recording

Students will: Conduct investigations into the relationships between and among observations, and gather and record qualitative and quantitative data

• research information relevant to a given problem

• organize data, using a format that is appropriate to the task or experiment (e.g., use a database or spreadsheet for recording the deformation of components under different loads)

• carry out procedures, controlling the major variables (e.g., ensure that tests to determine the effect of any one variable are based on changes to that variable only)

• use tools and apparatus safely (e.g., select appropriate tools, and safely apply methods for joining materials; use saws and other cutting tools safely)

Analyzing and Interpreting

Students will: Analyze qualitative and quantitative data, and develop and assess possible explanations

• compile and display data, by hand or computer, in a variety of formats, including diagrams, flow charts, tables, bar graphs, line graphs and scatterplots (e.g., plot a graph, showing the deflection of different materials tested under load)

• identify and evaluate potential applications of findings (e.g., identify possible applications of materials for which they have studied the properties)

• test the design of a constructed device or system (e.g., test and evaluate a prototype design of a foundation for a model building to be constructed on sand)

• evaluate designs and prototypes in terms of function, reliability, safety, efficiency, use of materials and impact on the environment

• identify and correct practical problems in the way a prototype or constructed device functions

Communication and Teamwork

Students will: Work collaboratively on problems; and use appropriate language and formats to communicate ideas, procedures and results

• communicate questions, ideas, intentions, plans and results, using lists, notes in point form, sentences, data tables, graphs, drawings, oral language and other means (e.g., produce a work plan, in cooperation with other team members, that identifies criteria for selecting materials and evaluating designs)

• work cooperatively with team members to develop and carry out a plan, and troubleshoot problems as they arise

Attitude Outcomes

Interest in Science

Students will be encouraged to: Show interest in science-related questions and issues, and pursue personal interests and career possibilities within science-related fields (e.g., apply knowledge of structures in interpreting a variety of structures within their home community; ask questions about techniques and materials used, and show an interest in construction and engineering)

Mutual Respect

Students will be encouraged to: Appreciate that scientific understanding evolves from the interaction of ideas involving people with different views and backgrounds (e.g., recognize that a variety of structural forms have emerged from different cultures at different times in history)

Scientific Inquiry

Students will be encouraged to: Seek and apply evidence when evaluating alternative approaches to investigations, problems and issues (e.g., report the limitations of their designs; continue working on a problem or research project until the best possible solutions or answers are uncovered)

Collaboration

Students will be encouraged to: Work collaboratively in carrying out investigations and in generating and evaluating ideas (e.g., accept various roles within a group, including that of leadership; remain interested and involved in decision making that requires full-group participation; understand that they may disagree with others but still work in a collaborative manner)

Stewardship

Students will be encouraged to: Demonstrate sensitivity and responsibility in pursuing a balance between the needs of humans and a sustainable environment (e.g., consider the cause-and-effect relationships of personal actions and decisions)

Safety

Students will be encouraged to: Show concern for safety in planning, carrying out and reviewing activities (e.g., readily alter a procedure to ensure the safety of members of the group; carefully manipulate materials, using skills learned in class or elsewhere; listen attentively to safety procedures given by the teacher)