Practice 6: Constructing Explanations and Creating Designs

Thank you to Phil Brookhouse, MLTI Consultant, for this posting.

Students should share explanations and designs both in spoken and written form. Pages can serve as tool for written student explanations and SketchUp and Pages are great tools for sharing designs.  These two applications themselves are not tools specific to explanation or design, but using the thoughts from Frameworks stated above, they provide opportunities to “develop explanations of what they observe when conducting their own investigations”; “provide a basis for further questions”;” identify and isolate variables”; “use their measurements”; “rely on models or representations”; “use mathematics or simulations”; or ”generate and test possible solutions.”  We must support students to make explanations and designs supported by the creation of strong questions/problems, the development of clear models and investigations, and the application of rigorous data analysis and use of mathematical and computational thinking.

All eight practices of the Framework are interrelated.   The quote from Framework below explains the progression of skill for explanation (science) and design  (engineering,).

PROGRESSION FOR EXPLANATION

Early in their science education, students need opportunities to engage in constructing and critiquing explanations. They should be encouraged to develop explanations of what they observe when conducting their own investigations and to evaluate their own and others’ explanations for consistency with the evidence. For example, observations of the owl pellets they dissect should lead them to produce an explanation of owls’ eating habits based on inferences made from what they find.

As students’ knowledge develops, they can begin to identify and isolate variables and incorporate the resulting observations into their explanations of phenomena. Using their measurements of how one factor does or does not affect another, they can develop causal accounts to explain what they observe. For example, in investigating the conditions under which plants grow fastest, they may notice that the plants die when kept in the dark and seek to develop an explanation for this finding. Although the explanation at this level may be as simple as “plants die in the dark because they need light in order to live and grow,” it provides a basis for further questions and deeper understanding of how plants utilize light that can be developed in later grades. On the basis of comparison of their explanation with their observations, students can appreciate that an explanation such as “plants need light to grow” fails to explain why they die when no water is provided. They should be encouraged to revisit their initial ideas and produce more complete explanations that account for more of their observations.

By the middle grades, students recognize that many of the explanations of science rely on models or representations of entities that are too small to see or too large to visualize. For example, explaining why the temperature of water does not increase beyond 100°C when heated requires students to envisage water as consisting of microscopic particles and that the energy provided by heating can allow fast-moving particles to escape despite the force of attraction holding the particles together. In the later stages of their education, students should also progress to using mathematics or simulations to construct an explanation for a phenomenon.

PROGRESSION FOR DESIGN

In some ways, children are natural engineers. They spontaneously build sand castles, dollhouses, and hamster enclosures, and they use a variety of tools and materials for their own playful purposes. Thus a common elementary school activity is to challenge children to use tools and materials provided in class to solve a specific challenge, such as constructing a bridge from paper and tape and testing it until failure occurs.

Children’s capabilities to design structures can then be enhanced by having them pay attention to points of failure and asking them to create and test redesigns of the bridge so that it is stronger. Furthermore, design activities should not be limited just to structural engineering but should also include projects that reflect other areas of engineering, such as the need to design a traffic pattern for the school parking lot or a layout for planting a school garden box. In middle school, it is especially beneficial to engage students in engineering design projects in which they are expected to apply what they have recently learned in science—for example, using their now-familiar concepts of ecology to solve problems related to a school garden. Middle school students should also have opportunities to plan and carry out full engineering design projects in which they define problems in terms of criteria and constraints, research the problem to deepen their relevant knowledge, generate and test possible solutions, and refine their solutions through redesign.

At the high school level, students can undertake more complex engineering design projects related to major local, national or global issues. Increased emphasis should be placed on researching the nature of the given problems, on reviewing others’ proposed solutions, on weighing the strengths and weaknesses of various alternatives, and on discerning possibly unanticipated effects.

Below are links to the previous posts for each of these five practices.

Questions/ProblemsModelsInvestigationsData Analysis; and Mathematical and Computational Thinking.

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