The reactor is unstable but can be fixed through modifications to the original design.

• Ask questions about what would happen if a variable was changed.

• Identify scientific (testiable) and non-scientific (nontestable) questions.

• Ask questions that can be investigated and predict reasonable outcomes based on patterns such as cause and effect relationships.

• Define a simple design problem that can be solved through the development of an object, tool, process, or system and includes several criteria for success and constraints on materials, time, or cost.

• Develop a diagram or simple physical prototype to convey a proposed object, tool, or process.

• Make observations and/or measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon or test a design solution.

• Make predictions about what would happen if a variable changes.

• Compare and contrast data collected by different groups in order to discuss similarities and differences in their findings.

• Analyze data to refine a problem statement or the design of a proposed object, tool, or process.

• Use data to evaluate and refine design solutions.

• Respectfully provide and receive critiques from peers about a proposed procedure, explanation, or model by citing relevant evidence and posing specific questions.

• Construct and/or support an argument with evidence, data, and/or a model.

• Use data to evaluate claims about cause and effect.

• Make a claim about the merit of a solution to a problem by citing relevant evidence about how it meets the criteria and constraints of the problem.

• Read and comprehend grade-appropriate complex texts and/or other reliable media to summarize and obtain scientific and technical ideas and describe how they are supported by evidence.

• Compare and/or combine across complex texts and/or other reliable media to support the engagement in other scientific and/or engineering practices.

• Obtain and combine information from books and/or other reliable media to explain phenomena or solutions to a design problem.

• Use evidence (e.g., measurements, observations, patterns) to construct or support an explanation or design a solution to a problem.

• Identify the evidence that supports particular points in an explanation.

• Generate and compare multiple solutions to a problem based on how well they meet the criteria and constraints of the design solution.

• Possible solutions to a problem are limited by available materials and resources (constraints). The success of a designed solution is determined by considering the desired features of a solution (criteria). Different proposals for solutions can be compared on the basis of how well each on meets the specified criteria for success or how well each takes the constraints into account.

• Research on a problem should be carried out -- for example, through Internet searches, market research, or field observations -- before beginning to design a solution. An often productive way to generate ideas is for people to work together to brainstorm, test, and refine possible solutions. Testing a solution involves investigating how well it performs undera a range of likely conditions. Tests are often designed to identify failure points or difficulties, which suggest the elements of the design that need to be improved. At whatever stage, communicating with peers about proposed solutions is an important part of the design process, and shared ideas can lead to improved designs.