Discussion Diamond Graphic

8.A Systematically evaluate competing design solutions based on jointly developed and agreed-upon design criteria using systematic processes to show how small changes in one design characteristic might cause unexpected changes in other design characteristics.

• As students are explaining their top two changes in teams, listen for each team member using the data from previous investigations and how those relate to the criteria and constraints to justify their choices.
• As teams begin their consensus discussion, listen for students to surface potential negative effects of changes as they decide on which changes are best to implement.
• Look to see they are using their Design Testing Matrix to support their arguments.

What to do

Circulate while teams are working to look at individual student notebook entries and listen for discussions during consensus building that are explicitly considering whether the changes will ensure the device will still align with the criteria and constraints. If students are only using the data to talk about more or less energy transfer, ask probing questions about why those data can be used as evidence to support their ranking to encourage them to put the data in the context of the criteria and constraints.

If you don’t hear students pushing back against others’ ideas for changes during the consensus discussion, look at team members' written responses to find differences in suggested changes and set these changes up against each other while encouraging students to weigh in. Prompt them to check their Design Testing Matrix to consider any potential negative effects of a change (in addition to the positive effects that relate to the criteria and constraints). Use prompts similar to those below to encourage students to use evidence to be critical of choices:

It looks like there are some ideas for changes that are the same, but there are several ideas that are different. Are all the effects of each of these changes equal?

How are the other criteria and constraints affected when these changes are made?

Do any of these changes have some possible negative effects?

How can we know if a positive effect of a change outweighs the possible negative effects?

Discuss the consensus process and how to be more confident with their design choices. Ask students how they felt about the process of reaching consensus on the criteria they thought were important to change. Display slide E. Say, Many of you may feel like you need more time to talk these ideas through and haven’t yet come to a consensus. That is OK. We will have more time to consider these decisions, but let’s take a moment to take stock of our progress. Turn and talk with a neighbor to discuss these prompts:

How did you feel about the consensus process?

Were there any disagreements about which of the criteria to change or how to change them?

Are you sure you are making the best decision?

How did using your Design Testing Matrix help you have purposeful discussions?

What would we need to do to be confident we were making the decisions that would optimize our design?

Suggested prompt

Sample student responses

As I walked around the room during the team discussions, I noticed that some teams came to consensus relatively easily, while others had a harder time making a decision about which criteria or constraints to change. I heard similar patterns during this discussion as well. What did you all talk about in your teams?

• Our team pretty much had the same two things that we all wanted to change, but we just wanted to change it slightly differently.
• Our team couldn’t really decide; some people thought certain criteria were a lot more important than others.
• It was hard to make a decision sometimes because some people just cared about certain parts of the design more than other parts.
• It’s hard to make a final decision without seeing exactly if the design will work better or if there is something that we won’t expect.