Design Your Shopping Bag Lessons

In designing your shopping bag lesson plan, your probably won't get very far without doing the activity yourself. Just as students need to become familiar with the materials and the product they are designing, you'll need hands-on experience with shopping bags before designing your lessons.

With a personal investigation under your belt, you'll probably find an overall outline for the activity handy -- you can get this by reviewing the three-phase Video Timeline for this task. You should be ready to apply a modified Grant Wiggins-style Backward Design approach to creating your own shopping bag lesson. Briefly, this involves asking: "What understanding do I want my students to achieve?" and "What evidence will demonstrate such an understanding?" (Wiggins says you should really start with answers to these questions, then pick tasks that will support students in achieving these goals. By having the shopping bag task already in mind, you would then be doing something akin to reversed backward design!)

Here is a short list of possible skills and concepts that you might consider aiming for with your students:

1. Develop a shared vocabulary for describing different bag designs and their performance when loaded.
2. Conduct experiments so that students test a single design variable per iteration.
3. Communicate to other classmates the results of testing and design suggestions (see Design Rules-of-Thumb).
4. Describe bag redesign decisions via explanations based on experimental results.
5. Predict and diagnose bag failures accurately, and explain choices using appropriate terminology.
6. Work collaboratively in groups, with an awareness of different roles played and needed by a team.

Select some or all of these goals, or other goals related to Standards, and ask, "How could my students demonstrate these understandings to me and others?" You can then structure your lessons so that they support students' growth towards these objectives. Do you want your students to do qualitative testing of bags to failure (by hand or foot), or quantitative testing? Should they choose bag materials or will you just give them paper lunch bags to convert into shopping bags? Do you want kids to have more or less tape for reinforcement? Will you show students any DITC videos -- as with Bag Types & How They Fail?

You may want to review DITC's Ways of Naive Designers page in preparing this lesson. In planning this activity, you might also want to review What's Hard About a Topic as you identify key concepts and devise powerful questions that you want students to address. In addition, you may want to think about which one design strategy you might choose to emphasize with this task by reviewing pages in What Is Design? For instance, the Research design strategy is well represented in students' scavenger hunt and ensuing discussion.

Questions

Here are some questions you might use to check students' understanding of key concepts related to shopping bag and their redesign.

1. Do a triad sort of the three shopping bags shown to the right. This involves putting two bags in one group, and leaving the third bag by itself. How are the two bags similar? How is the third bag different? Was your triad sort based on characteristics that were more surface or deep features? (See the research on Surface/Deep Categories)

2. What is the advantage of putting a flat, thin piece of cardboard in the bottom of a shopping bag? What kind of failure does it help if present?

3. MOVIE 1 at the top of this page shows a hybrid shopping bag design that mimics the function of a backpack. Start the movie and pause it when cued so that you can predict where you think this bag -- which may be new to you -- will fail. After, finish watching the rest of the movie to see if your prediction was correct.