Teachers TryScience

Investigation 1: Introducing the Challenge and Defining the Problem

Assumptions:
This lesson, as written, assumes that students have had minimal experience with the practices, CCCs, and DCIs at this grade band, and therefore should be considered an early step in students’ progressions across the elements of the dimensions included here.

Materials
Various bags or containers of chips (Pringles, Lays, Tostitos, etc.)
Scales (scales must be sensitive enough to register the weight of an empty bag of chips)
Evaluation Worksheet

Instructional Sequence
Pre-assessment entrance tickets- At the start of class, give students two minutes to write about the following prompt: If you were to design the perfect food package, what elements would you include? Collect the ticket. This will allow students to consider their prior knowledge, air misconceptions, and begin thinking through questions that they have about the process.

Begin a group discussion by asking students if they’ve ever opened a bag of chips and noticed some crushed chips towards the bottom of the bag. Ask students how they think the chips got crushed? Where and how does the chip travel to get from a factory to your hands? Finally, ask students what they think can be done to prevent chip crushing? (Responses might include more protective packaging or more careful handling of food materials during the shipping process.) At this point, it might be helpful to create a visual list of student ideas or a diagram of student thinking about the process of chip packaging and shipping and factors influencing chip crushing. This will allow students to refer back to some of the original thinking when necessary, as well as provide an opportunity to revisit and refine ideas throughout the lesson. This will also give you an opportunity to highlight the science ideas they may be explicitly or implicitly referring to, such that they can develop those more deeply later in the lesson.

Ask students what factors product engineers might have to consider when creating different types of packaging for shipping or display. Encourage students to think about the entire system from production to sale. Responses might include durability, cost, and performance of different materials. If you made a visual list or diagram of the factors influencing chip crushing, use this opportunity to have students relate their ideas to their previous thinking, and represent the new ideas about the process of production, packing, and shipping on the list or diagram. You can frame this as describing the system, and ask students to think about the different components of the system- how are they defining the system? What are the important inputs, outputs, and processes?

Tell students that today they’ll be focused on chip packaging, and investigating 1) what happens to chips between where they are created and when they get to you to eat, 2) why those things happen, and 3) how we can use what we know to make sure the most intact chips get to us. Next, present students with various chip containers. Tell students that they will be examining not only the features of the container but also the number of crushed chips per container.

Split students into six small groups, and give two groups a Pringles container, two groups a Lays bag, and two groups a Tostitos bag.

You can create additional student groups or add in additional types of chip packaging by having groups examine more than one bag, but be sure that for each type of chip packaging at least two groups are collecting data. When grouping students, consider creating groups to support struggling students, English language learners, and students with special needs.

Ask the groups to consider the total number of chips, the number of broken chips, the weight of the empty packaging, and the features of the packaging. Encourage them to think about the fact that different bags of chips have different numbers of chips- how would we control for this and still show accurate data, and be able to make accurate interpretations? Encourage them to think about proportions and percentages, and why they might want to use this to give them more accurate information. Ask students to record their data in a way that will allow them to easily organize their group’s data and present it to the class. For struggling students, you may consider providing students with chart or table. Once students have had time to record their data, ask each group to share out verbally while other groups record the data, such that every group has a set of full class data. Be sure that they calculate and articulate the percentage or proportion of broken chips per bag.

Tell students that their goal is to determine what contributes to chips staying intact or breaking, and ask them to think about how to organize the class data to help them see these patterns and relationships. Ask students what would facilitate seeing those relationships? A graph or a chart from the data? A diagram? To help some learners, you can turn this section into a worksheet to guide their data collection.

As you walk around, ask students about similarities and differences they may see in their data, and what other considerations they might need to think about. For more advanced students or students who finish quickly, ask them to consider correlation vs. causation (in simpler language, if students do not have a strong understanding of ‘correlation’ yet) in their interpretations of the patterns- can they tell, so far, what caused the chips to break? Or do they need more information to shift from a correlational account to a causal account? When you are probing for this type of thinking, it may help to ask students about alternative claims or interpretations for the data, especially if they lead with “yes, the chips broke because of X”- you might ask other students in the group to provide an alternative cause, or you may provide this yourself. Encourage students to use their thinking about correlation vs. causation later, when they are investigating the science and designing solutions. This will also be helpful for you to become aware of student misconceptions in regard to the science as well as ideas underlying causal relationships, which you can revisit throughout the lesson.

Once every group has had a chance to think about the class data, ask the class if they notice any patterns in the data? Does it seem like certain packaging features protect chips better? Listen for science background here. What are other considerations we need to be thinking about? What else would we need to know to make stronger claims about the packaging? Listen for ideas underlying correlation vs. causation here. Emphasize that in order to make stronger claims, students would need more data to work with. It is difficult to generalize based on two bags per type of packaging.

Be sure to ask probing questions during class discussions. Guide students to make claims using the evidence they collected and their own reasoning based on prior experience or knowledge. This will allow you to formatively assess student performance on the task, and will allow you to probe how students are using practices and conceptual understandings. These types of questions will also help prepare students for the culminating writing task at the end of this lesson. You can also use these questions to better connect to students’ personal experiences and interests. For example, asking “What can be done to prevent chip crushing?” allows students to pull evidence from the data they collected and to use their past experiences with chip packaging to support their claims.

Now, ask students why each set of chips doesn’t come in a steel container. Wouldn’t that prevent any chips from breaking? Bring students back to their original thoughts about the process of chip packaging and shipping as they think through this, updating any classroom diagram that you might be creating to facilitate student thinking. (Students might bring up shipping costs, but other responses could include that steel packages would be too heavy for workers to lift or too expensive to produce.) By asking students about system components and processes, you may be able to help see students apply their understanding of system interactions. This is an opportunity to explicitly probe students understanding of the crosscutting concept.

After eliciting student responses, focus students’ attention on shipping costs. Ask students if they know how much a stamp costs (many students will not know.) What about shipping a small package? For homework, ask students to use the United States Postal Service website https://www.usps.com/ to research how much it would cost to ship the chip container they examined earlier. Remind them to refer to the container weight they recorded to help guide their research.

As an additional accommodation, you could explore the USPS website as a class or in small groups during class time rather than assigning this as independent homework.

During the next class period, ask students to share out their findings about shipping costs. You may notice differences in prices even among students who examined the same chip container. Some students may have elected to ship the container using a larger box, while some might have researched the price for a padded envelope.

Tell students that they will now use their data from examining the chip containers as well as the shipping prices they researched to create the best chip package. If needed, take a few minutes to discuss the concepts of modification and optimization. Ask students to think about how you might go about doing this – using a concrete example may help students think about this. Give them some time to think of ideas, and then share with a small group. Facilitate a whole class conversation about the importance of designing based on:

• How and why the problem happens (that it’s important to understand any scientific information the relates to why the problem is happening)
• What do we want, and what do we have available? (criteria and constraints)
• Testing and assessing how the design did- what worked? What didn’t work? What did we learn?
• What changes can we make? What are the most important changes to make, and why?
• Making changes based on our tests.

As you listen to students discuss these ideas, listen for misconceptions students may have that you can help them address during the design and modification process. Make sure you revisit this conversation during the design and revision process.

Inform students that they will be using common materials to design and construct a package for a single chip. Each group will get the same type of chip of roughly the same size. The job of each group is to design a package that will not only protect the chip, but is also lightweight. They will be sending the chip through the mail. Tell students they will then evaluate their design when the package comes back using a specific formula. Pass out the Evaluation Worksheet, and take time to review the formula as a class. As an additional accommodation, you can revise the worksheet so it is more scaffolded. You may need to remind students about order of operations.

Each group will record the following information for the package upon its delivery through the mail system.

1. Mass of the package in kgs to at least 3 significant figures.
2. Volume of the package in cubic centimeters to at least 3 significant figures.
3. Intactness score of the chip on the following scale:
   • 100 Points: like new, perfect
   • 50 Points: slightly damaged; cracked but still in one piece
   • 10 Points: broken in 2 - 5 pieces
   • 5 Points: broken in 6-20 pieces
   • 1 Point: broken into more than 20 pieces; crumbled

Groups will then determine the overall score for each package using the following equation:

Overall Score = Intactness score / [mass in kg x volume in cm³]

Example:

mass = 0.145 kg volume = 240 cm³ intactness score = 100
Overall Score: 100 / [0.145 kg x 240 cm³] = 2.87

Ask students, as a group, to sketch out a package design based on the observations they have made, analyzed, and interpreted so far. As you walk around, ask students questions to make them think about what they still don’t know- what do they expect to happen, and why? Are there other issues (listen for science ideas) that may contribute?

Then ask students to individually take a few minutes to think about and write down what other information they still need to know- what questions do they still have? Ask students to share their questions with their group, and come up with some key questions, as a group, they want to answer to make their design better. Have a classroom discussion about these, referring back to student ideas about design and modification from the previous classroom discussion. Lead students to the idea that the better they understand the science of why the chips get crushed, the better their design to prevent chip crushing will be.

Investigation 2: Forces Acting on the Package

Materials
Multiple bags of chips
Scales (scales must be sensitive enough to register the weight of an empty bag of chips)
Meter sticks
Items of different masses

Instructional Sequence

Tell students that before moving on to the actual design of the chip packaging, they first need to think about what types of situations the chip might encounter during shipping. Ask students to think about times that they’ve seen a package being moved or delivered (this can be in real life or on television). What types of forces do the packages encounter? Have students work individually to create an annotated diagram of the different forces the chip might encounter during different parts of the delivery system. Responses might include boxes being dropped or thrown as well as boxes being crushed under heavier loads. Use this drawing as a tool to assess students understanding of forces.

Once students have listed some of the forces that a package might encounter, tell students that they will investigate the difference between chips that break because they are dropped and chips that are crushed. Ask students to think about how the forces in those two situations are different - what is causing the pushes and pulls in the two situations? These could include gravity, mass of involved objects, movement of the transport mechanism causing pushes and pulls, other objects, etc. Ask students to think about what they know about forces and how this could influence the effects of different forces acting on the chip as they do their investigation. Students could draw or write down their ideas, as something they can update or refine throughout their investigations, and use this to help design their solutions to the chip packaging problem. Since students discussed systems and processes earlier, this may be a good place to ask students to think about the system(s) they are examining; they could even consider the limitations of their drawing in representing the system.

Split students into small groups. Half of the groups should investigate crushing and half the groups should investigate dropping.

For the students who are investigating dropping, provide meter sticks and instruct them to investigate dropping the chip packages from three different heights. They should test at least 3 bags per height, and after each drop, they should count the number of broken chips. Be sure that they record their data in their science notebooks.

For the students who are investigating crushing, provide the scales and items of different masses. Instruct students to subject the chips to objects of three different masses, and tell them they need to subject at least 3 bags of chips per object. They should count the number of broken chips each time. To guide them in selecting objects that aren’t too heavy, ask students to think about which objects would be likely to crush a chip package during the shipping process? Be sure that they record their data in their science notebooks.

Depending on the needs of your students, you can allow them more freedom in designing this investigation, or you can add more scaffolding. Be sure that students understand that they should use a new bag for every test. As you walk around to different student groups, ask them questions about what they are seeing, and ask students to think about patterns and cause and effect as they describe what they witness in their test.

After each set of groups has had a chance to collect their data, have the class share out and record the class set of data on the board. Use probing questions to help students make claims about the data. Is there a certain point where dropping yields more broken chips than crushing does? Which forces need to be kept in mind when designing a chip package? Ask students to update their drawing or description, if this was used or to create an annotated drawing if they haven’t done so yet. Be sure they indicate the forces acting on the packages. Students should be able to indicate that in both cases, there are forces pushing up and down on the chips.

Finally, as a class, discuss how the data they collected and their drawing might inform their design. Prompt students to reference specific data in their responses as evidence for their ideas.

For students with high interest, you could add another investigation that asks students to think about the structure of the chip. Provide students with ruffled chips and smooth chips and ask them to design an investigation that will give them insight into how the structure of the chip might help distribute the forces acting on the chip in different ways. They can then use their findings to inform their packaging design.

Investigation 3: Designing

Preparation

At the end of this investigation, you will be mailing out students’ chip packages so be sure that you are familiar with postal regulations and the approximate time it will take for the chips to arrive back at the school. Additionally, we suggest that you try designing your own chip package prior to implementing this with students. Not only will this allow you to identify potential issues with mailing, it will allow you to identify areas where students might struggle.

Materials

• 1 chip per group
• 1 preaddressed mailing label to your school per group (There should be a space for the group to indicate their group name or group number)
• Paper, cardboard, boxes, envelopes, glue, tape, string, cotton balls, plastic wrap, toothpicks, popsicle sticks, foil -- other materials you have on hand that are safe to mail. Be sure each team has the same materials available to them.

Instructional Sequence

At this point, ask students to revisit everything they have encountered so far. Ask them to gather information from their investigations, drawings, and data analysis to design a great package for a chip. Ask students to revisit the evaluation process and identify the given criteria and constraints that will drive their design.

Now that students have been introduced to the challenge as well as the evaluation process, split students into smaller groups.

Allow students to examine the materials available to them, but do not allow them to build until they have created an annotated drawing of their design.

Approving student designs before building will allow you to identify problems that students might run into and to redirect their thinking if needed. It will also aid with materials management. The most common issue students run into is designing a package that can’t go through the mail. If needed, refer students back to the USPS website to get them thinking about what can and cannot be shipped.

Prompt students to consider the work they did in investigations 1 and 2 as they create their design. As you walk around the room, make sure you encourage students to think about the following ideas, and that you see evidence of students using:

• Scientific information
• Criteria and constraints of the design
• Updating their thinking as the design process is underway, framed by their understanding of the problem, science, and criteria/constraints. Note that the design process can be a really helpful way for students to deepen their understanding of the content included in the DCIs and CCCs. Look for conversation and questions that demonstrate students are engaging in this way, and support students who are struggling to use the concrete design process as a way to better engage with the science.

Once you have approved students’ designs, allow them to build.

Finally, once all groups have finished building and have applied their labels, they should give you their packages (with the chip sealed inside) to ship.

Investigation 4: Evaluating and Redesigning

Materials

• Evaluation Worksheet

Instructional Sequence

Once all packages have arrived back at the school, it is time to weigh and evaluate the contents of the packages. Create evaluation teams consisting of students from several different groups so that each package is scored fairly. Each team can evaluate multiple packages by rotating through stations. Instruct students to use their Evaluation Worksheet to record their findings.

After each package has been evaluated, it is time to examine the packages as a whole class. For each package, have the design group explain the features of their package, including how features of the design contributed to the function of the package, and give other students an opportunity to ask questions of the group presenting, reminding them to provide respectful critiques that are based in evidence. Then have the evaluation groups compare their scores. It there are discrepancies in scoring, have students discuss decisions in scoring, acknowledging where discrepancies may arise, and then calculate the average overall score.

Once all packages have been presented, ask students to write an individual reflection based on the following prompt “If you were to redesign your package based on the presentations you just saw, what changes would you make and why?” Tell students to be sure to consider all of the information from the design (including science and all observations) as well as the evaluation process.

After students have had the opportunity to write and submit their reflections, ask the whole class what features/materials made for the best package. Record student responses on the board, making sure you ask students to think about why those factors made for the best packages, probing students application of the practices, science and engineering DCIs, and crosscutting concepts. Encourage students to make specific claims about how observable features of the package impact the functionality. Revisit the modification conversation from earlier in the lesson, this time in the context of this specific design problem.

Ask students what feature they think is most important for the design- make this question intentionally a little vague and very open ended, to encourage students to think of a number of different responses- and encourage students to share their reasoning. Write the student ideas somewhere all students can see. When students share different ideas and different reasoning, point out that students may be using different criteria as their “most important criteria” for the design, or that students may be identifying multiple features that contribute to a specific criteria that could be considered when they redesign.

Use this conversation to emphasize that there may be no perfect design, and that engineers often have to think about tradeoffs. For instance, a package may result in an intactness score of 100, but might be very heavy which decreases the overall score. Ask students to share what other factors they considered when creating their packaging. This is another opportunity for students to demonstrate their understanding and use of the crosscutting concept.

Instruct students to return to their design groups. Ask students what they think the next steps should be to continue making their devices better, encouraging a conversation about iteration. Explain to students that iteration, or refining and retesting, is a key part of the engineering design process. Instruct groups to use their responses to the reflection prompt to begin sketching out ideas for how they would redesign their chip package.

Iteration is an important aspect of the engineering process. You should have students actually build a second design, test it and then evaluate it using the same method as investigations 2 and 3. If you do not have enough time for a full redesign and retest, focus on the annotated blueprints the students are making in Investigation 3.

Writing Task

Materials

Copies of Writing Performance Task Rubric

Instructional Sequence

Before students begin working on their argument, ask students to share what they think constitutes a strong scientific argument. After a few responses, review the Writing Performance Task Rubric.

Then, present the following writing task.

Use the evidence from your testing, evaluation, and research to create a written argument addressing whether your group’s redesign is the optimal design for chip packaging.

Depending on student familiarity with argumentation, students may be provided more guidance. For example, students may need to be told to provide claims, evidence, and reasoning; to consider all the possible claims and the evidence that supports each claim; to ensure that they address why their design may be better than alternative designs; to offer respectful critiques of other designs that they observed, or to suggest alternative ideas for modification.

As an extension, in addition to the individual writing task, you can have student groups prepare formal presentations of their optimized designs. Additionally, you could have students from the same group compare their arguments, asking them to consider:

• Did group members make different claims or use different evidence or reasoning to support their claims?
• Are those claims, evidence, and reasoning valid?
• What questions could you ask group members to better understand their thinking, and to determine whether the evidence supports one claim versus another?