(Lesson courtesy of the Women in Engineering ProActive Network.)

Summary

In this lesson, teams of middle school students explore the engineering design process and the materials used in packaging by designing and testing a package that can protect a snack from heat and water.

Grade level: 6 – 8

Time: 80 minutes (Part 1: 30 minutes; Part 2: 50 minutes)

Learning Objective

After doing this activity, students should understand the basic engineering involved in designing food packaging, including constraints on materials, transportation,and costs. They will:

• Develop an understanding of engineering decisions related to advantages and disadvantages of process and products.
• Identify relevant design features for building a prototype to solve a given problem.
• Identify materials used to accomplish a design task based on a specific property.

Standards

National Science Education Standards.

• Identify a simple problem and a specific task and solution related to the problem.  [Grades K-4]
• Communicate the process of technological design, describing any completed piece of work and identifying the stages of problem identification, solution design, implementation, and evaluation. [Grades 5 – 8]
• Identify appropriate problems for technological design, identifying a specified need, considering its various aspects, and talking to different potential users or beneficiaries. [Grades 5 – 8]
• Scientific inquiry and technological design have similarities and differences. Scientists propose explanations for questions about the natural world, and engineers propose solutions relating to human problems, needs, and aspirations. Technological solutions are temporary and can have side effects and costs, carry risks, and provide benefits. [Grades 5 – 8]

Motivation   

Food travels a long way from where it is manufactured to when it reaches your mouth. Along the way it can be dropped, rained on, left on a cold loading dock, or spend time in a warm pocket. During that time, packaging protects the food from damage and contamination. Packaging engineers must work to ensure that food arrives in the best possible condition while using materials that are cost-effective and environmentally friendly.

Materials required per group:

• 3 or 4 snack foods with different packaging such as  candy, chips, cookies.
• Marshmallows
• Chocolate bars or squares
• Graham crackers
• Baking pan/aluminum pie plate
• Paper towels
• One measuring cup of water
• Stapler, masking tape, scissors
• Lightweight cardboard or cardboard from butter and light bulb boxes cut into 3” squares
• 6” x 3” pieces of aluminum foil, wax paper, and plastic wrap.
• Small foam plates cut in half
• Toothpicks

Other materials:

• 2 hair blowers
• 2 stop watches or watch with second hand

ACTIVITY

Students will analyze the packaging of snack food products currently on the market and design their own solution to a packaging problem. The activity has been developed based on a traditional engineering design process which pose key questions – all identified in boldface type, that help the students approach the problem as engineers.

PART 1: EXAMINING FOOD PACKAGING

What’s the problem? Snack food has to survive a rigorous journey from manufacturing site to when it is consumed. Evaluate the packaging of existing products to determine what methods effectively protect from conditions.

1. Lead a discussion on how food gets from a factory to your mouth. Make a list of conditions that food might experience.

2. Break the class into groups of 2 or 3 depending on amount of materials and size of class. Give each group an assortment of 3 or 4 snacks.

3. Have each group make a list of the materials used in their snack and identify which materials are used to protect the food from different conditions.

4. Lead a discussion on what broad categories these materials could be divided into. Ask the students which materials protect from which conditions. Ask them to consider which materials are recyclable.

PART 2: DESIGNING YOUR OWN SNACK PACKAGING

Create an activity sheet listing the cost of materials students can “purchase” to build their packaging. Have teams submit their “cost sheets” to tally which packages are the most and least expensive.

Who wants to know? A new candy company wants to package individually wrapped, ready to heat S’mores that can stay fresh in the wilderness or on a camping trip.

How can you help solve the problem? Use the knowledge of existing packaging as well as your own ideas to design packaging for ONE S’more.

1. Put the students back into groups and present students with the following problem: A new candy company wants to package individually wrapped, ready to heat S’mores – consisting of two graham cracker squares, a piece of chocolate, and a marshmallow. S’mores are often taken on camping trips and therefore subject to a variety of environmental conditions. After some testing, the condition that the engineers are having the most problems with is making their packaging weather proof. Design a package to protect one S’more from HEAT and WATER.

2. Give each group the following items: 2 paper towels; 2 graham cracker squares; 1 piece of chocolate; and 1 marshmallow; baking pan; one measuring cup of water; stapler; scissors; and tape.

3. Review the experiment together.

4. Arrange a “heat testing station” supervised by the teacher or an adult that includes one or two hair blowers and 1 or 2 stop watches or watches with a second hand. Students can time the test while the adult uses the hair blower.

5. Set up a “store” where students can purchase the packaging materials. Have the students submit their cost sheet so you can give them a “cost score.” The most expensive package gets 1 point, the least expensive package gets 8 points (if there are 8 groups). The rest are ranked in order of cost.

6. After a few minutes of planning, have one student per group come to the store with identifying the items their group has selected and the total cost.

7. As each group finishes their package, have the groups come to the testing station. Test the product and have the students complete the form

8. After testing, have each student group (or just two or three volunteers ) present their packaging design.

9. Lead a discussion evaluating the different designs presented. Which designs protect best against heat? Which designs protect best against water or contaminants?

Will your suggestion(s) work? Is your design feasible? How much material does it use? Is it

environmentally friendly?

Who can help you solve the problem? What type of information or knowledge is needed to understand food and packaging materials? Chemical engineers have knowledge of the reaction between food and materials. Mechanical and materials engineers understand packaging material properties including strength and heat transfer.

Engineering Summary: Finish with a discussion about how students approached the problem like engineers.

See why plastic is so popular in this short classroom video excerpt from The Changing World of Food Packaging:

[youtube]http://www.youtube.com/watch?v=YUdGecoDv0Q[/youtube]

Background Information for Activity Leader

Packaging for food serves to protect the consumables inside of it. Food packaging keeps goods from being damaged during shipping and keeps the contents fresh. During shipping, food can encounter a number of different environmental conditions ranging from drastic changes in temperature to rain or chemical exposure. Food packaging continues to be important once the product has been purchased. It aids the consumer in preserving and dispensing the food.

There are three major groups of materials used to package food: flexible, semi-rigid, and rigid. Flexible materials include paper (laminated and waxed) and plastic films. Aluminum foil, paperboard, and formed plastic are in the semi-rigid category. Metal, glass, and thick plastic are considered rigid materials.

Paper, plastic, and aluminum foil are popular packaging materials in the snack food category. Plastic packaging materials are the most versatile as they are able to vary dramatically in shape and strength. Resistant to air, moisture, and in some cases light, plastic is used in bags, wraps, and bottles. Recycled plastic products can be manufactured into high tech lumber, trash cans, and even new plastic containers. Aluminum is the cheapest material that can block light, air and moisture. However, aluminum can react with certain food products adversely affecting tastes and storage. Paper products are popular as a packaging material because they are easy to customize. Special laminates can be used to make paper resistant to water. Paper products are also the only packaging material that comes from a renewable natural resource.

A material’s ability to protect food from changing temperatures depends on the thickness of the material and how well (or how poorly) the material conducts heat. Paper, plastic bags/wrap (polyethylene), and cardboard are the poorest conductors of heat. Styrofoam and glass are slightly better conductors of heat while aluminum and other metals are excellent conductors of heat.

Questions to Ask

As you go through this activity with the students you should encourage them to think about which types of food packaging they’ve found to be useful.

Additional questions to ask:

Q. How do companies decide which kind of materials to use in their packaging?

A. Food packaging needs to protect the food, be environmentally responsible, and be economically feasible for the company. The cost of the materials needed heavily influence decisions. The weight of materials as well as the size of packaging also has a significant impact on decisions as larger, heavier packaging increases shipping costs.

In addition, the more material used, the less environmentally friendly and cost-effective it will be.

Q. Is the ability to recycle a material the only Factor that makes it environmentally friendly?

A. No. The ability to recycle a material is one aspect of being environmentally friendly. It is also important how much material is used overall, and how much energy is needed to manufacture a product. If a great deal of heavy equipment and machinery is needed to create a material more pollution (air, water, thermal), is generated.

Activity Extensions:

• Students can design and test for other packaging situations.
• Conduct a crush test to see how well the packaging withstands weight.
• Have students create posters identifying snack packaging materials and detailing which are recyclable or biodegradable.
• Advanced students can use thermometers or probes to quantitatively calculate which materials provide better heat protection.

Additional Resources

• Packaging Digest’s Food & Beverage Packaging site features innovative new products, such as edible wrappers and chocolate packaging that promotes wildlife awareness.
• Michigan State University’s School of Packaging, opened in 1952, is the nation’s oldest program for packaging engineers.
• Nestle food packaging engineers explain what they do. YouTube video [2:27]

Zero-packaging food store? Portlandia’s rats sense opportunity in this computer-animated spoof:

[youtube]http://www.youtube.com/watch?v=MM5AFoB6GJ8[/youtube]

Filed under: Grades 6-8, Lesson Plans

Tags: activity, Engineering Design Process, food packaging, lesson, Packaging Engineering, S'mores, snack