Design and Build a Better Candy Bag

Build Materials (For each team)

Required Materials

• 8” x 12” pieces of thin, plastic material (we suggest cutting either a plastic painters drop cloth or plastic sheeting )
• Scotch and Masking tape
• Twine
• Crayons/Markers

Testing Materials

• Scale
• Measuring cups
• Candy, blocks, pebbles, rice or another item to use as weight

Materials

• Scale
• Measuring cups
• Candy, blocks, pebbles, rice or another item to use as weight

Process

Test the strength of each team’s bag design by having a team member hold the bag by the handle(s) while placing weight into the bag (piece by piece). The object is to force the bag to fail by adding too much weight. Once the bag fails, weigh the bag and contents. Document the weight each bag was able to hold before falling apart and calculate the bag’s volume for comparison between teams. The volume is calculated by measuring the length, width and height of each bag. Then, calculating the volume = length x width x height.  

Each team will then redesign and build a second bag, then complete the testing process again. The goal is to have their second bag hold more weight than the first.

Design Challenge

You are a team of engineers given the challenge of designing and building a sturdy, functional and attractive bag to hold candy. The bag should have a handle(s). You will predict the bag’s volume and weight capacity.

After building and testing your first bag, you will redesign and build a second bag and test again. 

Criteria 

• Bag must have a handle(s).
• Give attention to how attractive the design is. 

Constraints

• Use only the materials provided. 
• Teams may trade unlimited materials. 

1. Break class into teams of 2.
2. Hand out the Design and Build a Better Candy Bag worksheet, as well as some sheets of paper for sketching designs. 
3. Discuss the topics in the Background Concepts Section. Have a discussion about the manufacturing of paper bags and provide several examples of bag designs to share. Ask students to compare the bag designs and guess which might hold the most volume and the most weight.
4. Review the Engineering Design Process, Design Challenge, Criteria, Constraints and Materials. 
5. Instruct students to start brainstorming and sketching their designs.
6. Provide each team with their materials.
7. Explain that students must develop a candy bag that is sturdy, functional and attractive. The bag must have a handle and be designed to hold the materials selected for testing (candy, blocks, pebbles, rice,etc.) The goal is for the bag to hold the weight of as many of the items as possible before filling up or falling apart.
   
   Students will design, build and test their first bag and then redesign, build and test a second bag. The goal is to have their second bag hold more weight than the first.
8. Announce the amount of time they have to design and build (1 hour recommended).
9. Use a timer or an on-line stopwatch (count down feature) to ensure you keep on time. (www.online-stopwatch.com/full-screen-stopwatch). Give students regular “time checks” so they stay on task. If they are struggling, ask questions that will lead them to a solution quicker. 
10. Students meet and develop a plan for their candy bag. They agree on materials they will need, write/draw their plan, and present their plan to the class. Teams may trade unlimited materials with other teams to develop their ideal parts list.
11. Teams build their designs. 
12. Test the strength of each team’s bag design by having a team member hold the bag by the handle(s) while placing weight into the bag (piece by piece). The object is to force the bag to fail by adding too much weight. Once the bag fails, weigh the bag and contents. Document the weight each bag was able to hold before falling apart and calculate the bag’s volume for comparison between teams. The volume is calculated by measuring the length, width and height of each bag. Then, calculating the volume = length x width x height.
    
    Each team will then redesign and build a second bag, then complete the testing process again. The goal is to have their second bag hold more weight than the first.
13. As a class, discuss the student reflection questions.
14. For more content on the topic, see the “Digging Deeper” section.

Student Reflection (engineering notebook)

1. When you tested your prototype, what was the approximate volume of the bag? 
2. How much weight did your bag hold? 
3. Did you have to redesign your initial prototype? If so, why? What did you discover because of your redesign? If not, why do you believe your prototype worked so well the first time? 
4. What is one thing you liked about your design? 
5. What is one thing you didn’t like about your design?
6. What is one thing you would change about your design based on your experience?
7. What technology, science, and mathematics concepts did you use when you designed the prototype?

The lesson can be done in as little as 1 class period for older students. However, to help students from feeling rushed and to ensure student success (especially for younger students), split the lesson into two periods giving students more time to brainstorm, test ideas and finalize their design. Conduct the testing and debrief in the next class period.

Paper Bag History and Inventors 

Over the years a variety of designs for candy bags have been created. They are built of a variety of materials (paper, plastic, cardboard) and are designed in a variety of shapes. A woman inventor from York, ME, named Margaret Knight (1838-1914) is credited with inventing a process for automatically folding and gluing paper to form the square or rectangular bottom of a paper bag. As a child, Margaret was often designing, or redesigning mechanical parts for everything from kites to sleds. When she grew up, she initially worked at the Columbia Paper Bag Company in Springfield, MA. At the time, paper bags were folded and glued much like envelopes. After her work hours, Margaret began to design a machine part that would automatically fold and glue the square or rectangular bottoms needed for paper bags. 

Finally, she came up with a design that she thought would work. She had a Boston machinist create an iron model of the part so that she could apply for a design patent. Initially, her design was ignored as the workmen in the factory questioned what a “woman would know about machine design.” Margaret Knight did receive a patent for her machine in 1870, but she had to go through a lawsuit first with a man named Charles Annan who had attempted to steal her design and patent the machine himself! Now, Margaret Knight is often considered the mother of the grocery bag. She eventually partnered with a Newton, MA man and started a company in Hartford, CT in 1870 with her invention: the Eastern Paper Bag Company. Now, Margaret’s machine is on display at the Smithsonian Institution in Washington, DC. Visit www.smithsonianlegacies.si.edu/objectdescription.cfm?ID=92 to view a photo of her machine.

• Constraints: Limitations with material, time, size of team, etc.
• Criteria: Conditions that the design must satisfy like its overall size, etc.
• Engineers: Inventors and problem-solvers of the world. Twenty-five major specialties are recognized in engineering (see infographic).
• Engineering Design Process: Process engineers use to solve problems. 
• Engineering Habits of Mind (EHM): Six unique ways that engineers think.
• Iteration: Test & redesign is one iteration. Repeat (multiple iterations).
• Prototype: A working model of the solution to be tested.
• Volume: the amount of space the object takes up. In other words, volume is a measure of the size of an object, just like height and width are ways to describe size.
• Weight capacity: Amount of weight a container can hold.

Internet Connections

Project Lead the Way
National Council of Teachers of Mathematics’ Principles and Standards for School Mathematics

Recommended Reading

Margaret Knight: Girl Inventor, by Marlene Targ Brill (Millbrook Press, ISBN: 0761317562)
Packaging Prototypes: Design Fundamentals, by Edward Denison and Richard Cawthray (Rotovision, ISBN: 2880463890)
50 Trade Secrets of Great Design: Packaging, by Stafford Cliff (Rockport Publishers, ISBN: 1564968723)

Writing Activity 

Write an essay (or paragraph) explaining how a cardboard milk carton has been designed to be strong enough to hold its liquid contents. 

Alignment to Curriculum Frameworks

Note: All Lesson Plans in this series are aligned to the U.S. National Science Education Standards (produced by the National Research Council and endorsed by the National Science Teachers Association), and if applicable, to the International Technology Education Association’s Standards for Technological Literacy and the National Council of Teachers of Mathematics’ Principles and Standards for School Mathematics.

National Science Education Standards Grades K-4 (ages 4 – 9)

CONTENT STANDARD A: Science as Inquiry

As a result of activities, all students should develop

• Abilities necessary to do scientific inquiry 
• Understanding about scientific inquiry 

CONTENT STANDARD B: Physical Science

As a result of the activities, all students should develop an understanding of

• Properties of objects and materials 

National Science Education Standards Grades 5-8 (ages 10 – 14)

CONTENT STANDARD A: Science as Inquiry

As a result of activities, all students should develop

• Abilities necessary to do scientific inquiry 
• Understandings about scientific inquiry 

CONTENT STANDARD B: Physical Science

As a result of their activities, all students should develop an understanding of

• Properties and changes of properties in matter 

Principles and Standards for School Mathematics (ages 6 – 18)

Data Analysis and Probability Standards 

– Instructional programs from prekindergarten through grade 12 should enable all students to: 

• formulate questions that can be addressed with data and collect, organize, and display relevant data to answer them.
• develop and evaluate inferences and predictions that are based on data.

Standards for Technological Literacy – All Ages

Design

• Standard 8: Students will develop an understanding of the attributes of design.
• Standard 9: Students will develop an understanding of engineering design.
• Standard 10: Students will develop an understanding of the role of troubleshooting, research and development, invention and innovation, and experimentation in problem solving.