Hands-on Activity Design and Fly a Kite

Learning Objectives

After this activity, students should be able to:

• Describe the concepts of lift and force.
• Explain and apply the steps of the engineering design process.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

Each group needs:

• 24-96 (or more!) disposable plastic drinking straws with a minimum 7-inch (18-cm) length and all of equal length; 6 straws per tetrahedron cell, which are combined to make up the tetrahedron kite; the number of straws needed depends on the complexity of the kite; for example, a simple kite made from 4 tetrahedral cells requires 4 cells x 6 straws = 24 straws, a 10-celled kite requires 10 x 6 = 60 straws, a 16-celled kite requires 16 x 6 = 96 straws, etc.
• lightweight sheet material, such as paper, plastic film, cloth etc., for covering the two sides of each tetrahedron cell; this is approximately one 8.5 x 11-inch (22 x 28-cm) sheet per tetrahedron cell
• string, yarn or rope, for connecting and creating the tetrahedron cells; about 45 inches (114 cm) per tetrahedron cell
• Design and Fly a Kite Pre/Post Quiz, two per student
• Construction and Competition Rules, one per group
• Guidelines for Running Tetrahedron Kites, one per group
• Engineering Design with Application to Unpowered Flight Worksheet, one per student
• paper and pencil, as needed, for sketching designs and drawing templates
• computer with internet access, for research

To share with the entire class:

• kite string, 25-30 feet (7-9 meters) per kite being flown; can be repurposed between kites if tests are not at the same time; rolls of kite string usually come in 500-foot (152-m) lengths
• scissors
• glue or tape
• kite handle
• a wide-open outdoor area on a windy day, such as a playground or field, for kite testing

Worksheets and Attachments

Pre-Req Knowledge

Knowledge of shapes, such as triangles (2D) and tetrahedrons (3D).

Introduction/Motivation

Kites may seem like toys, but they were once an integral part of weather forecasting, communication and war. Over time, kites have been replaced by airplanes, but their use has taught us a great deal about flight.

You may be familiar with Alexander Graham Bell for his invention of the telephone, but are probably less familiar with his great interest in achieving flight. One of his first "flying machines" was made using a kite-like design. One of the most interesting shapes he used for his kites was a tetrahedron—a solid-triangular pyramid. This tetrahedron shape can be stacked upon itself to create larger tetrahedrons, much like LEGO pieces can be stacked and combined into a bigger whole.

What is a tetrahedron shape? (Listen to student ideas.) The tetrahedron is a three-dimensional shape made of four equilateral triangles. It is a triangular pyramid. It has four triangular faces, six straight edges and four vertex corners. (If available, show students a tetrahedral block or an animation of one at https://commons.wikimedia.org/wiki/File:Tetrahedron.gif.)

The tetrahedron shape is popular for its advantageous strength-to-weight ratio, which means that for a given weight of a structure, in this case tetrahedrons, a large amount of force can be supported, which we call strength. This characteristic is derived from the geometry of the tetrahedron itself.

Procedure

Background

Engineering never has one answer and no perfect design exists. Engineers research all information accessible to them and identify multiple design strategies (in our situation, kites) that may work for their needs. Then engineers select the most promising design to build and test. Testing is a key step to enable engineers to learn vital information about their designs and helps them to identify unforeseen problems and weaknesses. For instance, in this activity, if a kite does not fly, then students examine potential reasons why it failed. Or if a kite breaks mid-flight, then students may seek to find a sturdier design. It is vital for students to understand that new designs do not have to work the first time, and even if they do, there is usually room for improvement.

In the activity, students start with a basic tetrahedral shape. Tetrahedrons are both strong and lightweight, which is key for achieving flight. Covering two sides of the tetrahedron shape can help create lift. Lift is the upward force on the tetrahedron created when wind hits the tetrahedron cell and is redirected downward. Multiple sets of smaller tetrahedrons can be connected into one larger tetrahedral kite, and the combined lift acting on each of the smaller tetrahedrons can overcome the weight of the entire kite. This usually enables the kite to take flight.

Consult the Building Tetrahedral Kites activity for details on how to fabricate a basic design for working tetrahedral kites with the potential for further manipulation.

Wind is a force. When it is blowing, you can feel it push you around. If the wind's force can be redirected downwards, you create what is called lift. Lift is a force that causes an object to rise in height, or fly/hover. Lift has a natural "enemy" known as gravity. Gravity is a force that brings things back towards the ground. If not enough lift is created by redirecting the wind and overcoming the force of gravity, an object won't fly. The problem may be rectified by either reducing the mass of the object being lifted (this reduces the force of gravity acting on the object) or increasing the lift to overcome gravity.

Before the Activity

• Gather materials and make copies of the Design and Fly a Kite Pre/Post Quiz, two per student; the Engineering Design with Application to Unpowered Flight Worksheet, one per student, and the Construction and Competition Rules and Guidelines for Running Tetrahedron Kites, one each per group.
• Use straws and string to make an example six-sided basic tetrahedron cell shape to show to students.
• Decide how you will enable students to access the Internet for the "research the problem" step of the activity, perhaps by using in-classroom computers, at-home computers (homework) or reserving a computer lab. Alternatively, screen a few online sources to find a variety of good designs and print out sheets to hand out to the groups.
• Arrange for the testing portion of the activity to take place outside on a windy day.

With the Students

1. Administer the pre-quiz, as described in the Assessment section.
2. Present to the class the Introduction/Motivation content.
3. Divide the class into groups of three students each and pass out the supplies, including the handouts.
4. Guide groups through the steps of the engineering design process as they design, test and refine their tetrahedron kites. Refer to Figure 1 for a flowchart of the steps, which are often performed in different sequences and repeated as necessary; review with the class, as necessary.

   

5. Ask: Identify the Needs and Constraints: (5 minutes) Read the tetrahedron kite construction rules and ask students to identify the design constraints, which are the project requirements and limitations. Have students create on their worksheets checklists of these constraints for their kite designs. Expect the checklist to look similar to this list:

• Needs to be able to fly in the wind.
• Each tetrahedron MUST use six disposable plastic drinking straws. (Show an example.)
• Each tetrahedron MUST be covered on two sides.
• Tetrahedrons may only be connected at the corners.

6. Research the Problem: (15-30 minutes) After students have completed their own checklists, they learn more about the problem and research possible designs.

• Discuss with students how a tetrahedron kite redirects the wind downwards to generate lift. See Figure 2.
• To give students an initial starting point for designing their own tetrahedron kites, have them research online to find a variety of different existing designs and examine them for whether or not they meet the activity design constraints and/or give them ideas for their own designs.

  

7. Imagine: Develop Possible Solutions: (20-30 minutes) Once students have spent some time researching different designs, have them brainstorm and sketch ideas for their own kite designs. Require each group member to create at least one sketch. Encourage students to be creative and consider all possible ideas.
8. Plan: Select a Promising Solution: Once multiple sketches have been generated, have student groups discuss the pros/cons of each design. Specifically, have students compare each sketch to their worksheet checklists. The selected kite design must meet all the design constraints. While it may not be clear if some constraints are met by the design until it is constructed and tested (for example, if it flies!), direct students to do their best to determine if the designs meet the identified constraints. It is okay to repeat the brainstorming, sketching and discussion process several times since exploring different ideas is part of the process of determining a final best design. Upon settling on a design, students begin construction.
9. Create: Construct a Prototype: (60 minutes plus drying time) Since the tetrahedron kite is modular (much like LEGO pieces, but with pyramidal shapes), take a moment to discuss the benefits of modular construction and how each team member can build a tetrahedron cell(s) that contributes to the whole. Once students finish constructing the cells, team members can start putting together the full design according to the original sketch. Expect construction to be a team effort.
10. Test and Evaluate Prototype: (30 minutes) Once the full kites are constructed, begin testing. It is best to wait for a windy day for testing since the lack of wind can yield false negative results (kite would fly in wind, but does not fly in the absence of wind). Review the guidelines.
11. Improve: Redesign and Retest: (60-90 minutes plus drying time as needed) Have each group share with the class its kite design and test results. Suggest that students look for common themes in successful kites. Have students think about why the other kites were not successful. For groups with successful, flying kites, have students consider ways to add more cells so that the kites are still able to fly. For groups with kites that did not fly, have students redesign how their tetrahedron cells are connected and re-attempt to fly. Re-confirm that the redesigned kites meet all constraints as outlined in the rules. Retest all groups' kites and expect to see an increase in successful kites.
12. Post-activity discussion: (10 minutes) At activity (or competition) end, lead a class discussion of the redesign results, as described in the Assessment section.
13. Administer the post-quiz, as described in the Assessment section

Vocabulary/Definitions

brainstorming: A group problem-solving method in which each person in a group presents his or her ideas in an open forum, with the purpose to come up with a great number of different ideas.

constraint: A limitation or restriction. For engineers, constraints are the requirements and limitations that the final design solutions must meet.

drag: A force that opposes the motion of an object traveling through fluid (including air).

force: The act of pushing, pulling or applying pressure.

lift: A force, opposite to gravitational force, created by fluid (air) flowing past an object.

modular: A system (such as a tetrahedral kite) that consists of multiple subunits that complete the whole design.

tetrahedron: A three-dimensional shape made of four equilateral triangles. A triangular pyramid. It may also be described has having four triangular faces, six straight edges and four vertex corners.

Assessment

Pre-Activity Assessment

Pre-Quiz: Administer the four-question Design and Fly a Kite Pre/Post-Quiz to assess students' prior knowledge of forces acting on kites in flight and the engineering design process.

Activity Embedded Assessment

Engineering Design with Application to Unpowered Flight: Students create a constraints checklist, make sketches and explain their design changes on the Engineering Design with Application to Unpowered Flight Worksheet. Look for evidence that students are thinking through their ideas and designs before construction begins. Encourage students to discuss and share test results of their initial kite designs; pay attention for thoughtful comments. The redesign step of the activity provides an opportunity for further assessment on how students evaluate and improve on their initial designs.

Post-Activity Assessment

Class Discussion: At activity (or competition) end, lead a class discussion in which students share their redesign results and gain practice in technical communication. Take note of students' discussion contributions to gauge their engagement and depth of comprehension.

Post-Quiz: Administer the four-question Design and Fly a Kite Pre/Post-Quiz again. Compare pre/post answers to assess individual student learning about forces acting on kites in flight and the engineering design process.

Troubleshooting Tips

It helps with construction if students create a template shape for covering the tetrahedrons, such as the covered planes illustrated in the orange color in Figure 2.

Additional Multimedia Support

An animation of a tetrahedral so as to comprehend its shape: https://commons.wikimedia.org/wiki/File:Tetrahedron.gif.

Building Tetrahedral Kites. (A middle school activity in which student teams construct tetrahedral kites following specific instructions and using specific materials in a limited time period, paying attention to basic manufacturing systems while aiming for team efficiency and product quality. A good source for a basic initial tetrahedral kite design.) TeachEngineering.org.

Illustrated online instructions for making a tetrahedral kite: https://boyslife.org/hobbies-projects/projects/1732/build-it/.

Copyright

Contributors

Supporting Program

Acknowledgements

The contents of this digital library curriculum were developed by the Renewable Energy Systems Opportunity for Unified Research Collaboration and Education (RESOURCE) project in the College of Engineering under National Science Foundation GK-12 grant no. DGE 0948021. However, these contents do not necessarily represent the policies of the National Science Foundation, and you should not assume endorsement by the federal government.

The author acknowledges the support and help from UC Davis RESOURCE advisors Alisa Lee, Travis Smith and Jean VanderGheynst. He also thanks the RESOURCE fellows for their helpful comments during the writing of the activity.