Writing and sketching reflections in a student journal with the design process and testing of the kite’s flight.

Student Journal

Guide - Platonic Solids

Learn about the kite throughout history and the experiments made from the hands of many inventors.

Extra Kite Activity Booklet

In this lesson, explore the rich history of kite flying, as well as the different types and purposes of kites. Learn about inventors who played a key role in the development of kites and investigate the forces at work to make kites fly. Experiment with flying a tetrahedron and then collaborate to build and fly a larger Sierpinski pyramid kite.

#### Lesson Structure

When students go through this lesson in each section the objectives they will learn are:

* **Warm-up** – Learn about kite design as a phenomenon throughout the ages.
* **Imagine** – Learn about the principles of flight-the balanced and unbalanced forces acting on a kite to cause it to fly.
* **Create** – Create a tetrahedron kite out of a single pyramid.
* **Build** – Combine pyramids to create and fly a Sierpinski kite. 
* **Reflect** – Reflect on challenges to building and flying a kite.
* **Challenges** – Opportunities to extend your thinking and prototyping skills through a fun variety of challenges! 

#### After this lesson students will be able to:

* Summarize a brief history of the development of kites and the multiple purposes throughout the ages.
* Evaluate why kite designs, uses, and applications have changed over time. 
* Differentiate between different types and parts of kites.
* Build a kite using the modules of the Sierpinski triangle.
* Expand upon existing kite prototypes to solve practical and real-world challenges.
* Determine the forces acting on the kite and record observations from multiple attempts to fly the kite.
* Experiment with making design adjustments to be able to fly the kite successfully, and justify design changes.

Teacher Notes

Overview and Objectives

Materials

Facilitation and Collaboration Work

#### Before Starting (20 min)

These are suggestions to prepare on your own before starting this lesson with your students.

* Build a tetrahedron from the [Create](#create) section of this lesson. (10 min)
* Optional: Share, download and print the Pre lesson - Platonic Solids asset and give to your students. (5 minutes)
* Optional: There is an extra asset called the Kites Activity Booklet with the tetrahedron kite building steps, sketchbook, and with an additional template with instructions to make a Lebanese paper kite. (5 min)

#### Vocabulary 

This is the list of vocabulary terms used throughout the lesson. They will be in **bold** and the definition listed throughout the different sections. On the **Sierpinski Kite Flying Forces - Student Journal** asset there is also a list of definitions. Students can always revisit the vocabulary definitions with media and questions in the lesson.

* **Tetrahedron** (noun) - A special form of the polyhedron that features four triangular faces, also recognized as a triangular pyramid. 
* **Tetrahedral** (noun) - Consisting of four faces. 
* **Cellular** (adjective) - Modular, consisting of parts that resemble separate cells or boxes.  
* **Aerial** (adjective) - Occurrence or an action performed in the air or atmosphere. 
* **Altitude** (noun) - Elevation above a given surface, such as the ground or the sea level. 
* **Force** (noun, verb) - An outside influence, in the form of a push or pull, that creates a change in direction or speed. Forces have both an amount and a direction.  
* **Drag** (noun, verb) - Friction caused by wind moving over a surface, also known as air resistance. 
* **Lift** (noun, verb) - Upward force generated when a fluid moves over a curved surface.
* **Tension** (noun) - Force that results from a line or rope pulled in two opposing ways.
* **Sail** (noun) - Large, flat, or curved surface of the kite which gets pushed into the air.  
* **Bridle** (noun) - A short line of string that attaches to two points on the kite.  
* **Tow Point** (noun) - The connection point between the kite’s line and its bridle.
* **Sierpinski** **Pyramid** (noun) - Self-similar arrangements of smaller pyramids composing a larger pyramid structure. Named after Polish mathematician Wacław Sierpiński.

Preparation

### Facilitation and Collaboration Work

Students can read and answer questions independently or as a group.

#### History of Kites 

* Kites have a rich history around the world. Early records show kites being flown in China and around the second century BC for military purposes. One such military endeavor involved the order to extend a kite over a city’s fortifications. In doing so, the Chinese general Hsan Hsin learned valuable information about the extent of the city’s defenses. This intel was used to aid their forces in secretly tunneling the right amount under the city. It  culminated in both a successful and stealthy attack on that settlement. There are also some records that show kites may have been flown as early as 9000 BC on the Indonesian island of Muna in ceremonies after harvest. One piece of archaeological evidence on this particular island is a cave painting of a kaghati kite. This type of kite, which combines natural elements such as pineapple fibers, local leaves, and bamboo skin, is still used today by present-day people of Muna.  
* Kites began to spread from China to other parts of Asia, and each region cultivated their own modes, forms, and uses for kites. As kites made their way to India, the fighter kite was developed. Another particularly creative kite innovation were flute kites from Vietnam. Flute kites began to be flown around 1000 AD, and are still flown today. Flute kites are made by attaching a flute to a kite.  Both the kites and flutes are made by hand and labor-intensive.  The flutes are formed from old bamboo, with holes drilled in at exact locations to produce certain sounds.
* By the 1400s, kites had traveled from Asia to Europe, brought first by the stories of travelers like Marco Polo. Later, in the 1500s and 1600s, sailors carried kites from their voyages to Japan and Malaysia. It was not until the 1700s that kites both became very popular with children and also began to be used for science experiments and meteorology. Ben Franklin’s experiment in 1752 relied upon the use of a kite, conductive wire, and a key to demonstrate the connection between electricity and lightning. 
* In the 1800s, kites were critical to the study and research of flight. An impressive list of figures including the Wright Brothers, Sir George Cayley, Samuel Langley, Alexander Graham Bell, and Lawrence Hargrave all tested ideas with kites, furthering knowledge and theories about aeroplanes. The 1800s and 1900s also witnessed a burgeoning of new kite designs. There was even a fascination with man-lifting kites, for surveying and military use. While less needed with the advancement of the airplane, kites still had important functions in World War I and II. In World War I, kites could offer signaling and observation opportunities. For instance, man-lifting kites helped submarines gain a better view of their above-surface surroundings, raising radio antennae for improved signaling, and even rescuing pilots lost out on the ocean.

Traction kites are much larger because they must lift a person off the ground or water, such as in kite surfing or kite buggying. Smaller kites are normally unable to lift a person off the ground.

#### **Purposes of Kites**

* Kites are widely used around the world in many forms of recreation, or enjoyment. Some examples of kites as recreation are the children and adults alike who can be spotted flying a kite on a windy beach. Kite surfers, surfing waves with the help of a large traction kite may also frequent the same beaches.  Thrill seekers flying in hang-gliders are actually also flying in a very large kite.  
* Kite competitions take place around the world every year.  Competitors may show off trick moves, fly in formation with teammates, or compete for the largest or most artistic kite.  Some types of competitions may also involve grounding opponents’ kites, forcing them downward, or simply cutting their opponents’ lines.There are large festivals around the world every year which mark a special celebration or day by flying a kite.  Some of these festivals are Uttarayan, in India, the Barrilete festival in Guatemala, and the international kite festival in Weifang, China.  Other festivals may have kite fighting competitions as part of the celebration.
* Kites have also had many other types of uses besides recreation, including a long scientific inquiry into weather and flight, as a radio, or as lights. Kites can also be used for aerial photography instead of drones.

Warm-up

#### Tetrahedral Kites

* Alexander Graham Bell was a famous inventor, perhaps best known for inventing the telephone. However, one of his greatest passions was flight. Just as Bell had figured out how to send sound through the air, he now desired a way to send, or fly, a person through the air.

* To test this theory he started to experiment with an existing invention, kites, to create a practical airplane. Alexander saw a kite could carry weight depending on its size and shapes. This brought him to the idea of making a modular kite, which contained many small triangle-shaped kites attached together. Bell knew that the **tetrahedron**, a triangular pyramid, was a very strong yet lightweight shape. He combined **tetrahedrons** into a variety of shapes and structures and covered them with silk.

* The size of this kite could be changed depending on what it was to carry, perhaps a person and even a motor. Alexander Graham Bell built the largest and most complex kites in all sizes and shapes that the world had ever seen. Sadly none of them did carry a human successfully, but Alexander never stopped believing that one day humans would fly. Eventually, his research and work did pass on to future inventions to create the solution of airplanes we enjoy today.

Tetrahedrons are a very strong, rigid, but also lightweight enough of a structure when not filled solid. It is important in kite-flying for kites to be lightweight durable.  In addition, the pyramids could be combined into huge structures, and added comparatively little weight. Making a larger kite allowed Alexander Bell to test the kite flying different objects.

#### Kite Control and Forces

* Kite fliers must successfully overcome gravity in order for their kite to fly. Four **forces** are at work in this process, pushing or pulling on the kite. **Forces** have both a size or amount, and a direction.
* **Lift** is the **force** that pushes upward on the kite. Air is composed of molecules that flow, which makes it a fluid. Just as a rock blocks the flow of water and forces water around it, so air molecules also flow around a curved surface. As the wind blows horizontally and hits a kite at an angle, it generates another **force** called **lift**. **Lift** is perpendicular to the wind and pushes the kite up into the air. The upward push of **lift** must be greater than the downward pull of gravity.
* In kite flying, **drag** and **tension** are two opposing **forces** acting on the kite. **Tension**, or thrust, is the pull that comes from the person pulling on the string. It is balanced by the **drag** or backward push of the wind, and is also known as air resistance. Wind therefore creates two of the **forces** acting on the kite, the backward **drag** and a slight upward **lift**.

Wind generates the **lift force** which pushes kites into the air, as well as the **drag force**, which stabilizes the kite in the air. Birds use the drafts of wind to fly, and the beat of their wings generates their own wind to **lift** off the ground.

Benefits to **collective** transportation include being able to move large amounts of people at a low cost to passengers and less congestion in cities. A drawback is that **collective** transportation may be expensive to maintain and provide at a low cost during non-peak hours. Individual transportation can be beneficial to the environment if people are walking or biking, but could be harmful if many individuals are driving personal cars.

#### Kite Structure and Materials

Although kites have many forms, sizes, and functions, they all have certain similar parts which enable them to generate **lift** and fly.

* The **sail** is the most recognizable part of a kite. **Sails** can be simple and handmade, from any type of paper, or lightweight plastic. **Sails** can also be made from fabrics, both natural types or synthetic ones. The **sail** is important as it is the part of the kite which the wind lifts.
* Kites also need a structure to help them spread out and have the greatest possible surface area. Many kites, such as delta kites and diamond kites owe their structure to very thin and lightweight cylindrical pieces called **spars** that are joined together to make a frame. **Spars** can also be made out of many materials, from natural ones like bamboo or graphite, to man made products such as fiberglass or plastic. Other kites, such as parafoil kites, do not have spars, but depend upon the wind to provide the kite with its structure.
* Another component of kites are the tails. Tails are often beautiful and aesthetic, but they also serve a purpose. Tails increase the drag of the kite which stabilizes it in high winds.

Imagine

#### Facilitation and Collaboration Work

For Create, students can work independently to make a single module of the kite to test in the air. Once each student builds a tetrahedron, group 4 students work together to combine into a 4 cell Sierpinski kite in the [Build](#build) section of this lesson.

Build a tetrahedron

Cut a plastic sheet into a diamond shape

Poke holes into corners of plastic sheet and tape

Insert connectors in holes of plastic sheet

Wrap sheet over two triangle faces of the tetrahedron then click connectors in place

Tape the plastic sheet around the straws of tetrahedron

Complete a drop test

Measure a string to 100 cm (39.40 in) long then trim

Tie the string to each connector using a Lark's knot

Replace a 1-leg connector from the tetrahedron with connector tied to the string

Test fly the single tetrahedron kite

Create

#### Facilitation and Collaboration Work

The Build section of this lesson is designed for students working in pairs or small groups to build 3 additional tetrahedrons with the single tetrahedron built from the Create section. They can assemble into a 4 cellular Sierpinski kite.

Create 3 tetrahedrons

Cut 3 plastic sheets into diamond shapes

Poke holes the corners of the 3 plastic sheets and tape

Insert connectors in holes of each plastic sheet

Wrap sheets around two faces of each tetrahedron and click connectors to secure

Tape the plastic sheet around the straws of each tetrahedron

Place two tetrahedra next to each other then connect

Connect a third tetrahedron

Add fourth tetrahedron on top and connect

Push the legs 1-leg connectors further into the vertices of the tetrahedron to lock

Fold all the 1-leg connectors on the joints to lock

On the 100 cm string, measure 60 cm and mark

Tie a connector at 60 cm mark with a Lark’s knot

Attach the string to the Sierpinski kite

Make a bowline knot at the end of a ball of string

Lock bowline knot from ball of string onto connector

Fly your Sierpinski kite and test the forces at work

Experiment with altitude and lift!

Build

#### Facilitation and Collaborative Work

For this section of the lesson the following questions below can be discussed all together as a class or within each group. You can use the **Flying Kite Forces - Student Journal** asset as a helpful resource to capture ideas and process on the computer or printed ahead of time and distributed.

Reflect

Challenges

References and Extra Resources

STEAM Classroom

United States

Plan and conduct an investigation to provide evidence of the effects of balanced and unbalanced forces on the motion of an object.

NGSS

3-PS2-1

Support an argument that the gravitational force exerted by Earth on objects is directed down.

5-PS2-1

Apply Newton’s Third Law to design a solution to a problem involving the motion of two colliding objects.*

MS-PS2-1

Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.

3-5-ETS1-1

Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.

3-5-ETS1-2

Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.

3-5-ETS1-3

Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

MS-ETS1-1

Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.