Explore (45 minutes)

1. Divide your students into teams of 3–4. If you have any students that you know are good at making paper airplanes, make sure you split them up. Let each team come up with a team name and write it on their worksheets.

2. Explain that there are a few rules to make sure everyone participates (this is to prevent one experienced student in each team from making and throwing all the planes). After deciding on a final design, each team will make and test four planes. Within each team:

- Every student must participate in making the final four planes. They can do this in an "assembly line" process (one student makes a fold, then passes it to the next student who makes another fold, and so on until the plane is done), or each student can make one plane. (Note for teacher: the assembly line process may be better for teams with varied skill levels. One student can start off with simpler steps like folding the paper in half, and more experienced students can complete the more complex folds).
- Students will take turns throwing the planes for a total of 12 throws (each of the four planes will be thrown three times). For teams of four students, each student will throw three times. For teams of three students, each student will throw four times.

3. Distribute an equal amount of materials to each team. Each team should have at least 12 pieces of paper for testing paper airplane designs. You can decide what quantities to use for any of the optional materials (e.g. one roll of tape, one pair of scissors, four paper clips).

4. Explain how your students will approach this as an engineering problem. Students can follow along on the worksheet, individually or in teams, to identify the criteria and constraints of the problem. You can use this worksheet as a formative assessment to measure their understanding.

- As a customer I want a plane that can fly as far as possible.
- I also want the plane to be reliable. I want to make sure that you did not just have one lucky throw or make one really good plane. To check this, I want your team to build me four planes and throw each plane three times, for a total of 12 throws, and measure how far they go. Then I want you to find the average distance for all the throws.
- Note: your students might not know what "average" means mathematically, or how to calculate it. It is sufficient for the students to have an intuitive understanding. If necessary, you can explain that an average is like a typical value when you have a bunch of numbers. For example, if you lined the whole class up from shortest to tallest, a person of average height would be in the middle. If you have one group of very tall people and one group of very short people, their average height would be about halfway in between (even if there is not one single person whose height is in the middle). Your students can record the distances and you can calculate the average for them.
- I also want a plane that is easy to manufacture. That way, if I decide that I want more planes, I can order them quickly. To check this, I want you to build four new planes in five minutes or less.
- You can only use the materials given to you by the teacher (no asking for more paper).
- Your team will only have 15 minutes to decide on a design.
- After deciding on a design, you will only have five minutes to decide how to build four of the planes. Will everyone on your team build one plane, or will you use an assembly line process?

5. Give the class 15 minutes to experiment with different paper airplane designs and decide on a final design for their teams.

- You can provide the paper airplane instructions sheet as a reference for each team. Point out that these designs are just examples; there is no guarantee that they are the best designs. Remind your students that they are engineers. Engineers design new things and improve existing things all the time. Encourage them to make at least one change or improvement instead of just using designs directly from the instructions.
- Encourage teams to test their designs by throwing the planes. Do not just pick a design because it is someone's favorite or somebody already knows how to make one.
- Keep students aware of the remaining time and make sure each team is on track to agree on a final design before time is up.

6. Give each team five minutes to decide how they will build four copies of their design. Remember that each student must participate in making the planes. They should write their team name and plane number (1–4) on each plane, but this does not count as a step (i.e. they cannot just assign one student to do the writing while everyone else folds). If they choose an "assembly line" process, they should decide who will make which folds. If they decide to have each student make one plane (note: in teams of three, one student will need to make two planes), they should make sure everyone knows how to make a plane by themselves.

7. Give each team five minutes to build four copies of their design.

8. Let each team show the customer the performance of their final design, and record their results on the student worksheet.

- Set up a tape measure on the ground and use it to measure the forward distance the plane travels (see Figure 2) in either inches or centimeters. If you want to avoid dealing with fractions or decimals, round to the nearest whole inch (or centimeter) when recording distances.
- Each of their four planes must be thrown three times, for a total of 12 throws.
- Each student in the team should make three throws (for teams of four) or four throws (for teams of three).
- Calculate the average distance for all 12 throws. Note: if your students have not yet learned how to calculate averages, you can do this step for them (see worksheet for instructions).

Figure 2. How to measure forward distance the plane travels, from where it was thrown to where it lands.