Paper Rockets to Learn the Scientific Method

Background Information for Teachers

This lesson is designed to guide your students through the steps of the scientific method (Figure 1) using a fun, hands-on project: paper rockets. You can read about the scientific method, or assign your students to read about it, in much more detail in this guide.

Image Credit: created by Amy Cowen for Science Buddies / Science Buddies

The scientific method starts with a question, then background research is conducted to try to answer that question. If you want to find evidence for an answer or an answer itself then you construct a hypothesis and test that hypothesis in an experiment. If the experiment works and the data is analyzed you can either prove or disprove your hypothesis. If your hypothesis is disproved, then you can go back with the new information gained and create a new hypothesis to start the scientific process over again.

Figure 1. Steps of the scientific method.

Your students will build small rockets out of paper and tape. The rocket fits onto a straw, and can be launched by blowing into the straw (Figure 2).

Image Credit: Ben Finio, Science Buddies / Science Buddies
Figure 2. Paper rocket.

Before doing this lesson with your students, it will help if you are familiar with some of the basic science concepts behind the paper rocket's flight. Depending on what variables students choose to investigate for their projects, they may need to do more research about some of these concepts. The references in the Additional Background section provide an overview of these concepts. Here are some potential points of confusion students may have:

• The directions of thrust, lift, drag, and weight. Lift and drag are defined based on the direction of the rocket's movement relative to the air. Drag is opposite the direction of motion, and lift is perpendicular to the direction of motion. Normally, this does not cause any confusion because we think about objects that fly horizontally (like a paper airplane), so lift points up. However, if a rocket is launched vertically, then lift points sideways and not up (Figure 3).
• Real rockets provide continuous thrust by burning fuel, which is expelled out the back end of the rocket. According to Newton's third law of motion (for every action, there is an equal and opposite reaction), since the fuel is pushed out the back of the rocket, the rocket must be pushed forward. This concept also applies to certain toy rockets, like model rockets, water bottle rockets, and baking soda/vinegar rockets, all of which expel some sort of fuel. However, the paper rockets in this project do not carry any fuel. They are propelled forward by one initial puff of air from the straw, but after that, do not produce any thrust on their own.
• The rockets have fins that, at first glance, might seem like they act like wings and generate lift if you launch the rocket horizontally. However, the fins are very small and their primary purpose is to keep the rocket stable and prevent it from tumbling—not to provide lift. See the "Rocket aerodynamics" reference from Science Learning Hub for more details.

Image Credit: NASA / Public Domain

The thrust of the rocket comes from the gas being expelled and acts as a force that pushes the rocket upwards. The weight of the rocket has a force that pulls the rest of the rocket straight towards the ground. Drag is similar to friction and will act as a force opposite of the rockets direction of travel, and lift created by the air passing over the rocket body will create a force perpendicular to the thrust force.

Figure 3. The directions of lift, drag, weight, and thrust acting on a rocket (image credit NASA).

Additional Background Links

• Steps of the Scientific Method, Science Buddies
• What Is a Rocket?, NASA
• How Rockets Work, NASA
• Rocket Aerodynamics, NASA
• Rocket aerodynamics, Science Learning Hub

Prep Work (5 minutes)

• Build one rocket yourself so you have it ready as a demonstration for the class. See this video for instructions.
• Search online for some pictures and videos of real rockets that you can show your students.

Engage (10 minutes)

1. Show the class some pictures and videos of real rockets.
2. Demonstrate your paper rocket for the class. Explain that the paper rocket is a model, and sometimes scientists use models to represent real systems. In this case, paper rockets are useful because it would not be practical for us to build and test real rockets in a classroom. The paper rockets will allow us to do experiments to answer questions we have about rockets.

Explore (90 minutes)

Guide your class through the steps of the scientific method using the paper rockets as an example. The student worksheet can be used as a guide. You may choose to assign some of these steps as homework instead of doing them in class.

1. Ask a Question. Based on the pictures/videos of real rockets they have seen, and the demonstration of the paper rocket, each student should come up with a question to test with an experiment using the paper rockets. Here are some examples of possible questions:
   • How does the length of a rocket affect the distance it flies when launched horizontally?
   • How does the shape of the nose cone affect the rocket's maximum height?
   • How does the location of the fins affect the rocket's stability?

   Some questions might not be possible to answer with the paper rocket models. For example, "Which rocket fuel works best?" is not feasible since these rockets do not use fuel.

2. Do Background Research. Students should think about aspects of the paper rockets that relate to their question, and do related background research about real rockets.
3. Construct a Hypothesis. Students will need to identify the independent, dependent, and control variables in their experiment. They should make a hypothesis with a scientific explanation for how the dependent variable is affected by the independent variable, and make a specific prediction about how changing the independent variable will change the depending variable. For example, "Longer rockets are more streamlined, so if I make the rocket's body longer, then it will fly farther."
4. Test with an Experiment. Students should carefully list all the materials required and write out the procedure they will follow before they start their experiments. They need to figure out how they will take measurements, how they will keep their control variables constant, how many trials they will do, etc. Important: for sanitary reasons, students should not share straws. Make sure each student uses their own straw.

Reflect (90 minutes)

1. Analyze Data and Draw Conclusions. Students should analyze and graph their data using grade-level appropriate math (e.g. calculating averages) to determine the experimental relationship between their independent and dependent variables. Does this relationship support their hypothesis? Remind them that it is OK if their results do not match their prediction, as long as they attempt to explain what happened.
2. Communicate results. You can decide how you want students to communicate about their experiment. Options include just turning in their worksheet, a written report, an oral presentation, and/or a poster. Emphasize that students should explain the entire process they went through, starting with the question they asked—not just the quantitative results of their experiment.

Assess

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