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Building a Balloon Rocket Car

Activity 1: The Skateboard Exercise	Activity 2: Building the Balloon Rocket Car

1. Overview
2. Introduction
3. Activity 1: Skateboard Exercise
4. Activity 2: Building the Balloon Rocket Car
5. Activity Questions
6. Assessment
7. Suggestions for expanding this activity
8. Illinois State and National Learning Standards
   • Early Elementary
   • Late Elementary
   • National Standards
   • Curriculum Standards

Overview

During these hands-on, minds-on activities, students will be asked to build balloon powered rocket cars and complete an exercise using skateboards. These activities demonstrate Newton's Laws of Motion, especially the Third Law, which states that for every action there is an equal and opposite reaction.

The activities are simple and inexpensive, yet they provide endless possiblities for expanding lesson plans and meeting learning standards.

The minimum amount of time needed for this lesson is 90 minutes.

The balloon powered rocket car activity was adapted from National Aeronautic and Space Administration's (NASA) Rockets: Physical Science Teacher's Guide with Activities. Lesson design by university student volunteer, Brooke Dashiels.

Introduction

Introductory Activity

Blow up a balloon, but don't tie it. Ask the students to predict what will happen to the balloon when you let it go. Let it go and watch what happens! Here are some questions to start your students thinking about forces:

• What happened to the size of the balloon when it was released?
• Where did the balloon go when it was released?
• What caused the balloon to move when it was released?
• Did all of the air come out of the balloon?
• What pushed the air out of the balloon?

Additional Discussion and Questions

The Introductory Activity leads into a discussion of Newton's Laws of Motion and how they can be applied to understanding forces, particularly the forces which act on rockets. Here are some sample questions to get the discussion started:

1. What is a force?
2. Is a heavier object easier or harder to move than a lighter object? Why or why not?
3. Why does a rocket need fuel?
4. What is gravity?
5. How does gravity act on a rocket?
6. Why do the boosters fall off of the space shuttle after it is launched?
7. What are some ways scientists can study the forces which act on rockets in the laboratory?
8. If you were building a car would you want to make it light or heavy? Why?

Activity 1: Skateboard Excercise

For the Skateboard Exercise you will need the following materials:

• two skateboards
• two bicycle helmets

Step 1: Helmets

• It is suggested that each participant wears a helmet during the Skateboard Exercise.

Step 2: Using the Skateboard

1. Place the skateboards so that the front of one skateboard touches the front of the other skateboard. Place the skateboards on the floor.
2. One participant stands on the middle of each skateboard.
3. The two participants hold out their hands and touch each other's hands, palm to palm.
4. The two participants then gently push off one another. The skateboards should travel away from each other.

Activity 2: Building the Balloon Rocket Car

To build the Balloon Rocket Car you will need the following tools:

• hammer
• nails
• scissors
• ruler or tape measure
• safety goggles

For each Balloon Rocket Car you will need the following materials:

• four plastic 2 liter or 20 ounce bottle caps
• three straws (one must be bendable)
• two short wooden skewer sticks
• one piece of corrugated cardboard at least 3 by 4 inches
• masking tape
• duct tape
• one balloon
• pencil

Note: If you feel your students might be unfamiliar with the tools and materials, you should review the tools and materials vocabulary with them before assembling the Balloon Rocket Car.

Step 1: Making the Wheels

1. Find a nail that has the same diameter as the skewer stick. Use a hammer and nail to punch a hole into the center of each of the four bottle caps.
   

Step 2: Making the Car Body

1. Use problem solving skills to determine and cut out the rocket car body out of corrugated cardboard.
2. Estimate the width of the rocket car body by looking at the length of the skewers, straws, and bottle caps. (Note: The rocket car body does not necessarily need to be a particular shape.)
3. Estimate the length of the rocket car body by taking into consideration that the participants will need to be able to blow up the balloon through the straw.
   

Step 3: Designing the Axles

1. Use problem solving skills to determine and cut the straws for the front and rear axles. (Note: the length of the straws should be approximately the same size as the width of the cardboard.)
   
2. Use masking tape to tape the straws to the underside of the body.
   

Step 4: Attaching the Wheels

1. Thread the skewer through the straw.
2. Thread one bottle cap onto each end of the skewer.
   
3. Repeat this procedure for each axle.
   

Step 5: Making and Attaching the Propulsion System

1. Blow up a balloon three or four times to stretch it out.
2. Attach the balloon to the bendy end of the straw with duct tape.
3. Masking tape the straw with the attached balloon perpendicular to the axles on the top of the car body. (Note: The straw must extend beyond the rocket car body on both ends so that the participant can blow up the balloon through the straw and also so that the balloon can expand without hindering the movement of the wheels.)
   
   
   

Step 6: Using the Balloon Rocket Car

1. Blow up the balloon through the straw.
2. Once the balloon is blown up, pinch the straw closed.
3. Put the rocket car on the ground and release the straw.
4. Watch it go!
   

Activity Questions

Part 1: Skateboard Exercise

1. Make a prediction about the distance your skateboard and your partner's skateboard will go when you push off each other.
2. Measure the distance your skateboard and your partner's skateboard went when you pushed off each other.
3. Describe what happened when you and your partner stood on the skateboards and pushed off each other.
4. Describe the similarities and differences between how the Skateboard Exercise works and what happened to the balloon in the Introductory Activity.
5. On the back of this paper, draw a picture of the direction each skateboard moved and use arrows to show the forces which act on the skateboards when they are moving.

Part 2: Balloon Rocket Car Activity

After building the Balloon Rocket Car, blow the balloon up through the straw. Pinch the straw so the air can't get out.

1. Make a prediction about how far the car will go when you release it then put the car on the floor and let it go!
2. Measure the actual distance the car went when you released it.
3. Describe what happened to the balloon when you released the car.
4. Describe the similarities and differences between how the rocket car works and what happened to the balloon in the Introductory Activity.
5. On the back of this paper, draw a picture of the car, label the parts and use arrows to show the forces which act on the car when it is moving.

Extra Credit

1. Explain what would happen if you put rocks, or other heavy objects on the car body.
2. Describe the similarities and differences between the rocket car activity and the skateboard exercise.

Assessment

Our assessment methods were the same for Illinois and National Standards.

Our assessment methods were the same and for Early and late Elementary School students. What changed was the level of the questions asked and the discussion.

We used informal assessment methods in the form of verbal questions and discussion. Formal methods of assessment included drawings, and written answers to questions, and the development of articles for the BOAST Kids Newsletter.

During the Lesson

The participants used inquiry strategies to successfully build the balloon rocket car. Then they tested the device and reported on its use. Throughout the lesson, the participants discussed Newton's Third Law.

After building the balloon rocket car, the participants were trying their cars out in the hallway, where there is a ramp with a slight incline. The participants tried their cars out on the ramp. The result was that the cars would go down the ramp, but they would not go up the ramp. One of the participants thought that his car might go up the ramp if the car had an additional balloon to give it more power. He put another balloon on a straw and attached both of the straws to the top of the car body. When he released the car with the two balloons at the bottom of the ramp, it went up. This action, by a kindergarten student, was followed by many participants adding additional balloons to their cars.

While experimenting with the skateboard, it seems that most of the children were able to understand one of the most basic concepts presented in the lesson: Newton's Third Law of Motion which applies to the inertia of an object, or as one child said, "Big stuff is harder to move." In one instance, a child was on one skateboard while a university student volunteer was on the other. After the two had pushed off each other a few times, and the child had traveled quite a ways each time, the volunteer asked her why she moved so much and he didn't. She replied, "Because big stuff is harder to move!" This observation by a third grader was especially good because prior to the lesson, most children thought that one person would move further than the other because the bigger person was pushing harder.

At the Conclusion of the Lesson

At the conclusion of the lesson, a discussion was held to determine the level of participant understanding concerning the lesson introduction and activities. Some of the discussion centered around the questions asked in Part 1 and in Part 2 of the worksheet.

Other questions centered around Newton's Third Law of Motion and the Lesson Introduction and activities. Some of these questions were:

• Describe the forces which acted on the balloon in the introductory activity.
• How does Newton's Third Law explain what happened to the balloon in the introductory activity?
• How does Newton's Third Law explain how the Rocket Car works?
• How does Newton's Third Law explain what happened to the participants during the Skateboard Exercise?

Each of the children who participated in the lesson was able to answer these questions at his/her own level.

Suggestions for expanding this activity

The Skateboard Exercise

• Repeat the exercise and have the students change partners so that they can determine whether changes in mass, height, gender, or other variables result in changes in the distance travelled by the skateboards.
• Repeat the exercise using different kinds of skateboards to see if this changes the distance travelled by the skateboards.

The Balloon Rocket Car Activity

Try these variations on building the Balloon Rocket Car:

• Build several cars using a different shaped body for each one.
• Use other materials to build the rocket car body. For example styrofoam, wood, or various thicknesses of cardboard.
• Use other materials for the wheels such as styrofoam, cardboard circles, milk bottle caps...
• Try attaching the wheels in a different way. For example, pin the wheels directly to the side of the car body.
• Try blowing the balloon up different amounts.
• Try different balloons, small, large, round, or cylindrical.
• Try adding more than one balloon to the car.

Try these variations on using the Balloon Rocket Car:

• Try running the rocket car on different surfaces such as a tile floor, rug, sidewalk, dirt or snow.
• Try running the rocket car on slopes.

Illinois Learning Standards that Apply to this Lesson

The following standards are from the Illinois Learning Standards, adopted by the Illinois State Board of Education on July 25, 1997. Take a look at the complete Illinois Learning Standards for Science, Mathematics, and English/Language Arts.

Early Elementary

Late Elementary

National Science Education Standards that Apply to this Lesson

This is one lesson in a unit on space. During the unit participants learned about the solar system and man-made space craft. This particular lesson's focus is the application of Newton's Laws of Motion, especially the Third Law, to rockets.

Take a look at the National Science Education Standards.

Curriculum Standards that Apply to this Lesson

Take a look at the complete curriculum standards of the National Council of Teachers of Mathematics.