Balloon Cars

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About: The Edgerton Center (http://edgerton.mit.edu/) at the Massachusetts Institute of Technology is a home for experiential learning for students of all ages. For decades before the dawn of the Maker movement, th...

CREATOR(S): Anya Timchenko, Diane Brancazio

Balloon Cars Grades K-8, Engineering, Science

Lesson Overview

In this activity, students design and build a balloon-powered car for play or to compete in a performance challenge. The car design includes a custom 3D printed base, inexpensive toy wheels, and common hardware. Our Balloon Car challenge is an engaging way to practice the Engineering Design Process while learning 3D modeling on Tinkercad. The challenge can also be structured for learning physics principles such as velocity, acceleration, and traction.

This project is structured to follow the Engineering Design Process (EDP), a process that helps designers in any discipline create solutions to problems. While there are many ways that people solve problems, designers often use the EDP because it offers a clear roadmap for them to follow as they work towards a solution.

First, designers Define the challenge they are facing, then Learn more about the problem and Explore existing solutions. It’s tempting to skip these first few steps and head straight into brainstorming, but don’t! When designers take the time to understand the problem clearly, they come up with much better solutions.

The Design phase is where brainstorming happens. Designers brainstorm multiple possible solutions, then develop a few of them into more detailed plans. Encourage your students to plan at least 3 of their potential ideas before choosing a design direction and starting to Create a product based on their design. If they hit any roadblocks trying to create their first design choice, they’ll be able to revisit their alternate design plans and choose a new direction - without starting from scratch.

Designers then take time to Observe their design and see how they can Improve it. We strongly recommend that students have an opportunity for at least 2 Create-Observe-Improve cycles. When students feel they have to “get it right the first time,” they are less willing to take risks and be creative. By repeating the cycle, they have a chance to fix flaws and adopt successful ideas from classmates, and in fact, they’re practicing what professional designers really do.

A good design cycle builds in time for the designer to Reflect on their product and the process of making it, looking for learning habits and insights that will help in future challenges.

When the work is complete, designers are ready to Share. They bring their work into the real world, by posting, publishing, presenting, or exhibiting - or giving or selling if appropriate! - what they’ve made. For students working through a design process, a real audience helps students connect their learning and work experiences to the world outside the classroom. For Makerspaces and Maker projects, in particular, this is hugely important for building confidence in every student and a sense of community among Makers.

To help students work through this process, be sure to build in planned “stops” at each step for students to record their thoughts and progress as they work through product iteration cycles.

Essential Question(s)

  • How can the Engineering Design Process be used to efficiently and effectively create a vehicle to meet a specified challenge?
  • How can a toy balloon car be used to experimentation and understanding of physical principles?

Skills Taught:

  • Engineering Design Process
  • Use of simple hand tools and fasteners
  • Basic physics
  • Basic Prototyping Skills

Time Required: 2 - 3 Hours

Materials Needed:

  • Balloons
  • Flexible PVC Tubing, 3/8” Outside diameter, ¼” Inside diameter, commonly available at hardware stores
  • Rubberbands
  • Plastic Wheels, ~1.5” diameter, with ⅛” diameter hole for the axle, such as http://kelvin.com/front-wheel-blue-yellow/
  • Screws #4 self-tapping screws, pan head, Phillips. 5/8” long
  • Washers, #4 flat
  • Screwdriver, Phillips
  • Balloon inflator
  • Tinkercad
  • 3D printer filament
  • Misc. Arts+Crafts materials (cardstock, plastic sheets, hot glue, markers, etc.)
  • Lightweight objects to carry on the car

Step 1: Define

Context

The Engineering Design Process (EDP) is a respected process for solving engineering and other critical thinking challenges. Students will learn and practice transferable skills involving creativity, communication, collaboration, critical thinking. In this activity, students work individually or in small groups to design and construct a balloon-powered vehicle that meets design criteria designated by the teacher. They use Tinkercad 3D modeling software to create a custom body that includes a base, balloon stem holder, wheel mounts and other optional features for steering, holding items, etc.

This lesson gives students an opportunity to learn about common hardware items as well as technical design and construction techniques. This car is designed to use pre-fab wheels, that are inexpensive and readily available from Technical Education supply companies such as Kelvin.com. This feature reduces 3D printer time and gives the designer a real-world product to coordinate their design. The wheels are mounted to the car base with self-tapping screws which are not tightened down completely, creating a gap for the wheel hubs to roll freely. The flexible PVC tubing used as a balloon stem is another real-world product that students can incorporate in their design.

Challenge

Design a balloon-powered car to complete performance challenges.

Student teams may consider scoring options and plan a strategy to earn points.

Sample Challenge 1 - Targets

Create a target area on the floor either in a linear or bullseye fashion as shown. Cars that reach the outer limits have met the challenge while those that make it to the precise center earn extra recognition. Target features can include point zones or obstacles.

Sample Challenge 2 - Deliver objects

Cars carry and deliver objects such as foam blocks or action figures to a designated target area in a specified amount of time. Cars that carry basic objects have met the challenge while those that carry more complex objects or get there faster earn extra recognition.

The Challenges are set up so there is not 1 winner, but levels which students can try to attain, as they might in sports or martial arts. Student designers can create balloon cars that earn points in different ways, features that enhance their performance and repeatability.

Criteria:

  • Students must build a balloon-powered car that reaches the target (any zone)
  • The car must roll freely, hold a balloon stem securely, and be propelled forward by the deflating balloon
  • The car is assembled correctly using the materials provided/specified by the teacher
  • The car must carry a small item and hold onto it until the car stops (optional, but fun)
  • The car has a logo or text engraved in the bottom (optional, but also fun)

Constraints:

  • The car footprint is less than 10 square inches
  • The car can be printed on the 3D printer in 30 minutes or less
  • No other power source is used to propel the car during the competitions trials

Points:

In the example scoring, Solid zone = 10 points, Super Zone = 12 point, Bullseye = 15 points

Students may be given several trials to reach the target and accumulate points.

Student Product / Learning Goals

Product: Students design, build, and test a balloon-powered car.

Goal: practice an iterative design process to build a vehicle that reliably carries cargo (optional) and reaches the target. Aspects of the car that will need to be designed and redesigned: car body design, wheel assembly, balloon diameter when inflated, angle to the intended path of travel when they first release the car, etc.

Step 2: Learn / Explore

1. Research: Play around with balloons. Attach stems made from PVC tubing and figure out the optimal length for a slow steady release of air from the balloon. Attach the balloon to premade cars or other objects and see how well they are propelled and how the balloon behaves during travel. Choose items to carry as cargo.

2. Collect: Instruct students on how/where to keep notes on their experiments and other things they learned. They may create an “inspiration page” such as a blog, Google Docs, a notebook, poster, etc.

Step 3: Design

1. Design:

Students work together to brainstorm ideas on how to hold cargo and manage the balloon during travel. The design process is most effective when designers create at least 3 different ideas.

Option A: draw designs on how the balloon car will look and/or function. Use paper, whiteboard, drawing apps.

Option B: Build simple models using crafting materials (paper, glue, clay, pipe cleaners, etc.) to show look and/or function

Option C: Let the students play around in Tinkercad to get familiar with the program and make practice models.

2. Direction: Help the students choose a design that fills the criteria of the project, as well as the “Thing” Checklist (this checklist can be found in the Resource section of the Lesson).

Step 4: ​Create

Build the Balloon Car base:

Summary of steps described in the video:

  • Create the Car body using a box sized to: 4” x 2” x ⅛”
  • Create the Wheel Mounts using a Round Roof and size to 0.30” wide “ x 0.125 high x 0.30” long
  • Copy the wheel mount and align to the 4 corners.
  • Make the pilot hole for the screw through the wheel mounts, 0.11” diameter
  • Create the Balloon Stem holder using a cube and a cylinder hole, making sure to measure the tubing to confirm the outside diameter
  • Add a name or decoration on the bottom
  • Add holes or other features to hold the cargo or support the balloon

Balloon Car Assembly video:

  • Assemble the wheels to the base
  • 3D print the base and collect these materials to assemble: 4 wheels, 4 screws, 8 washers (optional), 3” piece of tubing, rubberband, balloon, screwdriver, balloon inflator, craft materials (optional)
  • Use washers on either side of the wheel hub. Tighten the screw so that the wheel rolls freely yet doesn’t wobble.
  • Connect the balloon to the stem with a rubber band

Balloon Car Race:

Experiment with balloon cars and make your own race!

Step 5: ​Observe and Test

1. Play with balloon cars and have a race! Student teams earn points for reaching zones on the target. Encourage students to help each other solve problems so that all teams make it at least to the outer edge of the target.

2. It is recommended that students have an opportunity for at least 2 design-build-improve cycles. When students feel they have to “get it right the first time” they are less willing to take risks and be creative. On the second time through they can fix flaws and adopt successful ideas from classmates.

3. Provide stopping points for the class where students can observe, evaluate, and document their design.

4. Give students a chance to record their thoughts and progress as they work through product iteration cycles.

5. Follow instructions in the Create Step as needed for the next iteration.

Download pdf with possible prompts for Steps 5 and Step 6:

Step 6: ​Reflect

Reflect: After the design and build time is over, have students reflect on the process and product. This reflection is similar to the one in the “Observe, Improve, Iterate” step but now includes reflection on the process as well.

Download pdf with possible prompts for Steps 5 and Step 6:

Step 7: ​Resources

“THING” Checklist: To ensure you get a quality print, go through the list before tinkering and printing.

Meets overall size requirements as specified in the course packet.

Height, Width, Depth, Weight, Volume as specified in the challenge description.

Embossed features stick out no more than 1 mm (.04 in).

Engraved features go in no more than 2 mm (.08 in).

Unsupported features (overhangs) are angled up at least 15⁰ (more is better).

Bridge features have an unsupported span no greater than 12 mm (.5 in).

Wall thicknesses are typically 2 mm (.08 in).

Thin features such as details are no smaller than 1 mm (.08 inch).

Round holes can be at any angle and are greater than 2 mm (.08 in).

Step 8: ​Project Extensions

Possible content explorations

  • Class competition - debrief afterward
  • If students have designed according to the specs of “customer(s),” have them rate vehicles according to customer request, or match the best vehicle to the best customer
  • ELA/Social Studies - if students are reading material about racing, or about characters’ or peoples’ transportation needs, have them create an advertisement about the benefits of their balloon vehicle - e.g. get Ralph Mouse to give up his motorcycle for your balloon car

Modifications

  • Create a balloon-powered sand/snow sled or boat
  • Couple with kinetic sculpture load that moves as the car’s wheels turn

We hope you had fun designing and sharing your Balloon Cars. What did you make? What materials did you use? We want to see! If you did this in a K-12 classroom, what subject was it in?

Send us an email or leave us a comment so we can see what you're making.

Visit our website k12maker.mit.edu to get resources for K-12 teachers:

Maker skills workshops for K-12 educators - Spring, Summer, and Fall

Lists of Tools and Materials and illustrated charts to print and post

Supervision and safety guidelines for shop administrators

Training guides for common tools (including student checklists and refresher guides)

Our Maker Methodology for designing Maker Projects for core curriculum, including sample projects

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