Example units · Design

Strawbots

IB MYPDesignGrades 6–8

Explore the unit · illustrative introduction

Strawbot

StrawbotCompare a centred weight with an off-centre weight. Predict which will shake the frame. Illustration by April Zhu and Tolga Cohce. MIT licensed.
Explore Strawbot

Scrub slowly to compare. Actual movement also depends on the legs and surface.

Compare a centred weight with an off-centre weight. Predict which will shake the frame.

Students explore how joints work by investigating real joints in the human body and designing their own strawbot mechanisms. They build an initial strawbot with straws and DC motors, then plan an improved version that incorporates 3D-printed parts. Using orthographic drawing, students design a custom part in Tinkercad and send it to a 3D printer. After assembly, they test their finished strawbots in races and evaluate how well their design choices worked. Throughout, students document their process and reasoning, learning how joints enable movement and how different materials serve different purposes in mechanical design.

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What students do

  • Make & document35%
  • Read29%
  • Write17%
  • Design chain5%
  • Check understanding5%
  • Explore & simulate5%
  • Hand in4%

IB MYP criteria

  • AInquiring and Analysing
  • BDeveloping Ideas
  • CCreating the Solution
  • DEvaluating

Tools students use

The green ones are free to try now — no account.

The lessons

  1. A paper cut-out man looking through a magnifying glass at sticky notes of questions

    Discover

    Find out what's really going on.

  2. 1. Joints in the Real World

    6 activities

    1. What is a Joint?Read the three cards below.Read
    2. Joint or Not? Warm-up SortSort each item into the correct column: Natural Joint, Man-made Joint, or Not a Joint.Check understanding
    3. Types of Synovial Joints – Anatomy OverviewRead
    4. Joint Image Collection & AnnotationFind at least four images of joints: at least TWO natural joints (e.g. in animals or plants) and at least TWO man-made joints (e.g. in buildings, machines, or …Make & document
    5. Joints Research QuestionsAnswer each question using what you found during your research.Write
    6. Lesson Reflection: Joints ResearchAnswer the three reflection prompts honestly.Write

  3. 2. Playing with Joints

    6 activities

    1. What Makes a Joint?Read the three cards below.Read
    2. Joint or Not a Joint?Click each item, then click the column where it belongs.Check understanding
    3. Investigate Your JointsUsing the straws and connectors on your table, test at least two different ways of joining straws before you start your strawbot.Write
    4. Build & Document Your StrawbotBuild your strawbot using straws and at least one type of joint you tested.Make & document
    5. Annotate Your StrawbotUpload your strawbot photo (or use the one you just took).Make & document
    6. Document Your ProcessAnswer the three questions below.Write
  4. A paper cut-out man leaning on an empty square frame

    Define

    Say exactly what you're solving.

  5. 3. Design your advanced Strawbot

    Assessment

    5 activities

    1. Your taskYou've researched how joints work, built a basic strawbot, and seen what it can and can't do.Read
    2. Design specificationWrite 2-3 success criteria.Write
    3. Your range of ideasPhotos of your 3+ concept sketches.Make & document
    4. How this is markedRead
    5. Hand it inHand in
  6. A paper cut-out girl holding a clear phone mock-up over a sketchbook

    Prototype

    Make it real, roughly, then properly.

  7. 4. Build V1

    Assessment

    6 activities

    1. Your taskWhat you're making Working with your partner, you will select one of your design ideas and build a first physical prototype — Version 1 (V1).Read
    2. Image of the design you choseUpload your work.Make & document
    3. Process logLog what you made today — a photo and what you did.Make & document
    4. A short reflectionIn 2-3 sentences, what V1 achieves, what it doesn't, and what you would change in a next versionWrite
    5. How this is markedRead
    6. Hand it inHand in

  8. 5. V2 Research

    4 activities

    1. Key wordsRead
    2. What 3D-printed parts can do that straw cannotLook at the three cards below.Read
    3. Example sortSort each example into the right column.Check understanding
    4. Image annotateadd 1-2 annotations per image about a)what about the image inspired you and b)anything else that stood outMake & document
  9. A paper cut-out man looking through a magnifying glass at sticky notes of questions

    Discover

    Find out what's really going on.

  10. 6. Orthographic Drawing practice

    4 activities

    1. Key wordsRead
    2. The Three Rules of Orthographic DrawingLook at each rule on the cards below.Try the Orthographic drawing practice free ↗Read
    3. Example sortRead each drawing fragment below.Check understanding
    4. Orthographic Drawing DrillChoose your difficulty level using the tier slider.Try the Orthographic drawing practice free ↗Explore & simulate
  11. A paper cut-out man leaning on an empty square frame

    Define

    Say exactly what you're solving.

  12. 7. Design the part you'll 3D print

    Assessment

    6 activities

    1. Your taskWhat you're making You will design and 3D print an original part, documenting the full journey — from brief and research through planning, sketching, drawing, …Try the Orthographic drawing practice free ↗Read
    2. Concept Drawings with AnnotationsUpload 2–3 designs. On each, drop a pin on a specific part and write one note about what works (or doesn't).Make & document
    3. Which one you choseWhich concept did you choose?Write
    4. Orthographic drawingYour chosen idea completed on grid paper, drawn to a 1:1 scale, showing the top, front, and side views, with all key dimensions labelled.Try the Orthographic drawing practice free ↗Make & document
    5. How this is markedRead
    6. Hand it inHand in
  13. A paper cut-out man looking through a magnifying glass at sticky notes of questions

    Discover

    Find out what's really going on.

  14. 8. Log into Tinkercad and do tutorials

    3 activities

    1. Copy this class code: (hidden)You'll use it in the next stepRead
    2. Log into Tinkercad using the class codeRead
    3. Tinkercad Tutorials (Beginner)Read
  15. A paper cut-out girl holding a clear phone mock-up over a sketchbook

    Prototype

    Make it real, roughly, then properly.

  16. 9. Make your piece in Tinkercad and export

    2 activities

    1. Make your piece in TinkercadNow that you have designed your piece and have Tinkercad skills, model your piece in Tinkercad The resources below include .stl files that you can import into …Read
    2. Strawbot Unit FilesRead

  17. 10. 3D print your piece

    7 activities

    1. Follow the instructions to printExport from TinkercadRead
    2. 2. Select everything and .stl formatRead
    3. 3. Go to Fabrication menu at the top then 'New Submission'Read
    4. 4. select 3D PrinterRead
    5. ActivityUpload your .stl file from Tinkercad to this space and then hit the 'upload and scan' buttonRead
    6. 6. Once it scans OK you can then submitRead
    7. InstructionsRead
  18. A paper cut-out woman timing a cardboard car down a ramp with a stopwatch

    Test

    Try it. Find what breaks. Fix it.

  19. 11. test and evaluate

    Assessment

    6 activities

    1. Your taskWhat you're making You are testing your strawbot and writing an evaluation of how well it works.Read
    2. TestsRun your strawbot at least three times.Design chain
    3. Image annotateUpload a clear photo of your built strawbot.Make & document
    4. Written answerWrite your evaluation in three sections: What succeeded.Write
    5. How this is markedRead
    6. Hand it inHand in

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Students work through each lesson with the thinking tools built in, and build a portfolio as they go.

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