Chain Reaction Challenge Part 2

Invent a wacky multi-step machine to complete a simple task

Session ROLES:

🐙 = Site Coordinator

🦉= Mentor

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Notes for Site Coordinators and Mentors:

  1. This challenge is structured as two individual 2hr sessions. This session is Part 2 of the Chain Reaction Challenge.

  2. This session guide provides a detailed outline for part 2 of the Chain Reaction Challenge, but feel free to improvise or put your own spin to things. If you have an idea for a challenge or prompt that will get girls excited, go for it! If something is not working well, change course and experiment another path forward.  If you do change things up, we would love to hear what has been successful for you!  

Get Social!

📷 We love to see invention in action! Take photos/videos of your session and tag us on social with the hashtag #snapthegap. *Please make sure you have sharing authorization from parents and your affiliated organization before posting.


Session Overview

The Chain Reaction Challenge is structured as two individual 2hr sessions. This session is Part 2 of the Chain Reaction Challenge.

Inspired by Rube Goldberg, this session challenges girls to explore a variety of mechanical interactions and solve a very simple problem in a wacky and complex way.

Girls will brainstorm ideas and then use the littleBits Invention Cycle to perform a simple task with a chain reaction contraption. Then they will build and test multiple prototypes of their favorite idea. At the close of the session, girls will create videos or cartoons of their chain reaction contraption in action.

As an added challenge, combine multiple group’s contraptions together for a mega reaction!


Session Details




2 hours






Bits + Accessories:

Snap the Gap STEM Kit


Mentors will need to bring a connected device (phone, tablet, or computer) to access instructional videos

Recycled Materials:

Ex: cardboard, cereal boxes, plastic bottles, etc. You can work with girls and mentors to collectively bring these supplies in as needed.



Other Materials:

Extra 9V batteries


Small balls (like marbles, bouncy balls, round beads)

Pen/Pencil & Paper




Theme: Simple Machines

Objectives: By the end of the Chain Reaction Contraption Challenge, girls will be able to:

  • Brainstorm ideas for meeting the designated challenge

  • Create and test a circuit containing a power source, inputs, outputs, and wires

  • Construct a prototype of an invention using Bits and other materials

  • Test their prototypes and make improvements

  • Demonstrate their ability to Create, Play, Remix and Share an invention through the littleBits Invention Cycle

  • Summarize their process and demonstrate how their chain reaction contraption completes a simple task in a complex way.


Set Up


  • Make sure all the supplies for this session are prepped and ready to go. Discuss with mentors if you need help gathering recycled materials.

  • This is part 2 of the Chain Reaction Challenge. Girls should have sketches of their ideas and the simple machine experiments from the previous session.

  • If girls are participating in groups, be sure that they keep track of the Bits and accessories they use so everyone has a full set at the end of the challenge.


  • Make sure to bring a charged connected device (phone, iPad, or computer) to access instructional videos during the session.

  • If you discussed adding additional materials with your mentee in the previous session, please make sure to bring them for this session.


Meet Up

5 min


Take attendance and make sure mentors and girls are paired off.


Discuss with your mentee:

  • How was your week?

  • Discuss with girls whether they had any new ideas for their Chain Reaction contraption since last session

  • Take a look at any additional materials you each brought for the session



5 min


Today we will pick up where we left off last time.

Goals for Changemaker Challenge Part 2: 

  • Create a prototype that combines littleBits and simple machines to complete a task

  • Test your prototype

  • Iterate and make updates to the invention

  • Share with the group how your machine completes a task

Before jumping into the challenge, provide a quick review of the Invention Cycle framework.



30 min

Chain Reaction Contraption Challenge P2

Invent a wacky multi-step machine to complete a simple task


Facilitate the CREATE, PLAY, and REMIX activities with mentees.


During the CREATE, PLAY, and REMIX activities, float around the room and observe/help out where needed. You will also monitor the time and announce when the group should come together to share.

Create a prototype of your machine that combines Bits and your simple machine experiments

  • Use your sketch and any simple machine prototypes you experimented with last session.

  • A prototype is a simple model that lets you test out your idea!

  • Don’t worry about getting everything right on the first try! The important thing is to just get started and experiment. Building a physical model of your idea makes it easier to share with others and collect feedback on your design.

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10 min

Test out your prototype

  • Once the prototypes have been constructed, girls should test the steps of their contraption to see if it works. Does it complete the task?

  • Getting all of the moving pieces to work together is going to be a challenge; failure is part of the process. Encourage girls to try running the contraption a few times, doing initial adjustments on angles, connections and materials.

  • Take notes about what works and what doesn’t. You can make changes in the next version.



30 min

Now’s your chance to experiment with fixes and improvements

  • Could adding a new Bit add important features? 

  • Would craft materials make it stronger or give it a new look? 

Test the invention again after a few improvements have been made 

  • Work with another person -  a classmate, friend, or your mentor. If possible, try to find the type of person you’re designing it for. 

  • Ask the person you are working with what their favorite features are and what suggestions they have to make it better. 

  • Use their feedback to create an even better version of your invention. 

As your make changes to your invention, make sure you are documenting your prototypes are changing and the results (good and bad).

Continue to test and remix until the prototype it is in a state that the girls are happy with the result or until the allotted time runs out. Ask girls to explain their remix choices and the resulting change in functionality and outcomes.

*If doing the whole group challenge, now is the time to combine contraptions and work together to ensure that each invention is triggering the next



25 Min

For the showcase, girls will demonstrate their Chain Reaction Contraptions in action.

🦉MENTORS help girls prep for their presentation

Prep: Girls should be prepared to discuss the following information

  • What task does it complete?

  • Important features - i.e. levers, ramps, sensors

  • What Bits and materials were used?

  • Favorite part about building the invention

  • What did you learn by building your invention?

🐙SITE COORDINATORS Gather girls together to share their inventions


  • Each girl (or group) will have about 5 minutes to demonstrate how their Chain Reaction Contraption works

  • Snap photos of the final invention!

  • During the presentation, mentors can also help prompt girls with questions

  • Encourage girls and mentors to ask questions after the presentation

*If your site is creating a mega Chain Reaction Contraption, take a video of each step of the machine along the way!

Give girls a preview of the next session:

  • Next week, we will begin our next open challenge!



5 Min


Reflect with your mentee:

  • How do engineers and designers they make sure their projects work?  

  • What happens if the project doesn’t work?

  • How do they get better at the work they do?



10 Min

Wrap Up


  • Make sure girls power off the Power Bit and disconnect the battery.

  • Deconstruct inventions: Make sure to take pictures of what girls have made. Girls may take home the paper portion of their invention if they like.

  • Clean up: Make sure girls have all the parts shown on the side of the box and put them away in the kit. If girls were participating in groups, be sure that everyone has a full set at the end of the challenge.


  • Announce Super Important Homework: Before next session, girls should go on, select a topic that sounds interesting, participate in 1 challenge, and upload to the community. You will discuss it next time!

  • Store kits away for next time


Log Your Session

Tell Us How It Went

Your feedback is essential to help us improve the program!



After the session, please fill out the Session Feedback Form

Get Social! 

📷 We love to see invention in action! Take photos/videos of your session and tag us on social with the hashtag #snapthegap. *Please make sure you have sharing authorization from parents and your affiliated organization before posting.