Chain Reaction Challenge Part 1

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

Session ROLES:

🐙 = Site Coordinator

🦉= Mentor


Notes for Site Coordinators and Mentors:

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

  2. This session guide provides a detailed outline for part 1 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 1 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





Prerequisite Knowledge:

Intro to littleBits

Invention Cycle



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 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.

    • Place a variety of construction materials and tools in a central location in the room.

  • The Chain Reaction Challenge is made up of two ~2hr sessions. Note that girls will need to be able to store their in-progress inventions in between sessions 1 & 2.

  • This challenge can be done individually or in small groups (2–3 girls). Decide beforehand what makes the most sense for your site.

    • For an advanced challenge, have the whole group collaborate to invent a massive contraption!

  • For this challenge, we suggest handing out the kits during the CREATE phase (after the ideation activities) to keep girls focused on initial instructions.


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


Meet Up

5 min


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


Check in with your mentee to make sure she signed up with (previously

Take turns asking each other questions. Example prompts:

  • DIY: Discuss what your mentee explored on since last session. What topics did they find interesting and why? Did they participate in any challenges. If possible, take a look together on

  • What's one thing you created or invented this week?



10 min


Introduce the session objectives and the concept behind the session:

“Rube Goldberg was a cartoonist who liked to draw really complicated solutions to very simple problems. For example, to turn the page of a book, you might roll a ball down a ramp that hits a box. Then the box falls over and scares a hamster that starts running on its wheel, that winds up a string that turns the page. In this challenge, you’re going to design your own multi-step machines. Before you start inventing, there are two important rules: 1) Once you start your machine, it needs to be able to run without any help from you. Each step must be triggered automatically by the step before it, and 2) Your machine should have at least two steps (bonus points if you can create more!)”

Share videos and/or cartoons of Rube Goldberg machines to provide context and inspiration.

Most design challenges focus on how life can be made easier by an invention. This challenge is a fun exploration in the opposite direction. How complicated can we make a very simple task? To this end, you may work in a little absurdity and whimsy.

Before jumping into the challenge, provide a quick review of the Invention Cycle framework. Ask girls to share lessons learned about Bits, the invention process and things they enjoyed or struggled with from previous challenges.

Goals for Chain Reaction Challenge PART 1

  • Brainstorm ideas for a multi-step machine that completes a task

  • Experiment with simple machines

  • Explore interactions with different Bits and materials

  • Choose a direction to work towards

  • Create a sketch of the invention idea

  • Start creating a prototype



10 min

🦉MENTORS Review session inspiration videoS and prompts with girls 

Rube Goldberg was a cartoonist, engineer, and inventor who created chain reaction contraptions to perform simple tasks. He inspired many inventor’s to make their own Rube Goldberg machines. Here are some examples:


Joseph Hersher: An easy way to be more productive at lunch time

OK Go - Giant Rube Goldberg

Rube Goldberg Machines made with littleBits


Six Rube Goldberg Machines



80 min


Facilitate the CREATE activities with mentees.


During the CREATE 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.

Change Reaction Challenge

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



  • Prompt girls to create a list of everyday activities that only take one step. For example, dropping a can in the recycling bin, flipping on a light switch or opening a book. Record these ideas on a piece of paper to refer to as you build.

  • Come up with 5-10 ideas and write them down. No idea is a bad idea!


Choose an Idea

  • After making a list of 5–10 ideas, have girls choose the everyday activity that they want to accomplish. It could be the idea that sounds the most fun to solve or is the most accessible at your location. 

  • You can always come back to the other ideas later.


Explore your Bits and Accessories

  • Instruct girls to look through their available Bits and accessories to see how they could (or couldn’t) be combined to help solve your problem. For example, how could a servo trigger a slide dimmer? How could a buzzer trigger a sound sensor? Could the latch play a role? 

  • Test out different Bit combinations to see you can achieve the interactions you want. 

  • Use the Snap the Gap STEM Kit Bit Index for more info about each Bit.


Experiment with Materials to Create Simple Machines

How could other materials (e.g. books, cardboard, cups) serve as triggers? Here is some inspiration. Get started by watching these intro videos:




Build two simple inclined planes. You can use cardboard or found objects. Test rolling a small ball down the ramps. Which ramp is faster?


Create a marble run by building a series of book ramps. See how many levels you can create.



Build a lever out of cardboard or found materials. Place an object on one end of the lever and experiment with what weight you need to cause it to tip.


Create a marble run that uses both inclined planes AND levers. Try to come up with as many actions as possible for your ball to move through.

*You can save parts and pieces from your experiments to use in the next session when you build a prototype for your chain reaction contraption


Sketch Out Your Chain Reaction Contraption

  • What task are you trying to complete?

  • Label what Bits and materials do you plan to use (*Note: your machine must use littleBits)

  • How do you plan to combine different elements?

  • How does it work?

  • What do you want your invention to look like?



Make a plan for next session

  • In the next session, girls will test, improve, and then demonstrate their chain reaction contractions for the group (or as one giant machine).

  • Discuss with your mentee if there are any special materials they want to use for their invention. 

  • Make a plan to bring these materials for next session if you don’t have them in this session. Perhaps you can divide and conquer - you can bring a few things and so can your mentee.



5 Min


Reflect with your mentee: “What is one new thing that you learned during this challenge?”



10 Min

Wrap Up


  • Discuss with your mentee if there are any special materials they want to use for their final invention. Make a plan to bring these materials for next session. Perhaps you can divide and conquer - you can bring a few things and so can your mentee.

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

  • Place all Bits & Accessories that you are not using back in the box.

  • Store the sketch in the kit box as well so you can reference it next time.


  • Find a safe place to store girls’ prototypes until the next session.

  • Store kits away for next time.

  • Announce plan for next session:

    • Create a prototype of a machine that combines littleBits and other materials to complete a task

    • Test your prototype

    • Iterate and make updates to the invention

    • Share with the group how your machine completes a task


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.