2025 4-H Chain Reaction Challenge

Design and build a unique invention that completes a chain reaction of events to feed a pet.

Join the 4-H Chain Reaction Challenge! Form a team, challenge yourself and have fun while tinkering and building a complex invention that links everyday items and simple machines in a chain reaction of fun, chaos and science to feed a pet.

Chain reactions and Rube Goldberg machines link together mechanical “events” to form a chain reaction to complete a simple task in an overly complex way. They are fun to build and use common everyday items and unconventional and whimsical ways.
 

How to Participate

Form a Team: Teams of 2 to 8 youth, ages 8-18. Join 4-H.  Teams can be from 4-H Clubs, SPIN Programs, after-school programs, or homeschool groups.

Find a Mentor: Adult mentors and 4-H volunteers can guide youth and help them plan.

Design and Build: Work as a team to set goals, plan, design and build a chain reaction machine.

Keep a Journal: Teams should keep a Chain Reaction Journal (written or digital) to record ideas, goals, changes, successes, and failures. Required for teams competing at 4-H Clover Corner.
 

Chain Reaction Machine Specifications

• Challenge: Complete the Feed a Pet Challenge in the most creative and fun way.
• Steps: Use a minimum of 10 steps (a step is a transfer of energy from one object to another).
• Footprint: 16 ft² (e.g., 4’ x 4’, 2’ x 8’) and no taller than 5’.
• Support: Must be self-supporting, fixed to a base and/or frame.
• Electrical Components: Are allowed, but only one extension cord may run from the wall to the machine.
• Prohibited Items: No compressed air, hazardous chemicals, flammable materials, explosives, or flames.
• Microcontrollers: Are allowed but must be triggered by a previous step (no timers).
   

Safety Guidelines

• Safety Checks: All components must be deemed safe and will be checked before presentation.
• Avoid: High heat, rapid movement, sharp objects, or other items that may cause harm or injury.
   

Chain Reaction Challenge Showcase

Showcase your Chain Reaction Machine at the 4-H Clover Corner!

Judging Criteria

All teams will have their chain reaction machines judged and recognized for team effort and creativity. Scoring is based on:

Steps: Number of successful steps, 2 pts ea.

Goals: Named and completed learning goals, 2 pts ea.

Journal: Design & build journal, 10 pts.

Creativity: General awesomeness and creativity, up to 10 pts.
 

Judges

Judges are STEaM professionals (Artists, Engineers, Mad Scientists, etc.) who meet with participants to discuss their goals and achievements, certify completion of steps and offer coaching for future inventions. They are the Jedi of Chain Reactions, think of them as part friend, part teacher, part referee, part Yoda.
 

Links

Scoring Rubrics, Inspiration, and Resources can be found on the Chain Reactions Resource page! 
Chain Reactions Resource page

Want a copy of the 2025 4-H Chain Reaction Challenge Rules and Specifications?
Download the 2025 4-H Chain Reaction Challenge PDF

Enroll in 4-H via ZSuite:
ZSuite

Have Questions about enrolling ZSuite?
See our ZSuite Resource Page

If you need an accommodation to participate in our programming, please contact Claes Thelemarck, claes.thelemarck@unh.edu or 603-447-3834, prior to the event. Given ample time, we will make any reasonable effort to meet your needs, including language access services if requested, which will be provided free of charge.