2 Engineering Mystery Bag Challenges for Kids

Mystery Bag Engineering Challenges for Kids

If you are a fan of the hit TV reality competition, Masterchef, then you would be familiar with the concept of the mystery box challenge – it’s actually my favourite part of the show! For those who don’t know, the contestants are each presented with a box of identical, mystery ingredients from which they are required to create a mouthwatering dish. They don’t have to use every ingredient in the box but apart from a few, very basic pantry staples, what they discover in the box is pretty much it. It’s fun to see the dishes created by the talented and very creative contestants.

Taking this concept and applying it to children, learning and the great ideas children have, I recently put together two Mystery Bag Engineering Challenges for a group of great kids (aged between 6 and 12 years of age) to get creative with. The children all had lots of fun and it was fascinating to see how each approached their challenge and the use of materials.

2 Engineering Mystery Bag Challenges for Kids

CHALLENGE ONE: The Pom Pom Launcher

Mystery bag #1 challenged the children to make a Pom Pom Launcher;

Pom Pom Launcher Challenge

The materials available in the mystery bag were;

Pom Pom Launcher mystery bag materials

  • Pom poms
  • Large index cards
  • Paper drinking cups
  • Tape
  • Drinking straws
  • Popsticks
  • Rubber bands
  • String
  • Paper clips


Pom pom launcher

Pom pom launcher in action

Pom Pom Launcher Mystery Bag Challenge #2 firing a long way

Pom Pom Launcher Mystery Bag Challenge The Cup Launcher

Pom pom launcher bow and arrow style

Pom pom launcher prototype

CHALLENGE TWO: The Free Standing Marble Run

Mystery bag #2 challenged the children to make a Marble Run;

Marble Run

The materials available in the mystery bag were;

Marble run mystery bag materials

  • Marbles
  • Tape
  • A cardboard tube
  • Large index cards
  • Large popsticks
  • Paper clips


Marble run mystery bag planning

Marble run mystery bag challenge

Marble run mystery bag challenge #2 modifications

Marble run mystery bag challenge #2

Didn’t they all do well!

As they were completing their mystery bag task the children were all developing and applying skills and knowledge associated with;

  • Creative thinking
  • Planning
  • Problem solving
  • Spatial relationships
  • Measurement
  • Kinetic energy
  • Trial and error
  • Task perseverance
  • Emotional control
  • A sense of achievement
  • Fine and gross motor skills

All while they were having great fun!

With this type of challenge, you can adapt each task by simplifying or extending the difficulty of the challenge – see the extension idea on the Marble Run task card above as an example. If you have never tried this type of activity with your children before, you might find the tips from this post – 5 Construction Challenges for Kids with Big Ideas, helpful.

Engineering mystery bag challenges for kids

Have children who love to build? Be sure to check out our collection of the best building kits for kids and our list of 21 awesome Lego books for kids.


  1. Oh I love this so much! Thanks for the wonderful ideas to get me kiddos innovating. Can’t wait to try it!

  2. Ph my gosh, so many awesome ideas! Love it!

  3. I love seeing kids getting creative. What a super fun challenge!

  4. This is such a great way to encourage problem solving skills and imagination in young inventors. It was lovely to be apart of it.

  5. Bek @Just For Daisy says:

    Wow! So clever! Love love love this! 🙂

  6. It’s amazing how much fun (and problem solving) can be had with some simple materials and a little direction – I loved seeing all the different results! Opportunities like this really get the creative juices flowing.

  7. Loved reading this and seeing what the kids came up with. So awesome.

  8. Thank you for these wonderful ideas!! Would love to have more ideas for these mystery bags!

    1. I am so glad you like them, Simona. Let me see what other ideas I can come up with 🙂

  9. I LOVE everything about this idea & my engineer husband will, too! Thank you so much for sharing this gem!

  10. Tracy McKenzie says:

    I just got home from an oshc meeting and one of the topics was, can anyone think of an activity to fill a day for vacation care that is titled ‘Mystery day’
    Well I think I’ve found just the activity. Thank you for this fantastic idea, it ticks all the boxes for our children. just hope my boss thinks so as well. Thank you, thank you, thank you.

  11. My kids at school here in Holland LOVED this!! Thank you

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  13. What an absolutely BRILLIANT idea…..thank you so much!!!!!!!!!!!!!!!!!!!! My son will LOVE this!!!!!!!!!! Thank you!!!!!!!! (Can’t add enough exclamation marks!!!!)

  14. Thank you so much for these ideas! I am the science fair coordinator for my children’s middle school here in Pennsylvania and am trying to break away from the traditional science fair that most overwhelmed parents hate, but end up doing most of the work and running around. I am trying to come up with something just like this, but am looking for any more geared towards slightly older children. Any ideas?

    1. Hi Tracy! What a great idea! I’d love to hear how your science fair went. What a great idea, using these challenges as a non-traditional science fair I think this is the perfect solution to our participation problem. When you get a free minute, I’d love to hear the details about what you did, how it went, and what could have been improved upon! My wheels are spinning…I can hardly wait for the science fair this year!

  15. Matt Allen says:

    We are preparing for a STEM week at our school and I love this idea!! Do you have any more mystery bag challenges?

    1. I have some planned for this year, Matt, but they aren’t up yet. Good luck with STEM week, it sounds great.

  16. I think these activities could be used at any age. I plan to modify and use as an ice breaker for my high school art classes.

  17. Thank you for the ideas. I’m going to incorporate a makerspace component to my summer library so this is great!

  18. Randy Rodgers says:

    I REALLY like this idea. I am doing a session on maker spaces at a conference tomorrow, and it is going to include this, with credit given. I will also be using it in what I think will be an amazing part of our first district STEAM fair in February. I plan to have parents and students working together to take on whatever surprise task they choose. Thanks for sharing!

  19. Thank you for the ideas! My son and I are starting a science club at school and doing the pom pom launchers for our first activity next week 🙂

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  21. I am the volunteer executive director of a one-on-one after school tutoring program. We present our students with a challenge of the month and let them go at it. These two activities have sparked much enthusiasm. I am wondering if you have any more of these mystery bag ideas?

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