Leprechaun Trap – Rube Goldberg Machine Style Trap

St. Patrick’s Day is March 17, which means it is time to set up our Leprechaun Traps! Will you be lucky enough to capture a leprechaun this year? Test your Leprechaun Trap making skills by building a Rube Goldberg Machine device that moves!

DIY Rube Goldberg Inspired Leprechaun Trap

Leprechaun Trap - Rube Goldberg Machine

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Legend says there’s an Irish fairy called the Leprechaun. He is small in size, wears pointed shoes, a hat, and a leather apron. He lives alone in the forest, guarding his pots of gold and can be a mischievous little rascal! No wonder so many people try to trap these little green rascals!

St. Patrick’s Day is held on March 17 and is a day to celebrate everything Irish! It is packed with parades, good luck charms, and all things green. Leprechauns are one reason people wear emerald clothing. Otherwise, they’ll risk getting pinched! Wearing green makes us invisible to leprechauns, according to folklore.

Other fun St. Patrick’s Day traditions include the shamrock (three-leafed or the lucky four-leafed clover), Irish music played with bagpipes, and eating corned beef and cabbage.

All of these folklore stories inspire some incredible STEM learning opportunities, such as building a Rube Goldberg-style Leprechaun trap. Of all the DIY Leprechaun Trap ideas, this project provides an incredible STEM learning experience.

What’s a Rube Goldberg Machine?

Tap into kid’s inner engineer by creating a Rube Goldberg machine! This fun STEM project takes simple tasks and amusingly complicates them. Also known as a chain reaction, a simple job is completed in 3 or more steps. For example, action A triggers action B, which then causes action C, and so on, until the final goal is accomplished.

Rube Goldberg was an American cartoonist and artist. He was known for his drawings of elaborate contraptions. He was an engineer by trade and used his knowledge of science and simple machines to draw chain reaction illustrations.

Our Leprechaun Trap Rube Goldberg Machine Style Video

And here is a video of our Leprechaun Trap in action! If you can’t see the video, please ensure your adblockers are turned off as these also block our video feed.

Rube Goldberg Machine Video To Inspire

Need some inspiration and see some Rube Goldberg Machines in action? Check out OK Go and their incredible videos.

Leprechaun Trap Supplies

The possibilities are endless when it comes to supplies for Rube Goldberg machines! Look around your classroom or home for useful and interesting items. Think outside the box while gathering materials that will help you trap that sneaky little Leprechaun.

Here are some ideas to help you get started:

A Leprechaun

This is optional, but if you want to include a little Leprechaun in your trap you can use a Lego Leprechaun or you can make one out of construction paper. You might also want to include some St. Patrick’s Day themed items such as gold coins, pots of gold, rainbows, green construction paper, etc.

Things that Roll

Marbles, golf balls, tennis balls, bouncy balls, toy cars. Another alternative is to use a wind up toy like we did with our little caterpillar.


Long pieces of material that balls can slide down are helpful. Tip: Cut paper towel tubes lengthwise to make two half-pipe ramps. Train tracks from playsets, Hot Wheels tracks, marble runs, gutters, and plastic tubing can work well. We made a rainbow ramp out of some construction paper.

Dominoes or Blocks

Anything rectangular and with one flat side will work, i.e., erasers, matchboxes, decks of cards, books, wooden blocks, Jenga blocks, etc. You can also build these out of Lego.


Cardboard, shoe box, cereal boxes, cans, water bottles, etc.

Craft Supplies

Construction paper (especially gold, black and green construction paper)
Popsicle sticks
Pipe cleaners

Construction Materials

Masking tape
Hot glue gun
Glue stick

Construction Toys

LEGO bricks, K’nex, Tinker toys, and more! Anything that can be joined together to form a structure is perfect!

Directions – Building a Rube Goldberg Machine Leprechaun Trap

Identify the end goal of your Rube Goldberg Machine, which in this case is to trap that tricky Leprechaun! How this looks in your machine might be different from mine. I went with the goal being to close the lid on a shoebox to trap my Leprechaun, you might decide to use a different method for your trap – pop a balloon, knock over a tower, shut a door, etc.

Choose Your Supplies

Possible materials include: cardboard, water bottles, toilet paper or paper towel tubes, cereal or cake-mix boxes, books, cans, dominoes, marbles, golf balls, string, cups, etc. The best part of this project is that you can use materials you have available in your tinker kit, home or classroom, plus recyclables. Use what you have, you don’t need to spend a lot of money on this.

Sketch it!

Begin by sketching out your machine before building it. This will help you choose suitable materials, identify gaps, and assemble a device that works. This is an important skill for students to develop.

Build it!

Once you have your plan and supplies ready, start building!

Test it!

For a Rube Goldberg Machine to work everything must be precisely placed and timed. This requires testing to get everything perfect.

Rebuild it!

After you test, rebuild, making any necessary changes until you perfect your Rube Goldberg Machine Leprechaun Trap and trap your Leprechaun!

Rube Goldberg Machine Leprechaun Trap

Tips for Success

Building chain reaction machines involve a lot of work and a lot of time with trial and error being the main learning mechanism to achieve success. They require patience and perseverance – perfect for flexing and growing your STEM muscles!

Build your chain reaction machine knowing that it will need adjustments.

Start small! Begin with one step. For example, roll a ball so that it knocks over a wooden building block that in turn knocks over a small tower of paper cups. You will likely have to redesign your chain reaction to consistently work as expected.

Once you’ve experienced success, add another step. Perhaps a ramp or Hot Wheels track could be used to launch the ball that knocks over a series of 3 wooden blocks that knock over the tower of paper cups, and so on.

Work backward by starting at the end with the final step. Decide on the final task (how you are going to trap your Leprechaun) and then work your way back to the beginning.

Decide what you want to try. Then figure out what you need to do to accomplish that.

If the goal is to knock over a tower, figure out how to set up the building. Next, figure out what kinds of things could bump into the tower to knock it over. Then, figure out how to move those things to the building.

Use the Engineering Design Process! New to this approach? Learn more from NASA about the Engineering Design Process. First, review your supplies and decide on your challenge. Next, brainstorm and sketch some solutions. Then, build and test each segment of your design as you go. Observe what’s not working, tweak, retest, repeat. Remind yourself that mistakes help us learn. Most importantly – have fun!!

STEAM Principles and Lesson

Building a Rube Goldberg Machine Leprechaun Trap involves using engineering practices. Skills such as attending to precision, patience, and perseverance play critical roles in the success of designs. Failure (First Attempts In Learning) is expected in all engineering design challenges. Each attempt provides an opportunity to learn something new. This new knowledge can then be applied to make your machine even better!

Rube Goldberg machines do an outstanding job of illustrating potential and kinetic energy concepts. These two forms of energy can even be converted into each other! For example, a sled at the top of a snow-covered hill has potential energy (aka stored energy). When the sled travels down the hill, the potential energy is converted into kinetic energy (aka energy of motion), and speed is picked up.

Simply put, a Rube Goldberg machine can be viewed as a “potential energy device,” waiting to be converted into the energy of motion. This energy triggers the next event to occur, i.e., the wind-up toy knocks over the first domino, which then knocks over the next domino, and so on until your final goal, trapping the Leprechaun, is reached.

Newton’s Laws of Motion

Chain reaction machines also demonstrate Newton’s Laws of Motion. The First Law states that an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. If an object moves, it will not stop or change direction unless something pushes it. For example, if a ball is still, it won’t start moving all by itself.

The Second Law states that objects will move farther and faster when they’re pushed harder.

Newton’s Third Law is about force. It says that for every force, there’s an equal force acting in the opposite direction. This means there are always two forces acting upon each other simultaneously in opposite directions. For example, when an object is pushed in one way, there’s always resistance of the same size in the opposite direction.

Printables and Workbooks

Want to learn more about Isaac Newton? Check out our Famous STEAMists Workbook in the STEAM Powered Family Shop which covers: Albert Einstein, Leonardo da Vinci, Marie Curie, Isaac Newton, Stephen Hawking, Vincent van Gogh and Ada Byron Lovelace.

Cartoon images of famous scientists Einstein, da Vinci, Curie, Byron, Hawking, Newton. Vincent van Gogh. Overlay text says Famous STEAMists Unit Study

Celebrate St. Patrick’s Day with our St. Patrick’s Day Fun with Words printable pack from the STEAM Powered Family Shop. A fun classroom resource to explore vocabulary and decoding skills.

St. Patrick's Day Literacy Printable

Plus we have some free printables you can unlock simply by being a member of the STEAM Powered Family Mailing List. Enter your email here to unlock the printables.

More St. Patrick’s Day Activities for Kids

St. Patrick's Day STEM/STEAM Activity that includes some math, engineering, science and arts. A great STEM and STEAM activity for young scientists
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