Saint Patrick’s Day STEM Activities

March is one of my absolute favorite months for hands-on learning, especially when it comes to Saint Patrick’s Day STEM activities. By this time of year, my kindergarten students have mastered classroom procedures, know how to share materials, and are finally ready to apply all the problem-solving and critical-thinking skills we’ve been practicing since the fall. It’s the perfect time to lean into open-ended exploration.

If you’re looking to add meaningful Saint Patrick’s Day STEM challenges to your classroom without spending a fortune, I’ve gathered some of my favorite low-prep, developmentally appropriate ideas. These activities focus on building, experimenting, predicting, testing, and revising, all while keeping the magic of March alive.

Lucky Charms Catapults

One of our biggest hits every year is building Lucky Charms catapults! Students use simple materials like craft sticks, rubber bands, plastic spoons, and small marshmallows to design a working catapult. The challenge? Launch marshmallows into a small cauldron.

This activity is perfect for Saint Patrick’s Day STEM because it naturally incorporates:

Engineering design
Measurement (How far did it go?)
Trial and error
Fine motor skills

I found small plastic cauldrons at the Target Dollar Spot, but you can also find similar sets on Amazon or substitute with small cups or bowls you already have. The key is not the materials, it’s the challenge. Encourage students to adjust their designs and test multiple times. Ask guiding questions like:

What happens if we add another craft stick?
Does pulling the spoon back farther change the distance?
How can we make it more stable?

The conversations that come from this are incredible.

Sink the Pot: Sink or Float Investigation

A simple sink-or-float investigation turns into a festive Saint Patrick’s Day STEM activity when you frame it as “Sink the Pot of Gold.”

Fill a bin with water and gather various small classroom objects. Students predict whether each item will sink or float before testing it. Then, challenge them to figure out how to make a small “pot of gold” sink or float, depending on your goal. Similar to my other sink vs. float lesson.

This connects beautifully to:

Scientific observation
Prediction skills
Recording results
Comparing materials

You can extend the lesson by discussing why certain materials sink, and others float. Even at the kindergarten level, students begin noticing patterns and properties of materials.

Saint Patrick's Day STEM - sink or float

Shamrock Crystals

Growing shamrock crystals is a fantastic way to incorporate science into your Saint Patrick’s Day STEM plans. Using pipe cleaners shaped into shamrocks and a borax solution (with teacher supervision), students observe crystal formation over time.

This activity introduces:

States of matter
Chemical reactions
Observation journals
Patience in experimentation

Have students draw what their shamrock looks like before placing it in the solution, then again the next day. The visual transformation is always exciting!

Saint Patrick's Day STEM - shamrock crystals

Color Mixing Rainbow Challenge

Rainbows and Saint Patrick’s Day go hand-in-hand, making a color mixing challenge an easy STEM win. Provide red, yellow, and blue paint or colored water and challenge students to create all the colors of the rainbow.

To increase the STEM component:

Have students predict what colors will mix together.
Let them test different ratios.
Challenge them to match a specific shade.

This blends art and science seamlessly while reinforcing primary and secondary colors.

Shamrock Sprouts

Planting shamrock seeds or quick-sprouting seeds (like grass) allows students to observe growth over time. This Saint Patrick’s Day STEM activity encourages responsibility and scientific thinking.

Students can:

Predict how many days it will take to sprout.
Measure plant growth with cubes.
Track changes in a simple observation log.

You can connect this to lessons about what plants need to grow and even experiment by placing one plant in sunlight and another in shade.

Penny Bridge Challenge

The Penny Bridge challenge is a favorite engineering task. Provide students with limited materials (paper, index cards, tape) and challenge them to build a bridge that can hold the most pennies (or “gold coins”).

To keep it developmentally appropriate:

Model how to test carefully.
Emphasize revising designs.
Celebrate effort, not just success.

This Saint Patrick’s Day STEM activity builds resilience. Students quickly learn that first attempts don’t always work, and that’s okay!

Simple Leprechaun Traps

I absolutely love leprechaun traps, but I’ll be honest, some examples online require a ridiculous amount of supplies. In my classroom, we keep it simple.

We use:

Printed leprechauns
Plastic gold coins
Building materials already in the classroom

That’s it.

When you give students open-ended materials and a clear challenge, “Build a trap to catch a leprechaun,” their creativity explodes. Some build towers, others design slides, and some create elaborate mazes. The magic is in the freedom.

You will truly be amazed at what children create when you allow for unstructured STEM exploration on Saint Patrick’s Day.

Why Saint Patrick’s Day STEM Works So Well in Kindergarten

By March, students are ready for:

Collaborative challenges
Independent problem-solving
Applying prior knowledge

Saint Patrick’s Day STEM activities provide the perfect seasonal hook while reinforcing:

Engineering design process
Scientific observation
Measurement and comparison
Critical thinking

And the best part? You don’t need expensive materials. Simple, open-ended supplies are more than enough.

If you’re looking to go even deeper with STEM in your classroom, you might also enjoy exploring how to design a STEM lesson from scratch, organize a school-wide STEM Day, or incorporate high-quality science books into your instruction.

However you choose to celebrate, I hope your classroom is filled with creativity, curiosity, and lots of “aha!” moments this March.

May the luck of the Irish be with you as you plan your Saint Patrick’s Day STEM activities!

If you are looking for some other STEM/Science/Saint Patrick’s Day resources, check out the following posts and products!