St. Patrick’s Day Science Activities and STEM Experiments for Elementary Students (K-5)

Looking for St. Patrick’s Day science activities your K-5 students will actually get excited about? You’re in the right place. This post rounds up 19 St. Patrick’s Day science activities and STEM experiments designed for elementary classrooms, from kindergarten through 5th grade, so you can celebrate the holiday without losing a single instructional minute.

The activities are organized by science domain: Physical Science, Earth Science, Life Science, and STEAM. Each one is tied to real science concepts, so you’re not just doing a fun holiday activity. You’re hitting curriculum goals at the same time. Whether you need a quick experiment to kick off the day or a full hands-on project, there’s something here for every grade level and every schedule.

St. Patrick’s Day Science Activities

From the fascinating physical science experiments that dive into chemical reactions and the properties of matter to earth and life science activities that explore plant growth and the human body, this collection promises a rich educational experience.

Each activity is designed to spark curiosity and learning, making science both fun and accessible for students, and seamlessly integrates with our grade-specific Science Stations Bundles for a comprehensive learning journey.

Physical Science Activities for St. Patricks Day

Below are 10 ideas for St. Patrick’s Day science activities and experiments that focus on properties of matter, irreversible changes, density, and much more! These experiments will make a great addition to our Third Grade Science Stations Bundle.

1. Gold Pennies

Best for: Grades 3–5

Ready for your students to make their own gold?

This is a great activity to teach them about chemical reactions and the properties of different metals. It will require safety equipment and lots of supervision.

Science concept: Students learn about chemical reactions and the properties of metals. When zinc-coated pennies are heated, the zinc and copper combine to create a gold-colored alloy — a visible, memorable example of how heat triggers chemical change.

2. Rainbow Rockets

Best for: Grades 3–5

Two words: Rainbow. Rockets. Your students will love this St. Patrick’s Day activity that teaches them about pressure and states of matter.

It will also cover the chemical reactions between dry ice and water. This exploding experiment can get a bit messy!

Science concept: Students explore states of matter and gas pressure. Dry ice sublimates (skips the liquid state and goes straight from solid to gas), building pressure inside the canister until it launches — a dramatic, hands-on introduction to cause and effect in physical science.

3. Leprechaun Ice Cream

Best for: Grades K–3

An activity that combines science with a sweet treat? Yes, please!

Teach your students about the freezing point of liquids and the chemical reactions of ice and salt. Let your students get creative when the ice cream is finished to make this the best green ice cream ever!

Science concept: Students investigate freezing point depression. Salt lowers the freezing point of ice, which pulls heat away from the cream mixture and causes it to freeze faster — the same principle used on icy roads in winter.

4. Magic Leprechaun Rocks

Best for: Grades K–3

Everyone loves baking soda and vinegar experiments.

This activity gives it a twist with magic rocks that might contain treasures. Your students will love watching the rocks explode in a fizzy mess and discovering the surprises inside.

Science concept: Students observe a classic acid-base reaction. Baking soda (a base) and vinegar (an acid) react to produce carbon dioxide gas, causing the fizzing and bubbling that breaks apart the “rocks” — an accessible, visual introduction to chemical reactions.

5. Fizzy Hunt for Leprechaun Gold

Best for: Grades K–2

Because we love fizzy science fun so much, we have another activity for you. This one also combines messy science with a coin hunt.

Science concept: Students explore the same acid-base reaction as above, but in a sensory discovery format. The focus here is on observation skills — watching, predicting, and describing what happens — making it ideal for introducing the scientific method with the youngest learners.

6. Rainbow Jar

Best for: Grades 2–4

We can’t have St. Patrick’s Day without rainbows. This fun activity will teach your students about the densities of different liquids while creating a beautiful rainbow.

Science concept: Students investigate density. Liquids with different densities (like honey, dish soap, water, and oil) stack in layers rather than mixing, creating a visible rainbow effect. Students learn that denser liquids sink while less dense liquids float on top.

7. Homemade Spectroscope

Best for: Grades 3–5

What makes a rainbow? With this activity, teach your students about light refraction and prisms. Kids can make their own spectroscopes, and they can take them home for hours of rainbow magic.

Science concept: Students explore light refraction and the visible spectrum. White light is made up of all colors; when it passes through a prism or diffraction grating, the wavelengths bend at different angles and separate into the colors of the rainbow.

8. Neon Rainbow Slime:

Best for: Grades 2–5

Let’s face it: kids love slime. A science experiment post would be incomplete without at least one St. Patrick’s Day slime-related activity.

It’s squishy, messy, and an excellent way for students to learn about viscosity and how temperature affects materials like slime.

Science concept: Students investigate viscosity and non-Newtonian fluids. Slime behaves differently from regular liquids — it flows slowly under low force but resists sudden pressure. Students also observe how temperature affects the slime’s consistency.

9. Rainbow Fluffy Slime

Best for: Grades 2–5

We said any hands-on science experiment post would be incomplete without at least one mention of slime. Well, we have two!

This is another great slime activity your students will love, but with fluffy slime! It offers a whole new world of textures, viscosities, and the reactions of different chemicals.

Science concept: Students explore polymers and the physical properties of matter. Adding shaving cream changes the texture and structure of the slime, giving students a chance to compare and contrast two similar substances and describe differences in texture, elasticity, and viscosity.

10. Giant Crystal Rainbow

Best for: Grades 3–5

Growing crystal experiments are always a hit. This St. Patrick’s Day experiment will teach your students how to grow giant rainbow crystals. It’s a wonderful experiment on sedimentation and chemical reactions.

Science concept: Students observe crystal formation and supersaturation. When a solution holds more dissolved material than it normally can at a given temperature, the excess material crystallizes as it cools — a slow, visible process that teaches patience and observation alongside chemistry.

St. Patrick’s Day STEM and STEAM Activities

These three activities will help your students explore science, technology, engineering, art, and math while having holiday fun!

11. Leprechaun Trap

Best for: Grades K–5

Get your students’ creativity and engineering skills flowing with this fun science activity. Who wouldn’t want to capture a leprechaun? You can use any materials to build your trap. The only limit is your students’ imaginations!

Science concept: Students apply the engineering design process — define the problem, brainstorm solutions, build, test, and improve. There’s no single right answer, which makes this activity ideal for developing creative problem-solving and persistence alongside basic physics concepts like force, balance, and structural stability.

12. St. Patrick’s Day Catapults

Best for: Grades 2–5

Here’s another great activity to improve your students’ engineering skills. They’ll have fun creating the best catapults and testing them out on your chosen targets.

Science concept: Students explore force, motion, and energy transfer. A catapult stores potential energy when pulled back and converts it to kinetic energy upon release — launching the projectile. Students can test variables like launch angle and arm length to see how they affect distance.

13. Shamrock Circuit

Best for: Grades 3–5

Are your students curious about how electrical circuits work? This activity will teach them the basics of circuits while having some St. Patrick’s Day fun.

Science concept: Students learn the basics of electrical circuits — how electricity flows through a closed loop to power a light or buzzer. They discover the difference between a complete and an incomplete circuit and practice the engineering skill of following a design to build a functional product.

Life Science Activities

The following three activities are a great addition to your life science studies.

14. Shamrock Sprouts

Best for: Grades K–3

Learning about the plant life cycle and growth? This activity offers a perfect opportunity to teach your students about plant life from seed to sprout.

Science concept: Students observe the plant life cycle from seed to sprout. They learn what seeds need to germinate (water, warmth, and sometimes light) and track changes over time — building observation and data recording skills alongside life science content.

15. Breathing Leaves

Best for: Grades 3–5

Do you have curious students who wonder how plants and trees use leaves for food and life? This experiment gives your students a visual representation of how leaves “breathe.” You can make it extra festive by using shamrocks instead of regular leaves.

Extra bonus: Combine this simple experiment with books on the subject to bring the full experience to life for your students.

Science concept: Students investigate photosynthesis and gas exchange. Leaves release oxygen bubbles when submerged in sunlit water, giving students a visual representation of a process that normally happens invisibly. Using shamrock leaves keeps the St. Patrick’s Day connection while grounding the activity in real plant biology.

16. Color-Changing Flowers

Best for: Grades 1–4

Color-changing flowers make a great experiment for any holiday. On St. Patrick’s Day, you can choose between rainbow-colored flowers or green flowers. Both offer the opportunity to learn about the different parts of a flower and their purposes.

Science concept: Students explore capillary action and the function of plant stems. Water mixed with food coloring travels up the stem and into the petals, showing students how plants move water and nutrients from roots to leaves — the same process that keeps all plants alive.

17. Walking Water Rainbow

Best for: Grades 2–4

This food coloring activity is a great way to teach your students about how capillaries work. You can use it when discussing how the human body works, or even when discussing plant life.

Science concept: Students observe capillary action in action. Water moves through paper towels from one cup to another — “walking” uphill against gravity — just as water moves through the capillaries in the human body and the xylem in plants. Works as a connection to both the human body and plant life units.

Earth Science Activities

18. Rainbow Water Cycle Bag

Best for: Grades 1–4

Place a zip-lock bag against a sunny window and watch the water cycle happen in real time. Students draw a simple scene inside the bag — clouds at the top, a sun, and a “pot of gold” at the bottom — then add a small amount of water mixed with blue and green food coloring. As the sun warms the bag, the water evaporates, condenses along the top of the bag, and eventually “rains” back down. It’s one of the most visual and low-prep ways to teach the water cycle at any elementary grade level.

Science concept: Students observe all three stages of the water cycle — evaporation, condensation, and precipitation — in a single, self-contained system. The bag acts as a closed environment that mimics Earth’s atmosphere, showing students how water moves continuously between the ground and the sky. The St. Patrick’s Day twist (rainbow colors + pot of gold) makes an abstract Earth science concept feel concrete and memorable.

19. Rainbow Weather Vane

Best for: Grades 2–4

Students build their own weather vanes using a pencil, a straw, cardstock, and a pin — then decorate the arrow in rainbow colors for a St. Patrick’s Day theme. Once built, students take their weather vanes outside to determine wind direction and record their observations over several days. This activity pairs well with a weather-journaling component in which students track wind direction alongside temperature and cloud cover.

Science concept: Students learn that wind has direction as well as speed, and that meteorologists use tools like weather vanes to track and predict weather patterns. Building their own instrument introduces the engineering side of Earth science — that scientists design and use tools to collect data — while the multi-day observation component builds skills in data recording and pattern recognition.

Scientific Method & Experiment Recording Sheets

These St. Patrick’s Day science activities are also a great opportunity to work in a little bit about the Scientific Method and Science Experiments. Show students how scientists work through a process that involves asking a question and searching for an answer.

The Scientific Method Posters and Science Experiment Recording Sheets are a great addition to the 19 St. Patrick’s Day Science Experiments. Here are a few photos from the Scientific Method Resource.

More St. Patrick’s Day Resources?

Are you looking for MORE St. Patrick’s Day resources? St. Patrick’s Day Craftivity is a great way for students to focus on how lucky they are.

More Seasonal Science Ideas?

Here are a few blog posts all about simpler science experiments that are great for any season:

• Halloween Science Experiments
• Thanksgiving Science Experiments
• December Holiday Science Experiments
• Valentine’s Day Science Experiments
• Earth Day Science Activities
• Easter Science Activities