Easy STEM Activities for Preschoolers: Science Made Fun

You don’t need a lab coat or a degree in chemistry to do STEM with preschoolers. At this age, science is about wonder, questions, and hands-on exploration. The best STEM activities feel like play—because that’s exactly how young children learn best.

These activities use simple household materials, require minimal prep, and tap into what preschoolers naturally love: making messes, asking “why,” and watching cool things happen. Each one builds foundational STEM skills while keeping little hands (and minds) engaged.

[Image placeholder: Preschooler watching color mixing experiment with wonder]

What Is STEM for Preschoolers?

STEM stands for Science, Technology, Engineering, and Mathematics. For preschoolers, this looks like:

Science: Observing, asking questions, making predictions, experimenting
Technology: Using tools, understanding cause and effect
Engineering: Building, creating, problem-solving
Mathematics: Counting, sorting, patterns, comparing sizes

At this age, formal instruction isn’t the goal. The goal is nurturing curiosity and showing kids that exploring how things work is fun.

Tips for STEM Success with Preschoolers

Ask questions, don’t give answers: “What do you think will happen?” “Why do you think that happened?” Questions build thinking skills.

Embrace mess and “failure”: Experiments that don’t “work” are still learning. Discuss what happened and try again.

Follow their lead: If they want to keep mixing colors instead of moving on, let them. Deep exploration beats checking off activities.

Use real vocabulary: Say “hypothesis,” “experiment,” and “observe.” Kids rise to the language we use.

Connect to their world: Relate activities to things they already know and care about.

Science Experiments (10 Activities)

1. Baking Soda Volcano

Materials: Baking soda, vinegar, food coloring, container
What to do: Build a “volcano” from playdough around a container. Add baking soda and a few drops of food coloring. Pour in vinegar and watch the eruption!
The science: Acid-base reaction creates carbon dioxide gas
Mess level: Medium

2. Color Mixing Magic

Materials: Clear cups, water, food coloring, paper towels
What to do: Fill cups with colored water. Connect cups with paper towels. Watch colors “walk” and mix as water travels up the paper towels.
The science: Capillary action, color mixing
Mess level: Low

3. Sink or Float

Materials: Basin of water, various household items
What to do: Gather items and predict: will it sink or float? Test each one and sort into piles.
The science: Density and buoyancy
Mess level: Medium (water)

4. Magic Milk

Materials: Milk, food coloring, dish soap, cotton swab
What to do: Pour milk in a shallow dish. Add drops of food coloring. Touch the center with a soapy cotton swab and watch colors explode!
The science: Surface tension disruption
Mess level: Low-medium

5. Growing Crystals

Materials: Borax, water, pipe cleaners, jar
What to do: Bend pipe cleaner into a shape. Dissolve borax in hot water. Suspend pipe cleaner in solution overnight.
The science: Supersaturation and crystallization
Mess level: Low

[Image placeholder: Child doing sink or float experiment with various objects]

6. Invisible Ink

Materials: Lemon juice, white paper, cotton swab, heat source (lamp or iron)
What to do: Write or draw with lemon juice. Let dry. Hold near heat to reveal the message!
The science: Oxidation from heat
Mess level: Low

7. Dancing Raisins

Materials: Clear soda (Sprite or club soda), raisins, clear glass
What to do: Drop raisins into the soda. Watch them sink, rise, and “dance.”
The science: Carbon dioxide bubbles and density
Mess level: Low

8. Static Electricity Fun

Materials: Balloon, small paper pieces or cereal
What to do: Rub balloon on hair. Use static to pick up paper pieces or move cereal across a table.
The science: Electrical charges
Mess level: None

9. Plant Growth Observation

Materials: Seeds, clear container, wet paper towel
What to do: Place seeds between wet paper towel and container side. Watch roots and sprouts grow over days.
The science: Germination and plant biology
Mess level: None

10. Rain Cloud in a Jar

Materials: Jar, water, shaving cream, food coloring
What to do: Fill jar with water. Top with shaving cream “cloud.” Drip food coloring on top. Watch it “rain” through.
The science: Water saturation, weather demonstration
Mess level: Low

Engineering Challenges (8 Activities)

11. Bridge Building

Materials: Blocks, books, or cardboard; small toys for testing
Challenge: Build a bridge that spans a gap and holds weight
Skills: Structural engineering, problem-solving
Mess level: None

12. Tallest Tower

Materials: Blocks, LEGO, cardboard boxes, or cups
Challenge: Build the tallest tower that stands on its own
Skills: Balance, stability, spatial reasoning
Mess level: None

13. Marble Run

Materials: Paper towel tubes, tape, cardboard, marble
Challenge: Create a track for a marble to travel from high to low
Skills: Gravity, angles, sequential thinking
Mess level: Low

14. Egg Drop Challenge

Materials: Egg, various cushioning materials (cotton, bubble wrap, fabric)
Challenge: Protect an egg from breaking when dropped
Skills: Material properties, impact absorption
Mess level: Potentially high (but worth it)

15. Boat Building

Materials: Foil, straws, tape, small tub of water, pennies
Challenge: Build a boat that floats and holds the most pennies
Skills: Buoyancy, weight distribution
Mess level: Medium (water)

[Image placeholder: Child building marble run from cardboard tubes]

16. Cardboard Box House

Materials: Large cardboard box, markers, scissors (adult help)
Challenge: Design and decorate a house with doors and windows
Skills: Spatial planning, design
Mess level: Low

17. Ramp Races

Materials: Flat surface (cardboard, board), blocks to prop, cars
Challenge: What angle makes cars go fastest? What surface?
Skills: Variables, slopes, friction
Mess level: None

18. Paper Airplane Testing

Materials: Paper, open space
Challenge: Which fold design flies farthest? Straightest?
Skills: Aerodynamics, testing variables
Mess level: None

Math Activities (6 Activities)

19. Pattern Making

Materials: Colored blocks, beads, LEGO, or snacks
What to do: Create patterns (ABAB, AABB, ABC) and have kids continue them
Skills: Pattern recognition, sequencing
Mess level: None

20. Sorting Collections

Materials: Buttons, shells, leaves, toys—anything with variety
What to do: Sort by color, size, shape, or any attribute. Count groups.
Skills: Classification, counting, comparing
Mess level: None

21. Measuring Everything

Materials: Rulers, measuring tape, blocks (as non-standard units)
What to do: Measure furniture, toys, family members. Compare: longer, shorter
Skills: Measurement, comparison, number sense
Mess level: None

22. Shape Hunt

Materials: Paper shapes or shape cutouts
What to do: Find shapes around the house. Circle? Rectangle? Triangle? Count how many of each.
Skills: Shape recognition, observation
Mess level: None

23. Counting Games

Materials: Small objects, cups, dice
What to do: Roll dice, count out that many objects. Compare amounts. Add groups together.
Skills: One-to-one correspondence, addition basics
Mess level: None

24. Graphing Favorites

Materials: Paper, stickers or stamps
What to do: Survey family about favorites (color, food, animal). Create a picture graph.
Skills: Data collection, visual representation
Mess level: None

Nature-Based STEM (6 Activities)

25. Bug Hunt and Observation

Materials: Magnifying glass, bug jar, notebook
What to do: Find bugs outside. Observe closely. Draw what you see. Count legs, look at colors.
Skills: Observation, documentation, entomology basics
Mess level: None

26. Weather Watching

Materials: Simple weather chart, thermometer
What to do: Check weather daily. Record observations. Notice patterns over time.
Skills: Observation, data tracking, meteorology
Mess level: None

27. Shadow Play

Materials: Sunny day, chalk, various objects
What to do: Trace shadows at different times. Notice how they change. Make shadow puppets.
Skills: Light and shadow concepts, earth rotation
Mess level: None

28. Nature Collections

Materials: Container, natural items found outside
What to do: Collect leaves, rocks, sticks. Sort and categorize. Create nature art.
Skills: Classification, observation
Mess level: Low

29. Bird Watching

Materials: Bird guide or app, binoculars (optional)
What to do: Watch birds in your yard or park. Identify species. Count visitors.
Skills: Observation, identification, counting
Mess level: None

30. Water Cycle in a Bag

Materials: Ziplock bag, water, blue food coloring, tape
What to do: Add water and coloring to bag. Seal and tape to sunny window. Watch evaporation and condensation.
Skills: Water cycle, observation over time
Mess level: None

[Image placeholder: Child examining bug with magnifying glass]

Creating a STEM-Friendly Environment

Ask lots of questions:

What do you think will happen?
Why did that happen?
What would happen if we tried…?
What do you notice?

Stock simple supplies:

Magnifying glasses
Measuring cups and spoons
Funnels and containers
Building materials (blocks, cardboard, tape)
Basic science supplies (baking soda, vinegar, food coloring)

Make exploration normal:

Wonder aloud about things together
Say “I don’t know—let’s find out!”
Celebrate questions as much as answers

FAQ

Is my preschooler too young for STEM?

Absolutely not! Preschoolers are natural scientists. They’re constantly experimenting, even if it looks like “making a mess.” These activities channel that curiosity productively.

What if experiments don’t work as expected?

That’s actually valuable! Talk about what happened and why. Real scientists’ experiments often don’t go as planned. The learning is in the process.

How do I explain the science without getting too complicated?

Keep explanations simple and concrete. “The bubbles are pushing the raisins up!” is perfect for preschoolers. Save detailed explanations for when they ask more questions.

Do I need to buy special materials?

Most activities use common household items. A few specialty items (magnifying glass, magnets) are worth having but aren’t required to start.

Conclusion

STEM for preschoolers is about fostering curiosity, not creating the next Einstein. The wonder in your child’s eyes when the volcano erupts or the colors “walk” across paper towels—that’s the foundation of scientific thinking.

Start with one activity this week. Ask questions, make predictions together, and see where their curiosity leads. You’re raising a little scientist, one experiment at a time.