20 STEM Activities for Preschool Classrooms
20 hands-on STEM activities for preschoolers. Science, engineering & math projects using simple materials that build curiosity and critical thinking.
STEM in preschool isn't about equations and lab coats. It's about curiosity, exploration, and asking "What happens if...?"
Young children are natural scientists. They experiment constantly—dropping things to see if they fall, mixing substances together, testing how fast they can run. These 20 activities channel that natural curiosity into foundational STEM learning.
Why STEM Matters in Preschool
Early STEM experiences:
- Build critical thinking: Children learn to observe, hypothesize, and test
- Develop problem-solving skills: Engineering challenges require persistence
- Create positive attitudes toward learning: Wonder and excitement, not worksheets
- Prepare for school success: Early math especially predicts later academic achievement
- Promote equity: Early exposure reduces gaps that widen over time
Science Activities
1. Sink or Float Experiments
Fill a large tub with water. Gather objects of various materials and weights. Children predict whether each will sink or float, then test.
Materials: Water tub, various objects (cork, rock, plastic toy, metal spoon, leaf)
Discussion prompts:
- What do you notice about things that float?
- Does size matter? Test small and large items of the same material.
- Can you find something surprising?
Science concepts: Density, buoyancy, prediction, observation
2. Volcano Eruptions
The classic baking soda and vinegar volcano never gets old. Place baking soda in a container, add vinegar, and watch the fizz.
Materials: Baking soda, vinegar, container, tray for mess
Extensions:
- Add food coloring for effect
- Test different amounts of each ingredient
- Try adding dish soap for more bubbles
Science concepts: Chemical reactions, cause and effect
3. Magnet Exploration
Provide magnets and a collection of objects. Children discover what sticks and what doesn't, then categorize.
Materials: Various magnets, metal and non-metal objects, sorting trays
Discussion prompts:
- What do all the sticky things have in common?
- Can magnets work through paper? Fabric? Let's test.
Science concepts: Magnetism, properties of materials, categorization
4. Color Mixing Laboratory
Provide primary color water (water with food coloring) and clear containers. Children mix to discover secondary colors.
Materials: Red, yellow, blue colored water, clear cups, droppers
Extensions:
- Create color wheels
- Try to make brown (all colors)
- Document results on a chart
Science concepts: Color theory, measurement, documentation
5. Plant Growth Observation
Plant seeds in clear containers so roots are visible. Track growth over time with drawings or photos.
Materials: Clear cups, seeds, soil, water, observation journals
Discussion prompts:
- What do plants need to grow?
- What happens if we don't water them?
- Why do roots grow down?
Science concepts: Plant biology, observation over time, needs of living things
6. Shadow Investigations
On sunny days, trace shadows in the morning and afternoon. Compare how they change.
Materials: Chalk, outdoor space, objects to cast shadows
Extensions:
- Use flashlights indoors to create shadows
- Make shadow puppets
- Build structures to create interesting shadows
Science concepts: Light, Earth's rotation, observation
Technology Activities
Technology for preschoolers isn't just screens—it's using tools to solve problems.
7. Simple Machine Discovery
Set up stations with ramps, pulleys, and levers. Challenge children to move objects using these tools.
Materials: Ramps, string/pulleys, lever boards, objects to move
Challenges:
- How can you get the ball to the top of the shelf?
- Can you lift this heavy book without picking it up?
Science concepts: Simple machines, force, mechanical advantage
8. Balance Scale Explorations
Provide a balance scale and various objects. Children discover which items weigh more through direct comparison.
Materials: Balance scale, objects of various weights
Extensions:
- Can you find two things that balance exactly?
- How many blocks equal one apple?
Math concepts: Measurement, comparison, equivalence
9. Light Table Exploration
If you have a light table, add translucent materials for sorting, building, and creating. The light adds a magical quality.
Materials: Light table, translucent shapes, x-rays, leaves
Activities:
- Sort by color (light changes perception)
- Build with transparent blocks
- Examine natural objects
Science concepts: Light, color, observation
Engineering Activities
Engineering for preschoolers means building, testing, and improving.
10. Bridge Building Challenge
Provide materials and challenge children to build a bridge between two blocks that can hold a toy car.
Materials: Blocks, cardboard, paper, tape, toy car for testing
Process:
- Build a bridge
- Test with car
- If it fails, discuss why and improve
- Test again
Engineering concepts: Structural integrity, iteration, problem-solving
11. Tower Challenge
How tall can you build before it falls? Document the tallest tower each day. Discuss what makes towers stable.
Materials: Blocks, cups, boxes—any building materials
Discussion prompts:
- Why did it fall?
- What could make it stronger?
- Does a wider base help?
Engineering concepts: Stability, balance, center of gravity
12. Ramp Races
Build ramps at different angles. Race cars down and measure how far they travel. Change variables and test again.
Materials: Boards for ramps, blocks for support, toy cars, measuring tape
Variables to test:
- Ramp angle
- Surface texture
- Car type
Science/engineering concepts: Gravity, friction, variables, measurement
13. Cardboard Construction
Save cardboard boxes and tubes. Provide tape and challenge children to build—houses, vehicles, robots, whatever they imagine.
Materials: Cardboard, tape, scissors (adult use), markers for details
Skills: Spatial reasoning, planning, problem-solving
14. Pipe Building
Pool noodles, PVC pipes, or cardboard tubes make excellent building materials for large-scale engineering.
Materials: Tubes of various sizes, connectors if available
Challenges:
- Build something a ball can roll through
- Create a structure taller than you
- Connect to a friend's structure
Engineering concepts: Connection, planning, collaboration
Math Activities
15. Pattern Making
Create patterns with objects and invite children to extend them. Start simple (AB) and increase complexity (ABB, ABC).
Materials: Any small objects in sets—blocks, buttons, beads
Extensions:
- Create patterns with sounds (clap-stomp-clap-stomp)
- Find patterns in the environment
- Create movement patterns
Math concepts: Patterns, prediction, algebraic thinking
16. Sorting and Classifying
Provide collections of objects for sorting. Children create their own categories—the thinking matters more than the result.
Materials: Mixed collections (buttons, shells, lids, toys)
Discussion prompts:
- How did you decide to sort them?
- Can you sort the same things a different way?
- What's another way to group these?
Math concepts: Classification, attributes, flexible thinking
17. Measurement Exploration
Provide non-standard measuring tools (links, blocks, handprints) for measuring objects around the room.
Materials: Linking cubes, blocks, paper handprints, items to measure
Activities:
- Measure the table in blocks
- Measure friends in handprints
- Compare results
Math concepts: Measurement, comparison, non-standard units
18. Counting Collections
Gather collections of interesting objects (buttons, shells, keys). Children count and organize to keep track.
Materials: Interesting collections, sorting trays, number cards
Extensions:
- Estimate before counting
- Group by tens
- Compare collections
Math concepts: Counting, organization, cardinality
19. Shape Hunt
Go on a shape hunt around the classroom or outside. Find circles, squares, triangles, and rectangles in the environment.
Materials: Shape cards for reference, clipboard for recording
Extensions:
- Sort found shapes
- Build shapes with bodies or sticks
- Create shape collages
Math concepts: Geometry, spatial awareness, vocabulary
20. Graphing Activities
Create simple pictographs of classroom data—favorite colors, pets at home, types of shoes worn today.
Materials: Chart paper, sticky notes or pictures, markers
Discussion prompts:
- Which has more?
- How many more?
- What can we learn from our graph?
Math concepts: Data collection, comparison, representation
Creating a STEM-Rich Environment
Materials to Have on Hand
Keep these available for spontaneous STEM exploration:
| Category | Materials |
|---|---|
| Building | Blocks, Legos, cardboard, tape |
| Science | Magnifying glasses, magnets, containers |
| Math | Counters, dice, measuring tools |
| Tools | Child-safe scissors, tweezers, eyedroppers |
Documentation
Make learning visible:
- Photograph experiments in progress
- Create "Our Discoveries" bulletin boards
- Keep science journals with drawings and dictation
- Share with families through daily reports
Teacher Role
In STEM activities, teachers:
- Ask questions rather than give answers
- Model curiosity and genuine wonder
- Allow struggle before helping
- Celebrate failure as learning
- Document and extend children's ideas
Common Questions
How do we fit STEM into an already full schedule?
STEM integrates into existing activities. Water table becomes sink/float. Block area becomes engineering. You don't need separate "STEM time."
What if I'm not good at science?
You don't need to know answers—you need to be curious. "I wonder..." and "Let's find out" are your most valuable phrases.
How do we manage materials and mess?
Set up designated areas, use trays to contain experiments, and establish cleanup routines. Some mess is inevitable and worthwhile.
Want to document STEM learning for families? Bloomily makes it easy to share photos and descriptions of hands-on learning, showing parents the science behind the play. See how it works or start your free trial.
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