Encourage your toddler's endless curiosity with these entertaining and educational science activities tailored for preschoolers. These simple experiments feature beloved preschool pastimes such as bubble play, water exploration, arts and crafts, and messy fun!

We've categorized each activity based on difficulty level and required materials, making it simple for you to choose the perfect activity for your little scientist.

Difficulty:

• Easy: Requires minimal setup and materials, readily available at home or school.
• Medium: Requires some preparation and materials, easily obtainable.
• Advanced: Requires more planning and specific materials, and may need adult supervision.

Materials:

• Basic: Common household items like bowls, spoons, water, food coloring, and paper towels.
• Medium: Items you might need to buy like baking soda, vinegar, balloons, and magnets.
• Advanced: Specialized or more expensive materials.
• Remember: Always supervise children during activities and adjust difficulty levels according to their age and abilities.

Let us start with the activities:

1. Physical Science:

Easy:

1. Sink or Float?

This activity involves filling a tub or basin with water and collecting various objects of different materials (e.g., plastic, metal, wood, foam). Participants predict whether each object will sink or float based on their understanding of density and buoyancy. Then, they drop each object into the water and observe whether it sinks or floats. This activity helps reinforce concepts of density and buoyancy.

2. Rainbow in a Glass:

Participants fill clear glasses or containers with water and then add drops of different food coloring into each glass. As the food coloring mixes with the water, it creates a beautiful rainbow effect. This activity demonstrates the principles of color mixing and diffusion.

3. Shaking Up Colors

In this experiment, a clear jar is filled with water and a layer of oil is added on top. A few drops of food coloring are then added to the jar. When the jar is shaken, the food coloring mixes with the water but not the oil, resulting in distinct layers forming in the jar. This activity illustrates the immiscibility of oil and water and the concept of density.

4. Color Mixing Party:

Children can explore color mixing by setting up bowls with water and primary colors (red, blue, and yellow). They can use droppers or spoons to mix the colors and discover how they combine to form secondary colors (orange, green, and purple).

5. Magnetic Fishing: 

Children can attach magnets to strings and tie them to sticks to create fishing rods. They can then "fish" for metal objects such as paperclips or coins in a bin or bowl filled with sand or water. This activity introduces the concept of magnetism and helps children understand the properties of magnetic materials.

6. Dancing Raisins:

Children can observe the phenomenon of buoyancy and carbonation by placing raisins in a glass of club soda. The carbon dioxide bubbles in the soda attach to the rough surface of the raisins, causing them to float to the surface. As the bubbles pop, the raisins sink back down, creating a "dancing" motion. This activity provides a playful way to discuss concepts of density, buoyancy, and gas solubility.

7. Dancing Flames:

Sprinkle a small amount of pepper over a lit candle and observe how the pepper moves due to convection currents created by the heat from the flame. This activity introduces the concept of convection and thermal currents.

8. Mirror Magic:

Use mirrors to create reflections and explore concepts like symmetry and light bending. Children can observe how light reflects off the mirrors and experiment with changing the angles to create different effects.

9. Paper Towel Chain Reaction:

Set up dominoes made of rolled-up paper towels and knock them down in a chain reaction. This activity demonstrates cause and effect as children observe how the force applied to one domino causes a chain reaction, knocking down the others in sequence.

Medium:

10. Fizzing Volcano:

Baking soda and vinegar are mixed together in a container, causing a chemical reaction that produces carbon dioxide gas. This gas builds up pressure inside the container and eventually erupts, resembling a volcanic eruption. This experiment demonstrates the reaction between an acid (vinegar) and a base (baking soda) and the production of a gas.

11. Bouncing Balls:

Participants create bouncy balls by mixing glue, borax, and food coloring together. The mixture is shaped into balls and allowed to harden. Once formed, the bouncy balls can be bounced on a hard surface, and participants can explore their elasticity and bouncing properties. This activity introduces concepts of polymer chemistry and elasticity.

12. Balloon Rockets:

Balloons are inflated and attached to a straw using tape or string. The straw is then threaded onto a string or wire stretched across the room. When the balloon is released, the air escaping from the balloon propels it forward along the string. This activity demonstrates the principles of thrust, motion, and Newton's third law of motion.

13. Rainbow Chromatography:

Children can explore the principles of chromatography by using coffee filters, water, and markers. They can draw a line with markers on a coffee filter and then dip the bottom edge of the filter into water. As the water travels up the filter, it separates the colors in the ink, creating a rainbow effect. This activity introduces concepts of solubility, absorption, and separation techniques.

14. Balloon Stomp Rocket:

Children can experience the concepts of force and motion by tying inflated balloons to their ankles and stomping on the ground to release air. The escaping air propels the balloons forward, creating a "rocket" effect. This activity provides hands-on exploration of Newton's third law of motion and encourages discussions about thrust, acceleration, and direction.

15. Oobleck Fun:

Children can mix cornstarch and water to create oobleck, a non-Newtonian fluid that exhibits properties of both a solid and a liquid. They can explore the unique characteristics of oobleck by squeezing it, shaping it, and observing its behavior. This activity introduces concepts of viscosity, shear thickening, and material properties.

Advanced:

16. Crystal Growing:

Participants can grow crystals from solutions of sugar, salt, or alum by dissolving the substance in hot water and allowing it to slowly cool and evaporate. As the solution cools, crystals form and grow over time. Participants can observe the shapes and structures of the crystals formed.

17. Static Electricity:

Rubbing a balloon against hair or a woolen cloth creates a static charge on the surface of the balloon. This charged balloon can then attract small pieces of paper or even other balloons. 

18. Simple Machines

Participants can build simple machines such as ramps, levers, and pulleys using basic materials like wood, cardboard, and string. They can explore how these machines make work easier by reducing the amount of force needed or changing the direction of force. 

2. Life Science:

Easy:

19. Seed Sprouting:

This activity involves planting seeds in cotton balls or jars and observing their growth over time. Children can learn about the basic needs of plants such as water, sunlight, and soil nutrients as they watch the seeds sprout and develop into seedlings.

20. Beanbag Babies:

Children can create beanbag "babies" using fabric and filling them with beans or other soft materials. They can then care for their beanbag babies, mimicking real baby care routines like feeding, changing diapers, and comforting.

21. Nature Scavenger Hunt:

Take children outdoors for a scavenger hunt to collect natural objects such as leaves, rocks, flowers, and sticks. Encourage them to classify the items based on color, size, texture, or other characteristics.

22. Make a Worm Bin:

Children can create a simple habitat for worms by filling a container with soil and adding food scraps. They can observe the worms' movement and their role in decomposing organic matter, learning about the importance of worms in soil health and nutrient recycling.

23. Plant Detectives:

Children can go on a nature walk and use magnifying glasses to examine different plants up close. They can observe and discuss the parts of plants such as roots, stems, leaves, and flowers, learning about their functions and adaptations.

24. Nature Soundscape:

Children can record various sounds found in nature, such as birds chirping, leaves rustling, and water flowing. They can then use these recordings to create a calming soundscape for relaxation or as a background for other activities. This activity fosters appreciation for the natural world and promotes mindfulness.

Medium:

25. Make a Terrarium:

Children can create their own miniature ecosystems in jars or containers using soil, small plants, and decorative elements like rocks or figurines. They can observe how the plants interact with the soil and air inside the sealed environment, learning about the water cycle and plant growth.

26. Butterfly Garden:

Planting milkweed and other butterfly-attracting plants in a garden or container provides children with the opportunity to observe the complete lifecycle of butterflies. They can witness the transformation from egg to caterpillar to chrysalis to adult butterfly, learning about metamorphosis and the importance of pollinators.

27. Life Cycle of a Fruit:

Children can plant seeds from fruits such as apples or oranges and observe their growth into small trees over time. This activity allows them to witness firsthand the life cycle of plants, from seed germination to seedling growth to maturity.

28. Build a Bird Feeder:

Children can construct a simple bird feeder using recycled materials such as plastic bottles or milk cartons. They can observe and identify different birds that visit the feeder, learning about their adaptations for feeding and their role in the local ecosystem.

29. Egg Drop Challenge:

Children can design and build parachutes from various materials to protect an egg from a simulated "fall." They can test their designs by dropping the eggs from different heights and observing how air resistance affects the descent. This activity promotes critical thinking and problem-solving skills while also introducing concepts of physics and engineering.

30. Sprout Investigations:

Children can explore how different factors such as light, water, and temperature affect the germination and growth of seeds. They can conduct experiments by varying these factors and observing the rate at which seeds sprout and develop into seedlings. This activity provides hands-on experience with plant biology and the scientific method.

31. Make a Terrarium:

Create a miniature ecosystem in a sealed jar using soil, plants, and small critters like insects or worms. Children can observe how the plants interact with the soil and air inside the jar, learning about interdependence and the relationships between living organisms and their environment.

32. Mold Investigation:

Grow mold on bread slices under different conditions (light, dark, wet, dry) and observe the results. Children can discuss the importance of cleanliness and proper food storage to prevent mold growth, while also learning about the role of fungi in decomposition.

Advanced:

33. Microscope Exploration:

Using a toy microscope, children can explore microscopic organisms found in pond water, leaves, soil, or other samples. They can observe and identify tiny creatures like protozoa, algae, or microorganisms, learning about their adaptations and roles in the ecosystem.

34. Composting:

Starting a small compost bin allows children to learn about the decomposition process and the importance of recycling organic waste. They can add food scraps, yard trimmings, and other organic materials to the bin and observe how they break down into nutrient-rich compost over time, supporting plant growth and soil health.

35. Investigate Animal Adaptations:

Children can research different animals and their unique adaptations to survive in their environments. They can study features such as camouflage, mimicry, migration, or specialized body parts like beaks or claws, and discuss how these adaptations help animals find food, avoid predators, or cope with changing conditions.

3. Earth Science:

Easy:

36. Make a Suncatcher:

Children can create suncatchers using colorful tissue paper and glue. As sunlight shines through the suncatchers, they can observe how light passes through different colors and discuss concepts of light and color.

37. Cloud Watching:

Children can observe different types of clouds in the sky and discuss how they form. This activity provides an opportunity to learn about weather patterns and atmospheric conditions that influence cloud formation.

38. Sandcastle Construction:

Building sandcastles at the beach or in a sandbox allows children to explore the properties of sand, water, and gravity. They can experiment with building techniques and observe how structures are affected by environmental factors like tides or rainfall.

39. Volcano in a Bottle:

Create a mini volcano eruption by combining baking soda, vinegar, and dish soap in a bottle. As the ingredients react, they produce gas bubbles that mimic the eruption of a volcano. This activity introduces children to volcanic processes and landforms.

40. Make a Mini-Globe:

Use an inflated balloon, continents cut from construction paper, and tape to create a simple model of Earth. Children can discuss Earth's geography and landmasses as they place the paper continents onto the balloon to represent the continents and oceans.

Medium:

41. Moon Phases:

Using cookies or playdough, children can create models of the moon to demonstrate its different phases. By manipulating the shapes of the cookies or playdough, they can understand how the relative positions of the sun, earth, and moon result in the varying appearances of the moon over time.

42. Erupting Ice Volcano:

Children can construct miniature volcanoes using baking soda, vinegar, and dish soap. As the ingredients react, the volcano "erupts," allowing children to discuss the processes involved in volcanic eruptions and the role of plate tectonics in shaping the Earth's surface.

43. Make a Rain Gauge:

Children can build a simple rain gauge to measure rainfall over time. By monitoring the amount of precipitation collected in the gauge, they can learn about the water cycle and how weather patterns influence rainfall.

Advanced:

44. Rock Investigation:

Children can collect samples of different types of rocks and classify them based on characteristics such as texture, color, and formation. This activity provides insight into the rock cycle and the processes that shape the Earth's crust over time.

45. Stargazing:

On a clear night, children can go outside and observe the stars, constellations, and planets visible in the night sky. This activity offers an opportunity to discuss celestial bodies, the structure of the universe, and the concept of space exploration.