7 Nature Experiments to Spark Student Curiosity

Children are natural scientists—they ask big questions, notice tiny details, and learn best through hands-on exploration. That’s why nature experiments are a classroom staple for me. From growing seeds to using the sun’s energy, students don’t just learn science, they experience it. Here are my favorite go-to nature experiments that spark curiosity.

1. Growing a Bean in a Cup

One of my favorite science experiments to bring to my fourth-grade classroom is growing beans in a cup. I typically use this activity to reinforce our botany lessons on plant parts and the life cycle of a plant, giving students a concrete, visual way to connect what they’ve learned in class to real plant growth. To try this experiment yourself, you’ll need clear plastic cups, damp paper towels, and bean seeds.

Students put the paper towels into their cups, followed by the seeds, and then the magic happens. Within days, roots and shoots appear. I encourage students to check on their seeds, using measuring tapes to track growth and sketching anything new they notice. While most students’ seeds will grow quickly, it is a good idea to have backup cups just in case, so that no students feel left out. You could also group students to track their growth as a team, noticing which seeds are growing faster and making predictions about why.

2. Water Cycle in a Bag

When I taught fifth grade, one of the most eye-opening experiments we did during our weather unit was the water cycle in a bag. I used it to bring vocabulary like evaporation and condensation to life. This activity lets students see these processes happening right before their eyes. To set it up, you’ll need zip-top plastic bags, water, permanent markers, and a few drops of blue food coloring for a clear visual effect.

Students start by drawing the sun, clouds, and a body of water on their bags with markers. Then they add water, seal the bags, and tape them to a sunny window. Over time, they watch water evaporate, condense, and “rain” inside the bag. I ask students to make daily observations using key vocabulary. For extra support, I model sentences or provide starters. If a bag shows slow changes, I suggest moving it to a brighter spot.

3. Water Filtration in a Bottle

I like using this experiment with my sixth graders during our ecosystems unit to help them understand how wetlands naturally clean and filter water. It’s a hands-on way for students to build, test, observe, and reflect while exploring an important environmental concept. To try this, you’ll need empty plastic bottles, scissors, gravel, sand, soil, moss, grass, and some “dirty” water made by mixing leaves, twigs, and soil into water.

Students start by cutting the tops off their bottles and inverting them to create funnels. For quicker setups, precut bottles can be handed out. They then build their filters by layering the natural materials inside. Once ready, they pour in the murky water and watch it filter through. I ask them to record observations and reflect on which materials worked best. Some students adjust their filters to improve results, while others compare methods.

4. Compost in a Bottle

With my fourth graders, I use the compost-in-a-bottle experiment to help students understand decomposition by watching it happen. This activity supports our lessons on the nutrient cycle and shows how nature breaks down organic matter. For this experiment, you’ll need a clear container, kitchen scraps like apple cores and carrot and banana peels, eggshells, shredded newspaper, garden soil, and a spray bottle to keep everything moist.

Students start by layering their kitchen waste, shredded newspaper, and soil inside the bottle. Then, they lightly mist it with water and seal the bottle loosely to let air in. Over time, they watch the materials break down, often noticing the changes in smell and texture. Students compare different bottles with various ingredients to see which compost faster. One year, a student’s idea to add worms sparked a whole new level of excitement—it’s a bit messy but deeply engaging and a great way to explore natural cycles.

5. Photosynthesis in a Cup

I find that this experiment really helps my fourth graders grasp photosynthesis by making it visible, and it always sparks great questions and conversations. To set it up, you’ll need clear cups filled with water, a few leafy greens, and something like a pebble or small rock to keep the leaves underwater.

After filling their cups with water, students submerge a leaf and weigh it down with a rock. We place the cups on a sunny windowsill and watch closely. As tiny oxygen bubbles begin to form, I challenge students to become leaf detectives. I encourage them to document every detail and experiment with leaves of various shapes and colors to see how each reacts.

6. Build a Solar Oven

During our energy unit, I guide my sixth graders through this creative experiment where they build solar ovens that actually cook s’mores using sunlight. You’ll need recycled pizza boxes, black construction paper, aluminum foil, plastic wrap, tape, scissors, and pencils or sticks, plus marshmallows, chocolate bars, and graham crackers.

Students cut a flap in the pizza box lid and line the bottom with black paper to absorb heat. They tape foil to the underside of the flap to reflect sunlight and seal the opening with two layers of plastic wrap to trap warm air. After assembling, we find a sunny spot outside. Students adjust their flaps to capture sunlight and watch their s’mores slowly cook. I ask them to bake several mini s’mores using different flap angles and time each one to figure out which setup melts the fastest.

7. Leaf Chromatography

I use this experiment with my fourth and fifth graders during our lessons on photosynthesis and seasonal changes. This activity helps connect concepts like chlorophyll, photosynthesis, and how plants adapt in different seasons. You’ll need leaves in various colors, small jars, rubbing alcohol, coffee filter strips, and a container for warm water.

Students start by tearing leaves into small pieces and mashing them in jars, then covering them with rubbing alcohol. The jars are placed in a warm water bath to help release the pigments. Next, students dip strips of coffee filter paper into the jars and watch as the pigments separate into yellows, oranges, reds, and greens. I encourage them to observe carefully, compare different leaves, and keep their strips as fun reminders of what they learned.

These nature experiments bring science to life by connecting students directly with the world around them. They don’t just memorize terms—they see roots sprout, watch oxygen bubbles rise, and feel the sun’s power at work. That’s the kind of learning that sticks.