I reengaged the kids by asking, "What do plants need to grow and survive?" The kids were quick to share that seeds/plants need water, soil, air (CO2), and sunlight to grow. I then asked, "How could you prove your thinking?" This question led us to an experiment that allowed the kids to test their ideas.
As a class, we planted grass seed in four different cups, four different ways.
Cup A: soil, sunlight, no water
Cup B: water, sunlight, no soil
Cup C: soil, water, no sunlight
Cup D: soil, water, and sunlight
The kids were VERY surprised with our results! They discovered that although plants can initially survive without soil, water, or sunlight, over time they will not thrive (and will likely die) when missing a necessary "ingredient". We also discussed that there are ways to successfully grow plants without soil, called hydroponics.
The kids also observed that the grass grown without sunlight was yellow, while the grass grown with sunlight was green. They hypothesized that sunlight makes plants green. I used this as an opportunity to discuss the substance inside a plant called chlorophyll. We discussed that chlorophyll is what makes the leaves/plant green and that the sunlight allows us to see the color of the chlorophyll. Without the sun, we cannot see the green chlorophyll.
We also discussed that like people, plants need food. The kids learned that plants can make their own food whenever they need it! Very cool! This is done by using sunlight, water, and CO2 (collected from the air) to make food (glucose).
It has been heartwarming to see the kids engaged and excited as they arrive in the classroom each morning, eager to check the progress of their experiment.
In addition to our experiment, the kids each planted their own grass seed, which they brought home this afternoon.