This year, we implemented a brand new water cycle curriculum for our 3rd grade farm students. This lesson plan spanned approximately 6 weeks so the students could meaningfully engage with the stages of the water cycle.
Week 1
The 1st week was all about introducing the water cycle to the students at a broad scale. At this stage, the students discussed what they already knew about the water cycle – most of the students already knew some of the phase changes: evaporation, condensation, precipitation. To solidify their foundation of the water cycle, each student drew a picture of what they know now of the water cycle.
On the 2nd half of the 1st week, when classes returned to us for the 2nd time, we started a discussion about PRECIPITATION. Many of our students brought great information and definitions of precipitation, so to ground this lesson in the scope of our farm, we studied a rain barrel! The rain barrel for this lesson was set up a few weeks beforehand, and it has steadily been catching our winter rain and melting snow from the roof of our solar barn. We had each student take a yard stick, dip it into the rain barrel until it touches the bottom, pull it back out and take note of the number where the water line stops. Once each student was done, we compared and shared our results and noted them on a whiteboard, to record for future reference.
This lesson is important for getting students acquainted with taking scientific measurements, learning water conservation practices, and planting the seed of the difference between rainfall measurements and rain barrel collection measurements.
Week 2
Week 2 is all about EVAPORATION. We set up an experiment with 2 bowls, filled with a small amount of water, placed under our growing station. This location is important because of the grow lights positioned overhead that produce heat for this experiment (these lights will act as our representative “sun”). One bowl is left uncovered, and the other bowl is covered with plastic wrap. After setting up the experiment, we had a discussion on our hypotheses. A few students stated some ideas of water droplets forming on the plastic wrap – their minds are already stirring about condensation!
On the 2nd half of week 2, classes returned to check on the results of our experiment and to reflect back on our previous hypotheses, while conducting another discussion on the process that is happening between the 2 different bowls.
Week 3
As the precipitation falls, some of the water may evaporate, but some of it may also go through TRANSPIRATION, our topic of week 3! This was a new one for many students – so we really honed in on closely studying this topic. To demonstrate the process of transpiration, we set up 2 different cups: 1 with red food coloring, 1 with blue food coloring, and even some with purple food coloring! Next, we put sticks of celery into each cup, to let them drink up until next class.
During this stage, we heard some spouts of curiosity of students understanding that plants drink water, but wondering what role the food coloring plays in this experiment. Some students were even connecting the dots to last week’s topic by hypothesizing that some of the dyed blue water would evaporate into the air!
The next time we saw the students, we checked on our celery to see what happened! The food coloring made is easier to see how water moves up a plant through the xylem, to fully hydrate the plant all the way to the leaves. We then discussed what happens when the food coloring reached the top of the celery plant, ultimately deciding that some of the water evaporates off the leaves, leaving the color behind!
Week 4
The topic of week 4 is CONDENSATION. A few weeks ago, Farmer Hannah and Farmer Julian built a fog catcher on the farm comprised of a fine mesh, twine, PVC pipe, and a collection bucket. We went over how as a cloud of fog moves across the farm in the early morning hours, it gets caught in the mesh. As more and more mist settles on the mesh, it turns into larger water droplets and slides down the mesh, where it lands in the PVC pipe. The PVC pipe is slanted downward, so the water flows down the pipe and into the collection bucket. To demonstrate this, we played a game, similar to tag, where the person / water vapor who is “it” runs around collecting other water vapors in order to grow into a larger water droplet!
This lesson is great at showing the seemingly invisible aspects of the water cycle, and adds to the water conservation discussion brought up from the precipitation lesson. We are teaching our students that you can obtain water from a variety of different sources!
Week 5
Week 5 has the students reflecting on their previous investigation into the soil cycle as we delve into SURFACE INFILTRATION. For this lesson, the students set up an experiment by putting 3 different types of soil into 3 different containers: 1 container has clay, 1 container has silt, 1 container has sand. After the containers are filled with their respective soil, we made our hypotheses on which would drain water the fastest / slowest. We then poured water on them to see how quickly the water drains from each type of soil.
As a follow up, we did a deep dive into the reasoning behind the difference of water flow with a classroom discussion. To get students thinking, I posed the question: “If you were a plant, which type of soil would you like to live in?”
For the second half of this week, we covered SURFACE RUNOFF – our last topic of the water cycle. This lesson builds slightly off of last week’s lesson as students will be investigating how water runs off different surfaces: grass, dirt, and concrete. We will begin our investigation with our hypotheses, then teams will be sent out to test our hypotheses. Each team will be responsible for locating a grassy downward slope, a dirt downward slope, and a concrete downward slope. Each team will have a small bowl of water (filled by our trusty rain barrel!) which they will pour down their slope, and then will measure how far the water traveled with a tape measure. Each group will write down their observations, and then share their findings with the class. During this share-out, we touched on the implications that surface runoff has on pollution and erosion.
Week 6
For our final week, we returned to our 1st rendition of our water cycle drawings to create a more complete diagram of the water cycle. Since all the students are more familiar with each phase, and how they interact with one another, they have a more holistic understanding of the entire cycle.
We closed our water cycle lesson plan with a circle discussion. Students could pick among the following questions:
- What was the most surprising part of the water cycle?
- What was you favorite part of the water cycle?
- What was the most challenging part of the water cycle?
I had such an amazing time with our 3rd graders during these lessons. The kids were engaged with all the experiments that we did and so excited to learn and ask questions. It was a great opportunity to work with the students to combine such a staple topic in the scope of our school garden.
South Whidbey School Farms 