That's Not a Plant, It's a Weed! Discovering Functions of External Plant Parts; What Makes a Plant a Plant?
Lesson 4 of 14
Objective: SWBAT identify external structures of plants and describe their function.
Materials to Gather: Prior to starting this lesson you will need a plant that has been freshly pulled from outdoors. Make sure the root system is intact. I chose a Dandelion. You will also need a classroom set of goggles and gardening gloves or rubber gloves to protect their hands.
Opening the Lesson: I held a little informal debate to open our lesson to clear up some misconceptions my students have about weeds vs. a plant. In a prior reading and writing homework assignment, many students noted that what they were looking at were weeds and not plants.There was also evidence from that interaction that they do not associate anything with flowers, as a plant. They classified them as "weed" or "flower". I suspect some perceive plants as only house plants, or vegetable plants in the garden. They think that if it is just green, it's a plant. I am not certain they understand that a tree is a plant. This lesson is intended to immerse them in a discovery experience to deepen their conceptual understanding.
On the Smart Board, I showed a my photo of a dandelion I had taken on my iPad. I told students that I wanted to know what they knew about the image in the photo by a playing a little game. (I purposely did not say "plant.")
I told my students that if they thought this was a plant to go stand on the right side of the room. If they thought it was a weed they needed to stand on the left. If they thought it was both, stand in the middle. One of my students went to the plant side, some stood in the middle and most went to the weed side.
I gave each group a small whiteboard with a marker. They chose one person as the designated writer. I told them to discuss why they chose to stand where they did and list the reasons on the whiteboard. I set the timer for four minutes and told them they needed to write as many reasons they could and be ready to defend their reasoning when the timer went off.
When the four minutes were up, we took turns talking about our reasoning. The "Weed" group declared that dandelions are weeds because they saw it on a commercial, you kill it with weed spray, it dies in a short period of time, and it kills grass. See Weed Group The "Plant" student said that it was a plant because it was pretty and yellow. See Plant only. The group that believed it was both wrote that it has seeds, grows anywhere, kills other plants, had pollen, grows flowers, has spikey leaves and is wild. They said they knew it was a plant because it fit what they had read in our prior lesson. See Weed and Plant Group
I told them that later we would discuss this again and see if anyone had changed their mind after we completed our field experiment and learned new understanding about plants.
I began this portion of the lesson by telling my students that our debate helped clarify that we need to think about plants more scientifically. In order to do so, we need to understand how they are classified. I tapped on their prior knowledge by asking them what they already know about plants. I referred back to the "Plants" and "Both" group's white board writing and asked them to think about it as we would list what we know to be true about plants.
I developed a KWL Chart on the white board. It was written across the board in three columns.
K: What I already know. W: What do I want to know? L: What I have learned!
I continued by asking: What do you know about plants?
We developed our list under the K section: Weeds kill grass. Grass-good. Weeds-bad. All plants have roots. Seed and non seed, Living things, Rid the planet of carbon dioxide and make oxygen.
I told them that these external parts are adapted to their environment in specific ways and that we need to be thinking about how those external parts work.
Next, I asked: What would you like to know about plants? I filled in the next column as they answered me. We listed questions under the W section: Why to they have roots? How can you tell how old a flower is? How do trees and plants make oxygen? Is the myth about trees where you turn it upside down true that the root system is the same size as the branches?
I told my students that the learning would take place through discovery and we would fill the "L" section during a sharing time the next day. I told them that their assessment of their learning today would be an Educreations Video and would be homework, due tomorrow. But first, we would need to know how to classify plants correctly.
I listed the learning goal for the day on the whiteboard: After we examine external parts of small plants, we will explain how we think the plant uses them to survive in its environment.
I explained to my students that in order to achieve our learning goal, they needed some more concrete understanding about how scientists classify plants.
I used Discovery Techbook as my resource. Discovery Techbook engages students in a logical way, giving them great movie clip resources, photos and reading passages. It is not completely aligned with NGSS yet. However, it is my best resource for this lesson. Our district has purchased this resource. I used the video in the Engage Section: Where Plants Live. This video helps students understand how scientist have to use criteria to classify plants.
After the video, I asked them to answer the question: How do scientists classify plants?
We discussed root systems and I drew three different types on my white board. I drew a deep tap root, a complex fiborous system and a shallow fiborous system. We talked about how leaves are different and that needles on pine trees are modified leaves. We talked about flowers and how fruit develops from apple tree flowers. I explained that all of these external parts serve the plant so that it can survive and that we can tell through observation how these parts function to help the plant adapt. It is springtime now and everything is blooming.It is perfect timing for this lesson!
(An optional resource, in case your district does not have Discovery Techbook, is Bill Nye: Plants, the full episode. However, this episode is 23:04 minutes long, and I suggest that it could be used in place of the first section of my lesson. This fun video gives students a detailed background knowledge about plants. I will use this video for my class in the future.)
I closed this section of the lesson by telling my students that we would be going outdoors to do some field work, they would need to wear their gardening gloves or the rubber ones I had provided, and their goggles at all times. We would first go over expectations and collect our materials before heading out.
Getting ready for the field: I told students they would be working in pairs, use the same plants, but create their own observations. They could talk and ask questions to one another to support learning. I told them they could list any questions they have in their notes section of their iPad and keep it for reference as they work. I told them that I expected at least 3 samples, but they could do 4 if there was time.
I also told them that there would be a strict rule that they would wear their gloves and goggles when handing their plants and that no one would be allowed to touch a plant until I approved their choice. (This prevents them from picking things like poison oak, ivy or stinging nettles or any plants that should not be pulled from the landscaping.)
I passed out the Classification Chart & Assignment- Plant resource and also brought it up on the Smart Board to model an example of how the chart should be filled out. I used explicit instruction and filled out one section of the chart, as I used a sample plant I had pulled from the ground earlier in the day. I did this because I know my group of students need this explicit guidance.I measured the root system showing them how to find the nearest centimeter. I told them that if there were seed on their plant, they should measure the length. There was no flower nor seed, but my sample had a long narrow tap root system. I measured it and filled in the chart. When I was done with this section, I asked if there was any questions about filling out the chart.
I asked them to turn the paper over and look at the vocabulary instruction and assignment as I went over every detail. I wanted them to understand that only specific language to describe. Some of the sample words listed could be used to help them. To check their understanding, I asked: Which is a specific description?
This is a cool plant! or This plant has wide and jagged edged leaves.
They chose the correct one! I concluded by asking them if there were any questions about the chart, vocabulary or assignment.
I reminded them that they needed their goggles, gloves rulers, iPads, clipboards, pencils and Classification Chart.
I partnered each of them strategically by considering each of their needs and personalities. After I was sure that everyone was ready, we headed out to the school yard and nearby wooded area to gather plant specimens.
Students looked in the school gardens and all around the wooded areas finding their samples. Field Work is engaging! I roved around, making sure no one was getting into anything that would hurt them. They picked mostly garlic mustard, creeping Charlie, grasses, and some bindweed. They measured and snapped photos with their iPads. There was busy chatter, and everyone was engaged. I stopped them from time to time to make sure they were on task and that data charts were full of specific descriptive words. I was certain there would be interesting samples for their data and for their Educreations Video.
Closure and Homework
Closure: I had everyone sit in a circle outside on the grass to close this lesson. I wanted to know if they had had enough time to find, measure, and observe at least three samples. I asked them to check their iPads and make sure they had photos of each applicable section from their chart. I wanted them to check that they had measured their samples' roots and any other part that would be included in the data. I asked everyone to look at their partner's work and make sure their buddy had everything listed that was needed.
Getting to the Heart of the Standard: I asked: What kinds of external parts did you see that would help you understand why the plant could live where it did? How do these parts function? Two students raised hands right away. One student talked about how hard it was to pull out the plant. ( They had a clump of grass by a fence line.) They could see that the roots were strong and the leaves were sharp. They thought this would help hold the plant in the wind that whips across the field.
I asked if weeds have the same external parts as plants. I asked: Are weeds plants? Students were able to understand that a weed is a plant and that it is not a classification, but a term used to identify a plant that is not wanted in a specific growing area.
Homework: We went inside so that I could present my Educreations video so they could completely understand what I was expecting them to do at home with their photos and data chart. Extra Support: I can email the sample of my lesson, and a pdf version of the filled out sample data chart to my students. This helps students be able to have personal resources as they develop their own Educreations lesson at home.
After I presented the video, I went back, replayed it, and stopped it at each photo so they could see how I used my photos to explain my evidence that classified it as a plant and why I thought its parts helped it survive in its environment.
We closed by taking time to answer any questions. Everyone understood the criteria listed on the back page. I got a thumbs up from everyone. The opening of the next science lesson will be examining our "W" questions we generated, and filling in the "L" part of our KWL chart, as I want them to fully synthesize their learning through creating their video first.