Tiny seedlings grow and transform into trees with a great quantity of matter.
Develop a model to explain where all the matter in a tree comes from when it begins as a small seedling. Develop a model to describe the observable and unobservable variables that explain how trees rearrange matter to support growth.
Introduce anchoring phenomenon: Tiny seedlings grow and transform into trees with a great quantity of matter.
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In this lesson, students will observe a time-lapse video of a seed growing into a large tree to develop an initial model to explain how plants transform matter from the surrounding environment to create new plant material. Students will make observations from the video, ask questions, and develop an initial model. Student questions and models will be revised in later lessons as they gather additional evidence regarding the transfer of matter and energy within the system.
Throughout the lesson, a flag () denotes formative assessment opportunities where you may change instruction in response to students’ level of understanding and making sense of phenomena.
One 60-minute session
Develop a model to explain where all the matter in a tree comes from when it begins as a small seedling. Develop a model to describe the observable and unobservable variables that explain how trees rearrange matter to support growth.
Students who are learning English or who are below grade level may communicate their ideas more clearly using pictures or symbols. The intent here is not to make a model, but rather to give students another option for how to express their ideas. At this point, it is not necessary for students to communicate in complete sentences or with accurate grammar and spelling.
This can also be presented on a display so that students can record their thinking in their science notebook. See an example of this modification in 7.1.R1: Display Idea for Giant Sequoia Tree Probe.
The growing tree video shows a seedling growing into a large tree. This is an opportunity to assess students’ prior knowledge about the phenomenon and determine what knowledge they are bringing to the unit. Students should notice the addition of a significant amount of matter to the tree, the development of new branches, and green leaves. If the majority of your students bring up ideas such as photosynthesis or chemical reactions, this could be an indication that the students have advanced knowledge of the phenomenon. However, it may also be an indication that students have heard of these terms but do not have a deep understanding of the underlying concepts. Monitoring their conversations and science notebook entries will help to determine students’ level of understanding.
These experiences do not need to be scientific. Encourage students to share experiences related to growing plants that reflect their home and family experiences. It is also appropriate for students to share experiences that they cannot fully explain such as why a family member planted something in a particular area or repotted plants. The intent is to gather personal and community connections to the phenomenon.
Students learning English can be encouraged to use their drawings in their science notebook to communicate with their partners. As students share their ideas with the class, revoice student ideas so that students who are learning English or may have limited academic vocabulary can have the opportunity to hear their ideas again and in a variety of contexts. For example, you might say, “So you noticed that the tree grew taller faster than it grew wider.”
This is an opportunity to assess students’ prior knowledge about developing and using models to determine what knowledge they are bringing to the unit. Record if students are using observations from the video or the list of related phenomena in their models (evidence), if the models contain visible and invisible components, and if the models show relationships. If this is the first time students have made a model, they may need some encouragement to record their ideas. Remind students that this model will represent their initial thinking, and there will be opportunities to add or revise their models later. This is also an opportunity to assess students’ prior knowledge related to the CCC Energy and Matter. For example, are students including both energy and matter elements in the model? Is matter represented as particles in any part of the model? Are there indications that matter is changing form or transported through the system?
Keeley, P., Eberle, F., & Tugel, J. B. (2007). Uncovering Student Ideas in Science, 2:25 More Formative Assessment Probes. Arlington: National Science Teachers Association.
Muviag. (2011, March 2). The growing tree / Timelapse Animation. Retrieved from https://www.youtube.com/watch?v=RjnKAWxCK3k.