Section 1: Carrying Out Investigation

A. Exploring What Animals Breathe Out (20 minutes)

• Move students into pre-determined groups for the investigations and distribute the hand mirror (1).
• Invite students to open their student science notebook to the Water, Air, and Waste Matter entry and find the "Carrying Out Investigation" section.
• Display the Lab for Exploring What Animals Breathe Out.
• Explain that each group will follow the procedures to complete an investigation and they will record their observations in their student science notebook. Encourage students to record their observations using words and pictures.
• Remind students that because humans are animals, they will use their own breath for the investigation.
• Invite students to begin the investigations.
• Circulate to monitor and support students as they work. Encourage them to represent their observations in a model in their science notebook.
• After 10 minutes, ask students to clean up their materials and return to their seats.
• Reflect on the investigation by asking (2):

"How did the air on the mirror change when you breathed on it?" (The air became wetter--full of water vapor.)

"What does this experiment show us about the difference between the air from our bodies and the air all around us?" (The air in our bodies is different from the air around us because if they were the same, the mirror wouldn't have changed.)

"What do you think happens to air when it's in the human body?" (Responses will vary. Students may say that oxygen changes into carbon dioxide inside the body.)

"What does this tell us about how air flows within an ecosystem?" (The air changes as it enters and exits animals' bodies. Students will likely say there's a difference in the air but will likely not be able to articulate the difference.)

• Provide time for students to record their ideas (as well as their classmates') in their student science notebook.
• Invite students to return to their seats.

Section 2: Obtaining Information

A. Understanding the Roles of Plants, Animals, and Decomposers in Moving Matter (30 minutes)

• Tell students that as they watch the video they should record information about how water (a liquid) is moved by plants in a forest ecosystem in the "Obtaining Information" section of the Water, Air, and Waste Matter entry in their student science notebooks.
• Play "The Forest and the Water Cycle."
• Ask students to turn and talk to an elbow partner:

"What is the gist of the video?" (Plants take in water from their roots and release it through their leaves.)

• Display a picture of a stomata. Tell students this is a very magnified picture of a stomata--a special structure on the leaf of a plant.
• Tell students you are going to play the video again, and this time, they should pay particular attention to the words transpire, stomata, and vapor, how they are used, and what they might mean.
• Play the video again, pausing it as new vocabulary is introduced. At each pause point, let students turn and talk about the word and possible definition with an elbow partner.
• Once students have completed their second viewing, invite them to turn and talk to an elbow partner (1) (2):

"What new information have you learned about how water moves through an ecosystem?" (Plants move liquid water from the soil up through themselves all the way to the top of their leaves and release it as water vapor.)

"When plants first take in water, what state of matter is it--liquid, solid, or gas?" (liquid)

"When plants release the water to the air, what state of matter is it--liquid, solid, or gas?" (gas--water vapor)

"How does the water in the air become a liquid again?" (It condenses and becomes precipitation--like rain.)

"After rain or snow has fallen to the ground, where does the liquid water go?" (Trees suck it up, and the cycle starts again.)

"How might you capture this in your student science notebook? What should you write down?" (Water is cycled through the ecosystem by plants. They absorb liquid water and release water vapor, a gas. Then the water vapor condenses and falls as precipitation.)

• Give students a few minutes to capture their learning in their student science notebook.
• Tell them that they are now going to watch a video about how plants interact with air in a forest ecosystem. As they watch, they should try to determine the gist of the video.
• Show "The Forest and The Air Cycle."
• Ask students to turn and talk to an elbow partner (3):

"What is the gist of the video?" (Plants take in carbon dioxide and release oxygen as a waste product after photosynthesis.)

• Tell students you are going to play the video again, and this time, they should pay particular attention to the words carbon dioxide, oxygen, waste product, stomates, and chloroplasts, how they are used, and what they might mean.
• Play the video again, pausing it as new vocabulary is introduced. At each pause point, let students turn and talk about the word and possible definition with an elbow partner.
• Once students have completed their second viewing, invite them to turn and talk to an elbow partner (4):

"What new information have we learned about how air is cycled through an ecosystem?" (Plants change air from carbon dioxide into oxygen, which is useful for animals.)

"How can we capture this in our notebook? What should we write down?"

• Give students a few moments to capture their learning in their student science notebook.
• Ask students to turn and talk with a partner about how animals interact with gases and liquids in an ecosystem. Prompt them to think about themselves, since they are animals, and how they interact with air and liquid.

"How does liquid enter and exit your body?" (Animals drink liquids and release liquid as urine and sweat.)

"How does air enter and exit your body?" (Animals breathe in air that is a mixture of gases, including oxygen, and breathe out air that is a mixture of gases, including carbon dioxide.)

"How might you capture this in your student science notebook? What should you write down?" (Animals also play a role in the cycle of water and air in an ecosystem.)

• Give students a few moments to capture their learning in their student science notebook.
• Tell them that they are now going to watch a video about how solids are cycled through an ecosystem.
• Using a total participation technique, invite responses from the group:

"What do you already know about the way animals interact with solid matter?" (Animals eat solid matter and poop solid matter.)

"What do you already know about the way plants interact with solid matter?" (Plants use sunlight, water, and air to create solid plant matter.)

• Tell students that they will now learn about how decomposers interact with solid matter. As they watch the video this first time, they should try to determine the gist of the video.
• Play "Decomposers."
• Ask students to turn and talk to an elbow partner:

"What is the gist of the video?" (Decomposers break down dead plants and return nutrients to the soil.)

• Tell students you are going to play the video again, and this time, they should pay particular attention to the words fungi, humus, and castings, how they are used, and what they might mean.
• Play the video again, pausing it as new vocabulary is introduced. At each pause point, let students turn and talk about the word and possible definition with an elbow partner (5).
• Once students have completed their second viewing, invite them to turn and talk to an elbow partner:

"What are some examples of decomposers?" (earthworms, fungi, bugs, micro-organisms)

"What do decomposers do with solid matter?" (They break it down and return the nutrients to the soil.)

"How is the solid matter used in the soil?" (Plants use it to grow.)

"What is the purpose of the nutrients that decomposers return to the soil? Do they provide matter for the plants to grow?" (They provide trace amounts of matter, but they provide nutrients that help a plant function and grow.)

"What new information have you learned about how solids are cycled through an ecosystem?" (Decomposers break down solid dead things so that they are small enough for plants to absorb them. Plants create more matter, which animals eat and poop out, or plants die and decomposers continue the cycle.)

"How can you add this learning to your student science notebook?"

• Give students a few minutes to capture their learning in their student science notebook.

Section 3: Evaluating Information

A. Scientists Meeting: Building Understanding (30 minutes)

• Ask students to bring their science notebooks and gather for a Scientists Meeting.
• Using a total participation technique, invite responses from the group:

"What are the norms of a Scientists Meeting?" (take turns talking, build on one another's ideas, disagree respectfully, ask questions to clarify information)

• Remind students that a Scientists Meeting is a conversation where they speak to one another as scientists and not just to the teacher (1).
• Share with students that the goal of today's meeting is to build their understanding about how the way that water, air, and waste matter flows through an ecosystem relates to a healthy ecosystem.
• Ask for volunteers from a few groups to explain how their group added to and revised their explanatory model.
• Listen for students to name the movement of matter in general and then draw students' attention to the "Matter and Energy" column of the Concepts Scientists Think About anchor chart.
• Add the example "Matter is transported into, out of, and within systems" to the Concepts Scientists Think About anchor chart. Emphasize that matter is constantly flowing and moving throughout the ecosystem.
• Direct students' attention to the posted Life Science Module guiding question:
• "How do we assess and improve the health of an ecosystem?"
• Explain that they will evaluate the information they have collected about the way matter flows in an ecosystem in order to come to an understanding about what makes a healthy ecosystem.
• To elicit student learning, consider asking:

"Which criteria of a healthy ecosystem did you learn more about in this lesson sequence?" (all three of the criteria)

"What things are constantly moving in a healthy ecosystem?" (matter--in gas, liquid, and solid form)

"What new information can we add to our criteria about how the big cycles work in a healthy ecosystem?" (Matter is constantly flowing in an ecosystem. Plants, animals, and decomposers constantly cycle water, air, and waste matter in an ecosystem so that each type of organism has the matter that it needs.)

"What new information have we learned about how the abiotic features, like water, air, and solid waste matter, and the biotic features, like plants and animals and decomposers, interact?" (The abiotic and biotic parts of an ecosystem interact to move the matter. For example, plants take in water and release water vapor, which can affect the temperature.)

"What would happen to the rest of the system if there was a break in the cycle and plants stopped taking up water from the soil?" (It would all change--the water would fall to the ground and stay there, and the temperature would change because the water vapor in the air wouldn't be there.)

"What evidence would you observe in a forest ecosystem that water is cycling?" (plants growing; water falling as precipitation; clouds and water vapor in the air)

"What would happen if there were no decomposers and the waste matter wasn't cycled through the ecosystem?" (It wouldn't be as healthy--plants wouldn't get the nutrients they need and waste matter would pile up--plants and animals can't eat waste matter and keep matter cycling.)

"What evidence would you observe in a forest ecosystem that solid matter is cycling?" (rotting logs; mushrooms; fungi; earthworms and other insects that decompose; healthy plants growing)

"What would happen if there were no animals to breathe in air and the air stopped cycling?" (The plants wouldn't get the carbon dioxide they need for photosynthesis.)

"What evidence would you observe in a forest ecosystem that air is cycling?" (Plants are photosynthesizing and animals are breathing.)

• As students share out, encourage them to build on one another's ideas and remind students to use the information in their student science notebooks as evidence as they participate in the Scientists Meeting:

"Can someone paraphrase what Student A said?"

"Who thinks something similar to Student A?"

"Who thinks something different from Student A?"

"Can you add to what Student A said?"

• If conflicting information arises, help students challenge one another's ideas respectfully:

"Why do you think you have different conclusions from those of Student A?"

"With what in Student A's argument do you disagree? On what points do you agree? What evidence do you have to support those ideas?"

• As students come to consensus, record their ideas on the Criteria for Healthy Ecosystems anchor chart. (Refer to the Criteria for Healthy Ecosystems anchor chart in the supporting materials for guidance.)
• Assure students they will continue to build their understanding of these points and will return to the criteria for healthy ecosystems in the next lesson sequence.
• Invite students to return to their seats.