Lesson Plan

Climate Change #3 - Carbon Sinks

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Grade Level:
Upper Elementary: Third Grade through Fifth Grade
Lesson Duration:
30 Minutes
Additional Standards:
ESS2.A, ESS2.C, ESS3.C, ESS3.D, LS1.C, LS2.A, LS2.B, PS1.A, PS1.B, PS3.D


Students will explain how photosynthesis leads to carbon being taken out of the atmosphere.


The greenhouse effect happens because CO2 is transparent to the solar radiation emitted by the sun. But, when this radiation is partially reflected by the Earth as infrared or thermal radiation that radiation is then absorbed and reemitted in all directions including back at the earth by the CO2.  This effect leads to the Earth being 59.4 degrees warmer than it would be without CO2 and other greenhouse gases. As more CO2 is added to the atmosphere, by human and natural means, the atmosphere will heat up.


Materials: CO2 signs (provided in templates), Ribbons/Chalk/Rope (blue, green), blanket


Download Templates


1. For this activity print several CO2 signs. For the next lesson, you will need several of the signs that are labeled Oil, Gas, and Coal. (Depends on class size)


2. Begin by referring to Carbon Cycle Capture Lesson Plan (Climate Change #1) and Photosynthesis/Respiration Lesson Plan (Climate Change #2). Then ask if all the plants are eaten (No). Therefore lots of carbon stays in the plant material. Talk about the amount of carbon that is stored in forests and plants.

3. Lay out the green (plants) and blue (atmosphere) circles close to each other. Add a few students holding CO2 signs to the atmosphere. Have them be absorbed by plants then add some more students to the atmosphere and repeat until plant circle is full. These plants act as a carbon “sink” removing CO2 from the atmosphere.


4. Ask the students what would happen if all the plants were removed. Move the students to the atmosphere.

5. Put a blanket over the students to represent the trapped heat energy. Remind the students that the formation of CO2 releases heat. Tell them that CO2 is a greenhouse gas in the air that acts like a blanket trapping warm air. Creating more CO2 in the air is like adding more blankets, making everyone hotter. As long as the plants are living or buried in the ground the carbon remains part of the structure of the plant and is not released into the atmosphere.


6. Have the students brainstorm things that could remove the plants and release the carbon. Examples might include animals eating, forest fires, urban development, and burning fossil fuels.

Assessment Materials

Discussion Questions

How are plants carbon sinks?
(The plant takes CO
2 out of the air and uses the carbon to make sugar, which is stored in the plant. As long as the plant is alive, the carbon will not return to the atmosphere.)

Have the students brainstorm things that could remove the plants and release the carbon.


(Answers will vary. Possibilities include the plant dying and decomposing. The plant could be eaten and the carbon released during the respiration process of the animal. A forest could be bulldozed to put in a parking lot. Fire could burn the plants releasing the carbon. Burning of fossil fuels)

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Last updated: September 21, 2016