Teacher & Student Materials > Powering a Warming Planet

1.2 Where does anthropogenic (human-made) CO2 come from?

Lesson Overview

Guiding question:

Where does anthropogenic (human-made) CO2 come from? 

  • Time Estimate:

1 hour

Purpose:

This lesson introduces the relationships among climate change (specifically the rise of global temperature), the greenhouse effect, CO2 emissions, and the use of energy. Students will understand that the rise of global temperature is caused by the large amount of CO2 emitted by humans when using energy. Moreover, they will learn that the greenhouse effect is a natural phenomenon that helps maintain a suitable temperature range on Earth’s surface for living things. However, excessive greenhouse gases can cause Earth’s atmosphere to absorb more and more heat, leading to global warming.

Overview:

The lesson starts with students reviewing the correlation between global temperature change and atmospheric CO2 from 1950 to 2022. A demonstration is designed to illustrate how CO2 can absorb heat in the air and cause a rise in temperature. After watching a video introducing the greenhouse effect, students will learn that the greenhouse effect is a natural phenomenon. However, when too many greenhouse gases are produced by human activities, they disrupt the balance and lead to climate change. Lastly, a series of pictures will be presented to students, allowing them to connect CO2 emissions with energy use.

Design Principles:

  • Modeling
  • Argumentation
  • Science investigation

Background Knowledge:

The rise of global temperature is positively correlated with the atmospheric CO2. 

Common Misconceptions:

Students may think that greenhouse effect is caused by human activities. In fact, greenhouse effect is a natural phenomenon which is crucial to keeping our planet at a suitable temperature for life. Since the start of the Industrial Revolution in the mid-18th century, the extensive use of fossil fuels have greatly increased the concentrations of greenhouse gases in the atmosphere.

Safety:

Demonstration: How does CO2 impact the atmosphere temperature?

  • Teachers must remember to stop heating the jars immediately after measuring the temperature to prevent overheating, as this could lead to potential explosions due to excessive pressure buildup in the glass jars.

Demonstration – What emits CO2?

  • Teachers must prioritize safety measures when lighting up a candle during a classroom experiment.

Unit Connections:

This lesson use CER model for argumentation, which should be learned in the “Quenching the Thirsty Planet” unit. 

  • Materials

Teacher

Teacher Slides 1.2 Where does anthropogenic (human-made) CO2 come from?

Materials for demonstration:

How does CO2 impact the atmosphere temperature?

  • Containers: 2 jars with lid (identical, clear, transparent)
  • Water
  • Alka-Seltzer – 1 tablet
  • Measuring cup
  • Heat Source: there are a variety of options, heat lamp, space heater, a sunny window if you live somewhere with lots of hot direct sunlight, etc (It needs to provide lots of heat evenly between the jars)
  • Thermometers– 2; fit into the jar. 
  • Label and Sharpie (label the jars)

Demonstration – What emits CO2

  • A candle
  • CO2 detector
  • Match or fire lighter

Optional

Greenhouse effect lab worksheet

Instructional Sequence

Materials: Teacher Slides 1.2 Where does anthropogenic (human-made) CO2 come from?

Review the correlation between temperature rise and CO2 (Slide 2)

Remind students that we do not know the causality between the two factors from the two graphs. But today, we will explore the causality between them.

The Greenhouse effect demonstration (Slide 3)

Optional materials: Greenhouse effect lab worksheet

The goal of this demonstration is to explore if CO2 can absorb more heat. 

  1. Explain to your students that we have two jars. We will add ¼ cup of water to Jar A. In Jar B, we will add ¼ cup of water and one alka-seltzer tablet to produce CO2.
  2. Place a thermometer in both jars. You may utilize a thin metal hook to suspend it over the rim of each jar. Alternatively, you can use a string to hang the thermometer inside the jar when closing the lid.
  3. Jar A: Add ¼ cup of water to Jar A. Use a thin metal hook to suspend a thermometer over the rim of the jar. Close the lid. 
  4. Jar B: Add ¼ cup of water to Jar B, then add an alka-seltzer tablet. Quickly place the thermometer as Jar A and close the lid tightly.
  5. Heat up the jars. Place the jars in front of your heat source. Make sure the jars will all be heated evenly. 
  6. Leave the jar with the heat for 5 – 10 minutes, depending on the voltage of your heat source. 
  7. Measure the temperature of each jar and record the results. 

Summary: Ask – What do you notice about the temperature readings?  (CO2 can absorb the heat and cause temperature rise). 

For this activity, teacher could choose to either have students do lab or just demonstrate this experiment. If you choose to have student lab, you can use this Greenhouse effect lab worksheet

DP – Science Investigation

What is the greenhouse effect? (Slide 4-6)

  1. Watch the video (slide 4)
    • Summarize the content of the video. Ask students “What is the greenhouse effect?” 
    • Show student slide 5 “Global Manmade Greenhouse Gas Emissions in 2015”. CO2 is the major greenhouse gas.

  2. Argumentation task (slide 6)
    • Review CER method.
    • Students discuss in the small groups “how to respond to your friends”
    • Pick 1 or 2 groups to share with the class. Make sure that students’ responses include that the greenhouse effect is not man made. It’s a natural phenomenon that’s important to make the earth suitable for living creators. We cannot diminish it. But too much greenhouse effect causes climate change.

Time: After this activity is the suggested stop point. You can come back to the lesson tomorrow.

DP-Argumentation

Students use the CER framework to practice argumentation.

Discourse opportunity:

Class discussion and small group discussion

The significant increase of atmospheric CO2 is caused by humans burning fossil fuels to obtain energy (Slide 7-9)

Resume the lesson by asking students what caused the significant increase of CO2 from the 1800s, and what do you know would emit CO2? (slide 7)

Class discussion

Demonstration (slide 8-9）

  1. Show students the CO2 sensor. Turn it on and read the number.
  2. Light the candle, put the detector close to the candle, and read the number on the detector again. The number should immediately increase very high.
  3. Summarize: lighting the candle emits CO2.

The detector may beep when the CO2 rises. Click + button for a few seconds until it stops.)

Go through the pictures with the entire class (Slide 10 -16)

You may need to explain some of the pictures to students, such as the steel factory

 

Ask students:

  • Is the picture related to CO2 emission?
  • Is the picture related to energy?


Read the pie char in slide 17: Emphasize that CO2 accounts for about 76 percent of total greenhouse gas emissions. Most CO2 come from energy use in industry, buildings, and transportation!

Class discussion

Students generate the first version of the carbon cycle model (Slide 18-19)

Create the first version of the carbon cycle model Individually: students each create a model to show what human activities contribute to the CO2 in the atmosphere?

The class consensus model is presented in Slide 19.

DP-Modeling

 

This is the first version of carbon cycle. The model only include the three major source of human-made carbon dioxide.

Make sure that students will keep their carbon cycle model throughout the entire unit.

Information for Planning & Teaching

  • Background Knowledge
  • Lesson Timing
  • Student ideas & Experiences
  • Science Practices
  • Teaching Cases

Background Knowledge:

NA

Lesson Timing

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Student ideas & Experiences

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Science Practices

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Teaching Cases

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  • October 15, 2023