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6th Inquiry Activities- Greenhouse Gases, CO2, and Global Warming

The sixth-grade teachers wanted their students to delve deeply into scientific inquiry rather than just follow-a-recipe lab. Here is one example of how they interpreted the set of activities listed below.

Mr. Diaz knew that there would be some complex considerations in the creating the CO2 gas and then getting it into the bag to measure the temperature. He made CO2 it in a beaker and poured the gas over a lit candle to demonstrate that the gas is heavier than air.

The next day, he guided the class discussion to review the concepts of greenhouse gases, greenhouse effect, and global warming. Then he announced the question, "Does additional CO2 increase the temperature of air when exposed to heat and light?" He showed the students the materials they might want to use to design their lab. Then he said, "I have an idea on how to design this lab, but you might have some good ideas also. So, work with your team and see if you can design a controlled experiment to respond to our question."

Mr. Diaz walked around and listened to the groups. Soon he said, "Excuse me. I need to make a short announcement and then you can get back to your discussions. I'm hearing some good ideas. But I'm not hearing much about the control variable. What will be your control in this lab?"

A few students mentioned air, and with a little guidance, they were soon able to state, "Measuring the air in the same way we measure the CO2."

Then they got back to work. After about 25 minutes, he had the teams share the procedures that they had written on their lab sheets. All of the lab descriptions had evidence of a promising lab. For example, one team wrote:

  1. Get your beaker
  2. Mix 6 ml (1 teaspoon) baking soda and 16 ml of vinegar to make CO2
  3. Take temperature of the air in the Ziploc bag
  4. Leave the thermometer in bag and pour in CO2
  5. See if the temperature changes
  6. Record your data

Time is always a factor, so the following day, the students did the lab described below. However, next year, Mr. Diaz plans to schedule time for the students to try the labs they designed and analyze their effect.

Activity 1: Introduction

Read, discuss, and interpret: Fossil Fuels, Greenhouse Gases, and Global Warming

Activity 2: Preparation for the Lab

Demonstrate that CO2 is heavier than air

  1. Melt the bottom of a candle and set it upright in a saucer or aluminum pan.
  2. Light the candle.
  3. Measure 6 ml (1 teaspoon) sodium bicarbonate (baking soda) in a large measuring cup or beaker.
  4. Measure 50 ml (¼ cup) vinegar in another small measuring cup or beaker.
  5. Pour the vinegar into the large measuring cup containing the baking soda.
  6. As the mixture is bubbling, pour the gas, NOT the liquid, onto the candle.
  7. Since CO2 is heavier than air, the flame will be snuffed out.

Activity 3: CO2 Inquiry Lab

Compare temperature increases in CO2 and ambient air

Display the materials listed below. Ask students, "Does additional CO2 in the air increase the temperature of air when exposed to heat and light?"

After a class discussion, your students may be ready to work with their groups to design their own investigations. However, there are many technical issues in gathering the air and the CO2. The following process ensures that the temperature change is caused by the gases in the bags and not by the heat generated when the baking soda fizzes in the vinegar.

Materials for each group:
  • A table lamp, or, if you have sunny days, students can use the sun's energy. If they take the bags outside, have them lay the two bags on identical piece of cardboard or identical books – just to insulate the bags from the temperature of the concrete or soil.
  • 3 identical thermometers
  • 3 Ziploc bags – quart size
  • 1 snack-size Ziploc bag
  • 5 ml (1 teaspoon) sodium bicarbonate (baking soda)
  • 50 ml (about 1/4 cup) vinegar
  • timer
  • lab books or chart paper to record the data

CO2 .

Each group will:
  • Create a data chart with four columns labeled: Time, Ambient Air, Exhaled Breath and CO2
  • Carefully tape one thermometer inside of each zip lock bag
  • Record the starting temperature of each bag before adding the gas.
  • Swing the first bag (Ambient Air) through the air and capture the air in the room or set the bag in front of a fan. Quickly close the bag. It does not have to be completely filled with air
  • One student exhales into the second bag (Exhaled Breath) and quickly seals the bag.
  • Place the baking soda into the small snack-size Ziploc bag. Place the small bag into the quart-size bag labeled CO2.
  • Carefully pour the vinegar into the SMALL snack-size bag. Leave it open. Zip closed the LARGER quart-sized Ziploc bag. (If you spill any liquid into the larger bag, you need to start over!) HOLD THE LARGER BAG UPRIGHT.
  • When the solution has finished fizzing, gently upzip the CO2 bag and remove the smaller bag with the spent vinegar and backing power solution. Seal the large bag again. (NOTE: SINCE THE CO2 IS HEAVIER THAN AMBIENT AIR, THE CO2 WILL STAY INSIDE THE LARGER BAG WHEN YOU OPEN IT TO REMOVE THE SMALLER BAG. REMEMBER TO HAVE YOUR PARTNER HOLD THE BAG UPRIGHT.)
  • Take the temperature reading for each bag and record it as the start temperature.
  • Place the bags outside, (it is okay to lay them on their side now) making sure both bags are in the same orientation to the sun on identical surfaces. OR If using sunlamps, place the bags the same distance and angle from their lamp bulb.
  • Observe and record the temperature each minute for 10 minutes.
  • After 10 minutes, turn off the lamps, or bring the bags indoors/ out of the sunlight.
  • CONTINUE recording the temperature for 5 more minutes.
  • Graph the results: Using the chart they made, students graph the results. Have them discuss in their groups what will be the best way to create the graph and enter the data. OR, they could enter the data into Excel and allow the program to create the graph.
  • Discuss the results. Unfortunately, it is difficult to capture pure CO2 in a quantity that is equal to the contents of the other bags, and the water vapor in the other gases affects the temperature. However, the graphs should show differences in how the three gas mixtures hold the heat.

NOTE: Adding a fourth bag with exhaust gases from an automobile would add an interesting comparison.

Activity 4: Interpret of the Model of the Greenhouse Effect and Its Limitations

(Students may need a review how fossil fuels are formed and used. The following website is informative and attractive. )

  • Students view the time-laps of global greenhouse gas emissions 400 years at
  • Students view YouTube clip -- Annual variation of CO2 in earth's atmosphere since 1980 at
  • EPA's website, A Student's Guide to Global Climate Change, is a valuable, interesting, and interactive source of information. Students explore the website and then they can work with their partners to make a flip book depicting the most important information about climate change.
  • Students discuss in their groups how the information from the Student's Guide and the videos about the greenhouse effect compares to or informs their model of heat retention in greenhouse gases.
Activity 5: Calculate your Global Footprint

Applying what you have learned about CO2 increases in the atmosphere.

  • Now that that the students understand a little about how our demand for energy affects the earth's atmosphere, they explore ways to reduce their use of energy. Using the Ecological Footprint Calculator from Global Footprint Network's Individual Footprint at, the students create an avatar and then show how many planets we would use up if everyone lived as they live. (Nature Conservancy also has a footprint calculator at )
  • Students brainstorm a list of 50 ways to improve air quality. Post these ideas in the room. Students place a star by one or more of the ideas that they will commit to.


  • Figure how many pounds of CO2 is produced by the family car per year. The teacher demonstrates this activity with his/her personal car. The teacher can monitor the car's mileage for one week. Then the students can help answer the question: If I drive my car 230 miles in one week, how many miles will I drive in a year? With that information, the students can continue helping the teacher do the mathematics described below. (The teacher needs to know the average gas mileage for the vehicle. Ehow has a good explanation. ). Once you know the average miles per gallon, the students can help figure the teacher's total CO2 usage. ___ Miles driven per year by the vehicle. ___ Average miles per gallon for the vehicle. Divide miles driven by miles per gallon = gallons used per year. Multiply: gallons used per year by 22 pounds = total pounds of CO2.
  • Most electric companies provide free energy saver kits.
  • Methane is the second most prevalent greenhouse gas. Population Connection has a good activity to explore Methane – Methane Matters.

6th Introduction

6th Background Information

6th Inquiry Activities