Trapping Heat with Carbon Dioxide

Introduction
In this activity students will investigate the heat trapping ability of the greenhouse gas carbon dioxide.

Credits
Activity developed by AirWaterGas Teachers-in-Residence Trey Griffin and Tracy Ziettlow based on an activity by Davies and Blakeney and a NASA Climate Change Inquiry Lab.

Grade level: 6-8

Time Required
Two class periods (45-60 minutes)

Learning Goals

  • Students will learn that carbon dioxide is a greenhouse gas and has the ability to trap heat.
  • Students will learn that the concentration of carbon dioxide in the air affects temperature.
  • Students will graph data to evaluate the connections between carbon dioxide concentration and temperature.

Lesson Format (Content):

  • Hands-on activity to collect data
  • Reading to gain background knowledge.
  • Analyzing data and interpreting results.

Standards (Next Generation Science Standards)

  • MS-PS3-3 Apply scientific principles to design, construct, and test a device that either minimizes or maximizes thermal energy transfer.
  • MS-ESS3-5 Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century. 

Materials

  • (3) Two-liter clear plastic bottles
  • (3) Laboratory thermometers (or temperature probes)
  • A heat lamp (100 W or higher)
  • (3) Alka-Seltzer tablets
  • Water
  • Timer or stopwatch
  • Rubber stopper with a hole that can fit inside the mouth of the 2-liter bottle.
  • Copies of the Activity Sheet for students

Preparation

  1. Insert the thermometers into the rubber stoppers before class.
  2. Label the lower part of the bottles 1, 2, and 3.

Introduction
Have students read the following short articles from UCAR before class.

Review the main points from the readings. Tell students that in class they will explore whether carbon dioxide can really hold heat.

Directions

  1. Place the three clear plastic bottles half-filled with water on a table. Tell students that the air in each bottle is a model of the atmosphere. Insert the stopper into each bottle so that the end of the thermometer is approximately 1” above the water line and is measuring air temperature inside the bottle.
  2. Wait a few minutes to allow the thermometers to read the air temperature inside the bottle as this is the baseline temperature.
  3. In bottle # 1, place 1 Alka-Seltzer tablet into the water and cork the bottle with the stopper. In bottle #2 place 2 Alka-Seltzer tablets and cork the bottle with the stopper. In bottle #3, leave only water and air. Allow 5 minutes for the Alka-Seltzer tablet to release all of the CO2. During this time, have students make observations of the bottles as the Alka-Seltzer fizzes. Students should notice that Alka-Seltzer causes bubbles to appearing in the water. Explain that the tablets release carbon dioxide bubbles. This is raising the concentration of carbon dioxide in two of the bottles.
  4. Have students write a hypothesis about what will happen when the bottles are put in front of a heat lamp.
  5. Place the bottles in front of a heat lamp for 20 minutes recording the temperature every minute. Make sure that the heat lamp is an equal distance from each bottle.
  6. Have students take temperature readings each minute on all three bottles. Have students record the readings in the table on their activity sheet.
  7. After 20 minutes turn off the heat lamp and allow the bottles to cool for 10 minutes. Take a temperature reading on the three bottles every minute and record.
  8. Have students use the data to make a graph of temperature readings vs. time for the three bottles and use their graph to answer the questions on the Activity Sheet.
  9. Discuss the results and the conclusions as a class.
  10. To extend learning and connect this experiment with the impacts of climate change, Have students watch the National Geographic video of the effects of a two degree rise in temperature (15 minutes) and discuss as a class.

Assessment
Formative: Use inquiry questioning to guide student understanding of the effects of carbon dioxide levels on temperature.
Summative: Have students will be able to present and discuss their findings as well as the limitations of this model.