20.3 Graphing Stories

This activity is from the Sourcebook for Teaching Science.

In 1958 C. David Keeling[i] of the Scripps Institution of Oceanography started recording the atmospheric carbon dioxide levels at the Mauna Loa Observatory in Hawaii. His work was later adopted by the National Oceanic and Atmospheric Administration (NOAA), which continuously plots carbon dioxide data year-around. The graph of this data (figure 20.8)[ii] tells one of the most important stories in science. The spreadsheet of this data is available online [sciencesourcebook.com, or search Mauna Loa carbon dioxide graph].

Hawaii is in the middle of the Pacific Ocean, far from other population centers. It is therefore a good location for monitoring global atmospheric change. Note that there are predictable seasonal variations (the small teeth on the graph) and a definite trend of increasing carbon dioxide concentration. In the forty years between 1966 and 2006, the average yearly atmospheric carbon dioxide concentration increased from approximately 320 ppm to 380 ppm, an increase of nearly 20%! Carbon dioxide is known to capture infrared radiation and retain heat. The picture in graph 20.8 tells an interesting and worrisome story. If carbon dioxide concentration continues to increase, and since carbon dioxide traps infrared radiation, then global temperatures can be expected to rise. The rapid increase in carbon dioxide, and the resulting rapid change in climate may cause great problems for agriculture and natural ecosystems. Figure 20.8 tells the story of the main cause of global warming - the increase in atmospheric carbon dioxide concentrations that results from the burning of fossil fuels (coal, natural gas, and petroleum) and the removal of vegetation which consumes carbon dioxide (deforestation, desertification).

Figure 20.8 tells a story that is being read by scientists and politicians worldwide. Graph reading and interpretation are an important aspect of literacy. One cannot understand the financial, weather, or sports sections of the newspaper without being able to interpret statistics and graphs, much less scientific and environmental stories like that told by figure 20.8. In this activity you will learn how to recognize stories in graphs, and create stories from graphs.

Activity 20.3.0 Recreate the Carbon Dioxide Graph

Activity 20.3.3 – Creating graphs from stories

Draw graphs of each of the following stories. Analyze the story, select the appropriate x-axis (independent variable) and y-axis (dependent variable), and plot a rough graph. Upload your drawings to the class Dropbox.

(1) Dribbling a basketball.

(2) Traveling up the lift hill and down the first drop of a roller coaster.

(3) Money is placed in the bank at a constant rate of interest.

(4) A thermostatically controlled air conditioner is turned on in a warm room.

(5) The movement of bridesmaids in a wedding march.

(6) The height of grass of a well-maintained lawn during growing season.

(7) The radioactive decay of the unstable isotope, uranium-238.

(8) A trumpet player practicing his or her scales from middle C to high C and back twice.

(9) The speed of an orbiting spacecraft.

(10) The population growth of mice introduced to a very small island. The population is ultimately limited by the food supply.

[i] Keeling, C., Bacastow, R., Bainbridge, A., Ekdahl,C., Guenther, R. and Waterman, L. (1976). Atmospheric carbon dioxide variations at Mauna Loa Observatory, Hawaii. Tellus, vol. 28, 538-551.

[ii] National Oceanic and Atmospheric Administration. (2007). Atmospheric Carbon Dioxide at the Mauna Loa Observatory. Earth System Research Laboratory, Global Monitoring Division. Retrieved May 1, 2007 from http://www.esrl.noaa.gov/gmd/ccgg/trends.