Ideas for Teaching |
Graphing DataPage 1 | Page 2 | Page 3 | Page 4 IntroductionVisual display of data, such as in a graph, can sometimes provide a much clearer picture of a problem or a trend. This concept was dramatically illustrated in Edward R. Tufte's Visual Explanations in his discussion of the Space Shuttle Challenger accident. Recall that the Challenger blew up shortly after take off from NASA's Kennedy Space Center because an o-ring failed. Tufte looked over the information published about the event, including the slides the engineers showed the night before the decision was made to launch. The concern was what the behavior of the o-rings would be in the cold temperatures forecast for the following morning. Previous tests did not include conditions as cold as the forecast temperatures, and the engineers did not show all the data they had. Tufte found additional o-ring data from reports that had not been included and started looking at it. He decided to come up with a "damage index" that he created, a number based on temperature, erosion incidents and blow-by incidents. He then graphed his damage index vs. temperature and a trend immediately jumped out where it had previously been difficult, if not impossible, to percieve. [See pages 39-52, Visual Explanations, Edward Tufte, Graphics Press, Cheshire, CT.] An additional, compelling example is included in the book - the mapping of incidents of cholera in 1854 by John Snow (pages 27-37). On to page 2 and a weather application....
Last updated:
March 26, 2002 |