1.32. Scientific Graphing http://www.ck12.org
TABLE1.8: Average Number of Tornadoes in the U.S. per Month (2009–2011)
Month Average Number of Tornadoes
January 17
February 33
March 74
April 371
May 279
June 251
July 122
August 57
September 39
October 65
November 39
December 34Line graphs are especially useful for showing changes over time, or time trends in data, such as how the average
number of tornadoes varies throughout the year. Therefore, a line graph would be a good choice to display the data
in theTable1.8. The line graph below shows one way this could be done.
Q:Based on the line graph above, describe the trend in tornado numbers by month throughout the course of a year.
A:The number of tornadoes rises rapidly from a low in January to a peak in April. This is followed by a relatively
slow decline throughout the rest of the year.
Summary
- Graphs are very useful tools in science because they display data visually. Three commonly used types of
graphs are bar graphs, circle graphs, and line graphs. Each type of graph is suitable for a different type of data. - Bar graphs are suitable for comparing values for different things, such as the average numbers of tornadoes
for different cities. - Circle graphs are used to show percents of a whole, such as the percent of all U.S. tornadoes with different
strengths.