Measurement scales are standard values that can be used to compare properties. In meteorology, several scales may be used for the same quantity, depending on the purpose. For example, in the United States, temperature is frequently measured in terms of the Fahrenheit scale; in scientific use, the Celsius scale or Kelvin scale may be used instead. There are also scales for indicating the severity of the wind, hurricanes, and tornadoes.

This Reading provides background information on the underlying concepts in the Activities included in the Project Earth Science: Meteorology, Revised 2nd Edition. The Reading goes beyond what is found in the background information in the activities. The Reading can be used as supplementary information for the teacher, or to enhance classroom discussions.