Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What do isobars represent on a weather map?

1. Constant temperature

2. Constant pressure

3. Constant humidity

4. Constant wind speed

The correct answer is: Constant pressure

Isobars represent lines on a weather map that connect points of equal atmospheric pressure. By plotting these lines, meteorologists can visualize areas of high and low pressure, which are crucial for understanding weather patterns and predicting changes in the weather. The spacing of the isobars indicates the pressure gradient; closely spaced isobars suggest a steep pressure difference, leading to stronger winds, while widely spaced isobars indicate gentle pressure changes. In this context, the other options do not accurately describe what isobars represent. Constant temperature would relate to isotherms, which are different lines on a weather map. Constant humidity would be represented by lines called humidity contours or isohumes. Likewise, constant wind speed is depicted through isopleths, which show areas of similar wind velocities. Therefore, understanding isobars as indicators of constant pressure is essential in meteorology for interpreting weather data effectively.