Item WC091002: Clouds are likely to form as air moves up over a mountain because air cools as it rises and clouds are likely to form as air cools.

In the diagram below, warm air is moving over a lake and upward along the side of a mountain.

Where in this diagram are clouds more likely to form: over the lake or over the mountain?

  1. Over the lake because the lake is a source of water vapor for the moving air, and clouds always form close to where water evaporates
  2. Over the mountain because clouds often form on mountains, not because the air is cooler on the mountain
  3. Over the mountain because air can become cooler as it moves up the side of a mountain, and clouds often form as air cools
  4. Clouds do not form in air that does not already have clouds. For it to be cloudy somewhere, existing clouds must move to that place from somewhere else.

Distribution of Responses

Chart showing distrubtion of responses for Item WC091002

Percent of students responding correctly

Grades 6–840%
Grades 9–1250%
Primary Language is English44%
Primary Language is not English40%

View data table