Item CL008002: When cold air comes into contact with warmer air around it, the cold air will sink.

A teacher opens a window in her classroom, letting in air that is colder than the air inside the classroom. 

What will happen to the colder air when it comes into contact with the warmer air in the classroom?

  1. The cold air will sink toward the floor.
  2. The cold air will stay at the same height as the window, neither rising nor sinking.
  3. The cold air will sink if it is much colder than the air around it; but if it is only a little colder than the air around it the cold air will not sink.
  4. The cold air from outside will not sink toward the floor, but the coldness from the air will sink toward the floor and cool the air that is already there.

Statistics for this item are available in the Original Project.

NGSS does not address the idea that cold air sinks and warm air rises or why that occurs. It does address the role that density and temperature differences play in creating ocean currents, which is an analogous process (see Framework statement MS ESS2.C on p. 185).