Hands-On, Minds-On Meteorology
Description | Programming | Operation

Lifting Air (Moist)


The Lifting Air (Moist) program allows students to view a microscopic piece of moist air and manipulate it's initial temperature, water content, and pressure (altitude) to see how the molecule's properties react.

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The primary objective is to extend and merge the understanding gained from programs Condensation and Lifting Air (Dry) to look at how water vapor can condense into tiny water droplets in the atmosphere. A secondary objective is to use the graphing tool to graph interesting relationships.




The Moist version of this program is similar to the Dry version, but instead of displaying dry air molecules, it shows only water vapor molecules (dry air molecules are invisible and can be viewed by unchecking the check box, but it is not recommended while the parcels are moving).

It is also very similar to the Condensation program, as the student can manipulate parcel temperature and humidity levels and view condensation. However, an objective here is to connect the lifting of air to the decrease of temperature required to cause condensation.

The theory behind the parcel Lifting Air (Moist) program can be found in the parcel controlling class ParcelSet*


See ParcelSet*

Graphics and Visualization

Once condensation has occurred, it is often difficult to determine how many water molecules are included in the clump, so when a condensed liquid droplet has accumulated 4 or more water molecules, a small number is placed above it.

Also, at the moment of condensation, a small quick explosion-looking image is shown and quickly disappears. These flashes represent the release of latent heat for that individual condensation occurrence.

Also See Condensation

Condensation Process

See Condensation and Water Collisions


See ParcelSet*


See ParcelSet*



Running the Program

  • Click the link for Lifting Air (Moist).
  • While stopped, select a Temperature and water content by sliding the appropriate scrollbars.
  • Once started, change pressure by sliding the scrollbar or by clicking and dragging the parcel up and down.
  • Start and Stop the molecules by clicking the appropriate button.
  • Use the checkbox to toggle the visibility of the dry air molecules.
  • This program will run better with the Dry Air molecules invisible.
  • Enable the Graphing Tool by click the appropriate button.

Extra Knowledge



Department of Atmospheric Sciences
University of Illinois at Urbana Champaign

Created by Dan Bramer: Last Modified 07/27/2004
send questions/comments to bramer@atmos.uiuc.edu