GasLab: A Domain Extensible Toolkit for Exploring Statistical Mechanics

 Gas Lab Models The GasLab project was designed to help students to visualize and explore the physical behavior of an ideal gas and relate the idealized microscopic molecular rules to the measurable observable quantities that emerge. This set of models simulates the behavior of gas molecules in a closed container under various conditions. It was one of the original CM StarLogo models (under the name GPCEE) and is now ported to StarLogoT as part of the Connected Mathematics "Making Sense of Complex Phenomena" Modeling Project. The GasLab models are examples of "extensible models". They are basic seed models that are "glass-box", allowing students to "peek under the hood" of the model and see how it works. Interested students can then modify the underlying model, creating an experiment or a new variant of the GasLab models The GasLab models are all variations of the basic model called Gas-in-a-Box. All variations use the same basic Newtonian (billiard ball) rules for what happens when gas molecules collide. Each model has different features in order to show different aspects of the behavior of gases. Many other extensions of the core Gas-in-a-Box model have been explored by students.

• ATMOSPHERE imposes a gravitational field on the gas.
• GAS IN A BOX shows the basic model and plots the speed and energy distribution in an ideal gas.
• SINGLE COLLISION shows the collision of two molecules, so that the underlying rules (conservation of energy and momentum) can be studied.
• FREE GAS removes the box walls.
• ISOTHERMAL PISTON looks at pressure, volume and temperature of a gas under a piston.
• TWO GAS has two chambers and two kinds of molecules that can mix.
• MAXWELL'S DEMON demonstrates a famous thought experiment that relates the concepts of energy and information.
• ADIABATIC PISTON has a piston with mass that can move up or down in response to its weight and the counterbalancing collisions of the gas molecules. Mechanical energy thus passes to and from the gas.

Other GasLab models available and in process:

• MEAN FREE PATH explores measuring the average distance between gas molecule collisions and how it is affected by other factors such as temperature and density.
• HEAT ENGINE combines several features to explore a heat pump moving through the Carnot cycle.