GasLab Investigations

Introduction| Classroom Settings| System Requirements| Table of Contents

The set of GasLab models in StarLogoT provides a new tool for the visualization and exploration of the behavior of an ideal gas. This curriculum material is intended to guide the use of GasLab in the classroom. The target audience is high school and college students in introductory physics and chemistry, but the tool may be useful for younger or more advanced students as well.
The material is organized as a series of "Investigations" covering various interesting situations in thermodynamics. Each Investigation makes use of one or two GasLab models which have been tailored to the needs of that investigation. Note that just as the Investigation questions are closely related to each other, the models are all in the same family, differing only in the initial conditions, what is being plotted, the kind of container, and so forth. Thus the models are extensible in the same way as the Investigations: if a puzzle or a new question, one can modify the model to explore it.
The primary value of GasLab as a modeling and discussion tool is that the connection between micro-level and macro-level behavior of gases can be explicitly represented, modified, and measured. Students can develop an intuitive sense of how molecules bouncing around can give rise to the ideal gas laws and other phenomena, without complex mathematical tools. What is usually "pictured" in the mind can be watched in real time in the model. Even though GasLab uses a simplified classical collision model, one can do genuine reasoning from the level of molecular motion to many observable features of gases, such as pressure, temperature, diffusion, Brownian motion, and energy distribution.
GasLab is only one of the many science and math models that have been written in StarLogoT and are available at the Connected Mathematics website ( StarLogoT is a general-purpose object-based parallel modeling language with a low entry threshold and a high ceiling. Its use, either by writing new models or modifying and extending existing ones, is an excellent path into issues of model building in science. We hope students and teachers will want to explore the use of StarLogoT for other topics, and that this material will be an exciting starting point.

Classroom Settings

An Investigation can be used in several ways.

System Requirements

StarLogoT currently runs on Macs only. A Java-based, multi-platform successor to StarLogoT, called NetLogo, is under development.

Table Of Contents (** = completed)

Section A: Molecules bouncing around

Investigation A1**:Brownian Movement. Model:Free Gas w/ speedplot, Gas in a Box.

Investigation A2 **:Speed Distribution. Model:Gas in a Box.

Investigation A3:Elastic collisions of identical particles. Model:Single Collision.

Investigation A4:Mean Free Path ­ bridge from individual to average behavior. Model:Mean Free Path.

Section B: Pressure, Temperature, and Volume

Investigation B1**:What is pressure? Model:Gas in a Box w/Bounces.

Investigation B2 **:Pressure vs. Volume at a constant temperature. Model:Isothermal Piston.

Investigation B3:Pressure vs. Temperature at a constant volume. Model:Gas in a Box w/ Heater.

Investigation B4:Volume vs. Temperature at a constant pressure. Model:Mean Free Path.

Section C: Heat, Work, and Entropy

Investigation C1**:Free Expansion. Model:Free Expansion.

Investigation C2 :Diffusion in a Gas. Model:Two-Gas,Mean Free Path.

Investigation C3:Equipartition of energy. Model:Two-Gas.

Investigation C4:Heat engines: mechanical work to heat and back again. Model:Adiabatic Piston,Carnot Cycle ­ PV plot.

Investigation C5:Maxwell¹s Demon: a paradox in the Second Law? Model:Maxwell¹s Demon.

Section D:External Forces

Investigation D1**:Atmosphere(Gases forming an atmosphere around a planet) Model:Atmosphere.

Investigation D2 :Charged particles. Model:Two-Gas w/forces.

Investigation D3:Pressure vs. Temperature at a constant volume. Model:Gas in a Box w/ Heater.

Section E: Internal Energy

Investigation E1:What if molecules can store energy? Model:Gas w/ internal energy.

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