NetLogo Models Library:
This model introduces the behavior of gas particles trapped in a fixed-volume container (such as a bike tire) or free and unbounded. This model is part of the "Connected Chemistry" curriculum http://ccl.northwestern.edu/curriculum/ConnectedChemistry/ which explore the behavior of gases.
Most of the models in the Connected Chemistry curriculum use the same basic rules for simulating the behavior of gases. Each model highlights different features of how gas behavior is related to gas particle behavior.
In all of the models, gas particles are assumed to move and to collide, both with each other and with objects such as walls.
In this model, the fixed volume container (represented by a box), can be drawn in different sizes and proportions. The number of particles added to the inside or the outside of the box can be changed by painting particles. And the rules of particle interactions (do they bounce off the walls? and do they collide with each other?) can be easily turned on and off).
This model helps students become acclimated to the user interface of NetLogo and evaluate modeling assumptions and representations, before they begin more analytical data analysis and mathematical modeling tasks associated with later models.
When the COLLIDE? switch is on, the particles are modeled as hard balls with no internal energy except that which is due to their motion. Collisions between particles are elastic. When the BOUNCE? switch is on, the particle will then bounce off the wall in an elastic reflection (angle of incidence equals the angle of reflection).
Particles behave according to the following rules:
Can you observe collisions with the walls as they happen (you can pendown a particle or slow down the model)? For example, do the particles change their color? Direction?
In what ways is this model a correct idealization of kinetic molecular theory (KMT)?
In what ways is this model an incorrect idealization of the real world?
Turn the COLLIDE? switch off and repeat steps 7-9 and observe the effects. Turn the BOUNCE? switch off and repeat steps 7-9 and observe the effects.
Can you "puncture" the box, so that particles will escape?
What would happen if the box were heated? How would the particles behave? How would this affect the pressure? Add a slider and code that increases the temperature inside the box.
If you could change the shape of the box, so that the volume remains the same: Does the shape of the box make a difference in the way the particles behave, or the values of pressure?
See GasLab Models See other Connected Chemistry models.
This model is part of the Connected Chemistry curriculum. See http://ccl.northwestern.edu/curriculum/chemistry/.
We would like to thank Sharona Levy and Michael Novak for their substantial contributions to this model.
If you mention this model or the NetLogo software in a publication, we ask that you include the citations below.
For the model itself:
Please cite the NetLogo software as:
To cite the Connected Chemistry curriculum as a whole, please use:
Copyright 2004 Uri Wilensky.
This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Commercial licenses are also available. To inquire about commercial licenses, please contact Uri Wilensky at email@example.com.
This model was created as part of the projects: PARTICIPATORY SIMULATIONS: NETWORK-BASED DESIGN FOR SYSTEMS LEARNING IN CLASSROOMS and/or INTEGRATED SIMULATION AND MODELING ENVIRONMENT. The project gratefully acknowledges the support of the National Science Foundation (REPP & ROLE programs) -- grant numbers REC #9814682 and REC-0126227.