Gas

Gas

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Gas

Language: English
Description: This lesson allows the student to model a gas as a system of light circular solid objects kept in a container. This simple system can be used to gain understanding of abstract yet common concepts like pressure, temperature, heat conduction and insulation.
Target: Key Stage 3
Category: Exercise, Laboratory
Discipline: Fluids and gases, Thermodynamics
Learning objectives:
  • Build a mental picture for temperature, heat and pressure based on particle system
  • Understand isolation and heat conduction through the particle model
  • Make prediction, setup a simple test and evaluate the results
In class: Discuss what makes a balloon expand when you blow it up. Why is it difficult to compress the balloon. Ask if anyone has experience of what happens if you bring the balloon into a cold environment? What happens when it is brought back to a warm environment? This applies also to solids, although the particles are more tightly coupled. Discuss also the phenomena of heat conduction, e.g., how heating one end of a metal spoon eventually results in a raised temperature at the other end. Discuss strategies for isolat- ing the handle of the spoon from its head.

Discuss how this can be visualized and explored in Algodoo. Let the students create scenes in Algodoo using the suggestions you came up with together or let them use their own ideas. Help the students make decisions and ask guiding questions.

Encourage the students to follow the procedure Create – Predict – Interact - evaluate.

Allow the students to follow-up and share their experiences in class after the simulation.

Steps in Algodoo


Create a scene

Create a container made of four fixed walls and a movable inner wall. Create a circular particle and give it a light mass. Set the restitution (bounciness) of the walls and particle to 1. Make copies of the particle to fill the container.
  • * It is practical to turn gravity off in this lesson.
Gas container.png


Make a prediction

What happens to the gas as you move the wall towards one of the side-walls? One of the gases is now heated to a higher temperature. What effect does the gas have on the movable wall if you let it go? What will happen if the inner wall is deleted?


Run/interact

Run the simulation and interact with it.


Evaluate

Observe that the heated gas pushes the movable wall - as do particles inside a balloon. After the inner wall is removed, observe how the high velocities are being redistributed from being focused to one part of the container to become evenly distributed. This is heat conduction. The result is an even temperature. Based on these observations, how can an insulating wall be realized in reality? Try to replicate this in the simulation.


A solid can be modeled as system of particles connected by springs in a regular pattern. If you have time - model this as well and study its behaviour. You may observe both thermal vibrations and collective waves (sound waves).