Teacher resources and professional development across the curriculum

Teacher professional development and classroom resources across the curriculum

# Physical Science: Session 2

## Exploring the Model: Air

### Introducing the Model

On the next page, we show a simulation of air, where the size of the air molecules has been increased and time has been slowed down.

In order to make the particles visible, we illustrate a very small volume — the side of the box is 161 x 10-10 m (or 161 angstroms, 1 angstrom = 10-10 m). For a sense of scale, each side of the box is 1/1000 the diameter of a human hair. At the scale of the simulation, each atom is approximately the correct size, shown as 3 x 10-10 m or 3 angstroms in diameter. This simulation is set up to show what air (a gas) at room temperature would look like.

A particle in this simulation is represented as a small sphere: blue for nitrogen (78% of the particles in air), red for oxygen (21% of the particles in air) and yellow for argon (about 1% of the particles in air). When you start the simulation by clicking “run,” you’ll see an animation in which each increment is 10-14 seconds — the real particles in air move much faster.