In this game, students use their bodies to illustrate how temperature, density, and volume affect air pressure

Temperature affects how particles move.

As air warms up, the particles start to vibrate and bump into each other, increasing the space around each particle. Because each particle uses more space for motion, the air expands and becomes less dense (lighter).

A lower density means that there are the same number of air molecules that occupy a larger space (volume). If the temperature of air increases but the volume stays the same, the pressure will increase.

The opposite effect happens when the air cools (temperature decreases). As the temperature drops, particles move more slowly, taking up less room. The amount of space the air takes up shrinks, and reduces the air pressure.

### Objectives

• Describe the relationships between temperature, density and volume on air pressure.

• Explain how air pressure works

### Materials

• Outdoor field or large playing area

• Cones (or similar markers)

### Key Questions

• When the area decreased, how did it affect the air density?
• Does this raise or lower air pressure?
• Were there more collisions between particles when it was hotter or cooler?
• Does this raise or lower air pressure?

### What To Do

1. Place cones every 20 feet around the perimeter of the playing field. These cones represent the boundaries of the container the air particles are in.
2. The students are individual air particles.
3. Air particles (students) expand to fill the volume (area in this case) they are in, and they react to changes in temperature. An increase in temperature causes faster movement (running), a decrease in temperature causes slower movement (walking).
4. The students pretend to be air particles. Every now and then, call out changes in the temperature (e.g. hot, warm, cool, icy cold): the students must act accordingly.
5. Pause the game and gather the students into the middle. Decrease the size of the playing area by moving the cones in (mimicking a decrease in volume).
6. Repeat the game with changes of temperature.
7. Decrease the size of the field again.
8. ​Continue to shrink the field until the students can barely move.

Teacher Tip: The game can be modified into freeze tag, but where the playing area gets progressively smaller. Anyone who goes outside of boundaries becomes auto-frozen.

### Extensions

• How is this model different than how real air particles act with a temperature change?
• Can you tell if you’re surrounded by a high-pressure system or a low-pressure system by using your five senses?

### Other Resources

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From Canada, Ty was born in Vancouver, British Columbia in 1993. From his chaotic workspace he draws in several different illustrative styles with thick outlines, bold colours and quirky-child like drawings. Ty distils the world around him into its basic geometry, prompting us to look at the mundane in a different way.