Air Simulation
Grade Levels
K - 3
Time
30 to 50 minutes or so, depending on level of discussion and inclusion of optional
topics.
Purpose
To simulate the basic composition of air and various associated large and small scale
physical phenomenon such as diffusion, heat, condensation and concentration.
The lesson is important for building a foundation for other lessons regarding matter
and its fundamental units, air and its properties, and air pollution concepts.
Background
Air is not empty space. It is made of matter—mainly different types of gases. The
normal composition of air is about 78% nitrogen (N2), 21% oxygen (O2), and 1% other
gases such as argon (AR), carbon dioxide (CO2), methane (CH4), and helium (He). The
gases are comprised of molecules that are made up of atoms, the fundamental units of
matter. Air is essentially a layer of trillions and trillions of gas molecules.
Air also contains solid particles (e.g., dust, soot, ash, etc.), water droplets, and
ice crystals. These materials are also comprised of molecules that are made up of atoms.
However, these materials are not considered part of the normal composition of air.
Nevertheless, collectively, air is made up of matter such as gases, solid particles,
water droplets, and ice crystals. All matter occupies space and has weight.
The molecules that comprise air are not static (they move). On a molecular level,
they vibrate, rotate, and randomly travel about bumping into other gas molecules. The
molecules of a hot gas have more energy than those of a cold gas and travel faster and
collide harder with other molecules. Winds are the large scale movements of air
molecules in response to pressure gradients established by differential heating of the
earth's surface.
The layer of the atmosphere closest to the earth, and within which we live and breath
is called the troposphere. Within the troposphere, the various components of the air
(nitrogen, oxygen, argon, carbon dioxide, others) are well mixed meaning that the
concentration of each of the normal components of air is the same throughout. The
uniformity of the troposphere is due to mixing caused primarily by winds. On a smaller
scale, diffusion produces mixing. If several pure gases were carefully added to a
container and no mechanical mixing occurred, diffusion would result in a uniform mixture
over time as the molecules of each separate gas migrated through each other.
Objectives
Students will:
- Become air molecules
- Participate in the simulation of various physical processes associated with air.
- Composition
- Diffusion and mixing
- Heat
- Condensation
- Wind
Materials
- 4 different colors of construction paper (colors not important)
- Red: Nitrogen
- Purple: Oxygen
- Blue: Water vapor
- Yellow: Other
- Brown: Soot particle (Pollutant)
- Stapler or tape
- Scissors
Preparation
- Cut construction paper into 3 inch wide armbands in the following rough
proportions (assuming a class size of 30):
| Color |
Gas |
% in air |
# of Armbands |
| Red |
Nitrogen |
78% |
21 |
| Purple |
Oxygen |
21% |
5 |
| Blue |
Water vapor |
variable |
2 |
| Yellow |
Other |
1% |
1 |
| Brown |
Soot (pollution) |
variable |
1 |
- Place armbands around the right arms of the students. Staple or tape ends
together so armbands are snug and will remain in place on student's arms.
Activity
Composition of air
1. Have students with similar colored armbands stand together. Segregate similar
armbands into separate areas of the classroom.
2. While kids are still separated by armband type, discuss homogeneity of air (well
mixed). Contrast the well-mixed nature of air with how the kids are separated by armband
type.
3. Have the kids mix randomly and then stop.
Molecular motion and heat
4. Have the kids start walking about randomly.
5. Have the kids walk at a normal speed.
6. Have the kids slowly walk around randomly.
7. Have two kids wearing “blue” water vapor armbands stand together (maybe hold
hands)
8. Have the kids randomly walk around faster (no running).
9. Review concept of heat and molecular motion
Wind
10. Have all kids stand on one side of class room
11. Have kids all walk in one direction toward other side of class room.
Pollution
12. Ask kids to describe sources of pollution
13. Have student wearing “brown” soot particle armband raise her/his hand.
14. Ask kids if they know why air pollution is bad
15. Ask kids what they can do to reduce air pollution
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