2 Atmosphere, Air, and Gases
2.2 What Makes a Gas... different?
2.3 Our Atmosphere
2.5 Gas Laws
2.6 Partial Pressure
2.7 Reaction Stoichiometry and Gases
2.8 Air Pressure and Elevation
2.11 Al Kane
2.12 Density of a Gas
2.13 STP and more
2.42 Learning Outcomes
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Although we generally are mostly concerned with the layer of the atmosphere that we live in, there are other components further up that have vastly important contributions to our safety and health. It is a good idea to have a basic understanding of the strata of our atmosphere. There is even a fairly straight forward way of taking data and noticing that there are definite boundaries as you progress ever upward to outer space from the surface of our planet.
One method going way back and still used today are weather balloons that can go incredibly high and can take in data for us to utilize. One of the first sets of data was just a simple temperature probe to track temperature vs altitude. Below is a rough plot of how temperature changes with altitude for our atmosphere. You can SEE the changes in temperature profiles as you rise and these are the basis of our different atmospheric zones or strata.
Take a look at the plot and notice the 3 definite reversal spots on the plot. Where the temperature decrease stops and reverses to become a temperature increase and vice versa. In the zone we live in nearest the surface, the temperature steadily decreases as the altitude increases. This is very close to a linear function in that there is about a 6.5 °C drop in temperature for every 1000 m in rise (or 1 km). This goes until about 11 km when the temperature just stops changing. It pauses as a matter of fact and holds fairly steady at around -55 °C until around 20 km. At that point the temperature begins to rise again steadily until the next pause at close to 0 °C. Then another decrease run till way up at around 86 km where the last pause is.
Those pauses are the dividing lines between the troposphere, the stratosphere, the mesosphere, and the thermosphere. The pause regions are even named as well - the tropopause, the stratopause, and the mesopause. The following plot/figure shows these layers on top of the temperature plot from above. Both kilometers and miles are given for altitude. The numbers shown for altitude are those in the middle of the pauses where one region changes into the next. There is a discontinuity of the altitude because the exosphere starts at 600 km.
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