2.04 Trends In Air Pressure

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In keeping with our look at trends and thinking about explorers, in this lesson, you will examine some data concerning relative air pressure and altitude. Then you will be reading an article that explains the relationship between air pressure and mountain climbing, climbing Everest to be exact.

Air pressure is measured using an instrument called a barometer. Mountain climbers can use air pressure readings to estimate the heights of mountain peaks. Then they can know if they need to bring oxygen with them on their climb.

This thought reminds me of an urban legend: a story about a college physics professor who asked a question on an exam concerning the use of a barometer to measure the height of a tall building. Check out this link to see some examples of "out of the box" thinking that fit pretty well with our course motto: "Its a matter of perspective."
Legend Link -- Enjoy, but come back quickly to the real lesson!

Part I: Pressure Trends
The data collected for this part of the exploration is displayed in the chart or data table below. Data tables are used frequently by scientists as a method of organizing information that they have collected. Reading data tables and charts is an important skill for you to develop. You will get some practice in this lesson. The data in the table you will examine gives information concerning the relationship between altitude and air pressure.

Explaining the Table:
Examine the data table (chart) to the right. Notice that the title of the column reveals the type of information in that column.

The column on the left shows altitude above sea level. Notice that it is in increments of 1000 feet.
The column on the right shows barometric readings in inches of mercury. This is air pressure.

Reading Data Tables
Before you begin, open and print the lesson Work File. Use it to record your work for this part of the lesson and for the Lab in Part II.
Work File

It is important to understand how to read data and information that is presented in tables. Examine the two columns in the table to the right; compare them; look for trends or patterns.

1. Based on the information in the data table, finish the following sentence (record your answers on the Work File):
"As altitude increases, the air pressure _________________."

The sentence above should describe the trend in air pressure as altitude increases or the general relationship between altitude and air pressure.

Altitude Above Sea Level in feet	Barometer Reading in inches of mercury
0	29.92
1000	28.86
2000	27.82
3000	26.81
4000	25.89
5000	24.89
6000	23.98
7000	23.09
8000	22.22

Considering Air Pressure
Visit the PBS website "Everest." There you will find a short article that discusses air pressure as an important factor in mountain climbing. In this article, you will find information about what air pressure is, what instrument is used to measure it, and how it is affected by elevation above sea level.

1. Read the article and complete the items for Task 2 on the Work File.
Resource Site: Atmospheric Pressure

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