Page 257 - NS-2 Textbook

252 NAUTICAL SCIENCES

to tables developed for that pmpose. From the table, the jet stream, and why are these studies important?
relative humidity and dew point can be read easily. 9. Why do modern commercial aircraft prefer to fly
Aboard ship, sling psychrometers are often used to speed mostly in the stratosphere?
up the process of getting accurate wet- and dry-bulb 10. What visual phenomenon occurs in the ionosphere
readings. A handle and chain are attached to a psy- over the polar regions?
chrometer and the apparatus is whirled around in order 11. What is the importance of the ionosphere to com-
to rapidly bring the wet bulb into contact with a greater munications?
volwne of air. Using a steady, 81mv S'iving, the whirling is 12. A. What is the average air pressure at sea level?
continued until no further change can be detected in the B. What instrunlent measures air pressure?
wet-bulb reading. Then the table is referred to. III 13. What are two types of barometers used by the Navy?
14. What is weather?
15. What three things cause changes in the weather?
16. What is the "greenhouse effect?"
17. A. What are the two most widely used temperature
CRITICAL THINKING
scales?
1. Over the last decade there has arisen much debate B. What are the freezing and boiling points of each?
over the effect of modern industrial gases on the pro- 18. What is the water cycle?
tective upper layers of Earth's atmosphere. What are 19. What is the dew point?
thought tD be the major changes taking place, and 20. Wllat instnunent measures relative humidity and
what potential or actual effects are these having on dew point?
Earth's population?
2. Most present-day dermatDlogists urge the application
Temperature Conversion Problems
of sun block lotion whenever prolonged exposure to
sunlight is expected. Research why this concern has 1. Do the following conversions:
arisen and what the eventual effects might be of pro- A. 122 degrees F _ degrees C
longed tmprotected exposure to sunlight during the B. 86 degrees F _ degrees C
teenage years.
C. -4 degrees F __ degrees C
3. What wavelengths of light are referred to as the "tan-
D. 104 degrees F _ degrees C
ning rays," and ""hat can be done to minimize the
damage these might cause to a person's skin and eyes? 2. Do the follo\ving conversions:
A. 60 degrees C = _ degrees F
B. 20 degrees C __ degrees F
Study Guide Questions C. -10 degrees C _ degrees F
1. What are the hvo main elements in our atmosphere D. 35 degrees C __ degrees F
and the approximate percentages of each?
2. What changes occur to the air as one ascends into the Vocabulary
atmosphere?
3. Where does most of Earth's weather occm? atmosphere ionization
4. What are the five principal layers of Earth's atmo- humidity barometer
sphere? troposphere millibar
5. A. In what layer of the atmosphere are most clouds stratosphere isobar
found? tropopause an' nlass
B. What are the laws of gases that apply to the de- ionosphere precipitation
velopment of clouds? chemosphere insolation
6. Why have the United States and several other coun- mesosphere Celsius
tries studied Antarctic air masses in recent years? thermosphere Fahrenheit
7. A. What is the tropopause? ozone layer relative humidity
B. Why is it so important to commercial aviation? convection psychrometer
8. What are some of the current studies concerning the dew point jet stream