The atmospheric recycling of water is a very important phenomenon on the globe because it not only refreshes the water but it also redistributes it over land and oceans/rivers/lakes throughout the globe. This is made possible by the solar energy intercepted by the Earth. The half of the globe facing the Sun, on the average, intercepts1 1.74×1017 J of solar radiation per second and it is divided over various channels as given in Table 1. It keeps our planet warm and maintains its average temperature2 of 288 K with the help of the atmosphere in such a way that life can survive. It also recycles the water in the oceans/rivers/ lakes by initial evaporation and subsequent precipitation; the average annual rainfall over the globe is around one meter. According to M. King Hubbert1 the amount of solar power going into the evaporation and precipitation channel is 4.0×1016 W. Students can verify the value of average annual rainfall over the globe by utilizing this part of solar energy. This activity is described in the next section.

Topics
Solar energy, Thermodynamic states and processes, Thermodynamic properties, Hydrology, Atmospheric radiation, Education, Industry, Scientific society and organization
1.
M.
 
King Hubbert
,
“Outlook For Fuel Reserves,”
 
Encyclopedia Of Energy
, Edited By
Daniel N.
 
Lapedes
 (
Mcgraw-hill
,
New York
,
1976
), Pp.
11
–
23
.
Google Scholar
 
2.
Alexis
 
De Vos
,
Endoreversible Thermodynamics of Solar Energy Conversion
(
Oxford University Press
,
Oxford
,
1992
), p.
22
.
Google Scholar
 
3.
Raznjevic
 
Kuzman
,
Handbook Of Thermodynamic Tables And Charts
(
Hemisphere
,
Washington, D.C.
,
1976
), P.
105
.
Google Scholar
 
4.
David
 
Halliday
 and
Robert
 
Resnick
,
Fundamentals of Physics
(
Wiley
,
New York
,
1988
), Appendix C.
Google Scholar
 
5.
Ven Te
 
Chow
,
David R.
 
Maidment
, and
Larry W.
 
Mays
,
Applied Hydrology
(
McGraw-Hill
,
New York
,
1988
), pp.
5
, 19.
Google Scholar
 
6.
“Most Annual Rainfall,”
Guinness World Records.
7.
Priit J.
 
Vesilind
,
“Parts of Chile's Atacama Desert haven't seen a drop of rain water since recordkeeping began. Somehow more than a million people squeeze life from this parched land,”
 
National Geo. Mag.
(August
2003
).
Google Scholar
 
8.
Global
 
Weather
 and
Climate
 
Extremes
,
World Meteorological Organization
, http://wmo.asu.edu/ (Retrieved on Sept. 30,
2013
).
Google Scholar
 
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2013
American Association of Physics Teachers
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