What are the numbers and classes?
The Dewey classification system is divided into 10 main classes
and subclasses which cover all knowledge. The basic classes are
organised by disciplines or fields of study.
At the top of each GEO. web page you will find those Dewey classes and subclasses which are important to earth and planetary science. Clicking on one of the numbers will take you to a more detailed classification with selected information resources.
Have a look at this explanatory picture of the main features of a typical GEO. web page.
If you want more information on the Dewey system, an online summary and further details are available from the copyright holder.
How do I know which class is best to
For most classwork and projects this will not be a problem. The classes and their heading names give you a good idea of what you will find there. Thus when you choose "550 Earth sciences ", you will find subclasses such as "volcanoes", "earthquakes", "climatology and weather" and so on. If you are looking for straightforward geological information resources on such things, then you will find them here. However, you will also find information in other classes. For example, the environmental effects of volcanic eruptions may be included in "360 Social services,associations - 363.7 Environmental problems." In a similar way, you can expect to find information resources dealing with the space probe flights classified not only in "520 Astronomy and allied sciences" but also in "600 Technology", "620 Engineering and allied sciences" and in several other classes depending on the nature of the research experiments on board (e.g. biology).
What if I don´t find anything of
use to me at the first try?
From anywhere within the classified links you can go back to the top and choose a new class. You should do this anyway. You can also go directly to alternate ways of finding resources from anywhere within the classified links. These include "specialised resources", "search" and "library resources".