As such, the theory can be thought of as something that connects one set of information with another. To illustrate, information in the physical sciences can generally be separated into two types. We also know that the seasons oppose each other in north and south hemispheres - when its summer in New Zealand its winter in New York. This is what we know and we need a theory to explain this. The operative theory is one involving gravitational forces and other information - planetary motions and solar radiation.
Scientists now have some very sophisticated measuring devices to produce data .
It is critical to recognize that these measurements that produce data do not in and of themselves produce understanding, they only give descriptions of the Earth, ways of quantifying its behaviour and form. These data are typically both incomplete and inexact - we do not have measurements of rainfall everywhere, for instance. It's quite difficult to determine how much rain falls over the oceans. More generally we describe a system of interest by numerous quantities - where n is large these quantities may be geophysical, geological or something else. All are included in a description of the system under study.