There are several ways in which we scientists
know about the earth.
The easiest part of the earth to learn about is
the crust, because we can go right outside our
door and see it!
Geologists (scientists who study rocks) get
their best information from mapping rocks.
Rocks are our biggest insight into earth
processes. For example, by looking at volcanic
rocks we can decide what the lava below the
earth's surface contains.
A hydrogeologist's best data are measurements
from rivers and water wells, to have a better
understanding of our water resources.
A soil scientist's best way to learn about
the earth is by digging holes, analyzing the
soil, and mapping out where we find the best soils
for growing plants.
A modern technology we use is satellite data. For
example, we can use satellite data to track
exactly how many centimeters the San Andreas Fault
moves each year.