What is Geology?
Examining the earth and its composition, history, and its effects on human life is the study of geology. A geologist’s job is usually outdoors, and generally involves studying rock and soil and a host of other chemical and physical components of the Earth. In doing so, geologists are able to determine what took place in certain areas years ago that makes the scenery look the way it does today. In addition, geologists’ training allows them to foresee how the earth could change, and why, in the future.
A geologist answers questions such as how the former rock formation called “Old Man of the Mountain” came to exist on the White Mountains of New Hampshire. A geologist also studies movement and shifting of the earth that triggers landslides and earthquakes, like the one that caused the deadly tsunami in Japan in 2011.
The field of geology has several specialties. For instance, a marine geologist studies the biological, chemical, and physical characteristics of the sand on the floor of the ocean and the rock that lies beneath it. Yes, there is still lots of earth under the sea! An engineering geologist examines the rock, soil, and sediment that lies under structures like bridges, dams, high-rise buildings, and roads to ensure that the weight of those structures is being safely supported.
Examining the Soil
Soil holds infinite data on such topics as climate, people, their habitat, culture, and so much more. It is subject to pollution from agriculture, human waste, industrial by-products, and contaminants found naturally. Soil is a primary resource for production of crops and sustaining livestock. It has had a significant effect on our own human history.
A simple observation of a soil’s color reveals mineral content. For example, soil high in iron is usually a reddish color. More important, however, is that geologists will study the red soil for further clues as to how that iron got there. Texture indicates a soil’s ability to retain water and support plant, animal, or human life. The decayed matter within it also points to life that it previously supported.
Earth, Rocks and Landforms
Geologists study how the atmosphere has influenced the shape and composition of the land formations that we have today. For example, take a look at a globe. Now, look closely at the shape of the continents. Compare South America’s east coast with Africa’s west coast. Do they look as though they could fit together? Now, compare North America’s coast with the coasts of Asia and Europe. Through fossil studies, geologists know that the plant and animal life that lived along South America’s east coast also lived along Africa’s west coast. And likewise, the animal and plant life along the coasts of Europe are the same as those that lived along the North American coasts. What could this mean? That possibly, at one time hundreds and hundreds of years ago, all of the continents may have been joined as one VERY large land formation. And possibly, with time and other influences, pieces of that large land formation began to break off and separate into what we know today as the world’s 7 very distinct and separate continents.
The Earth Inside Out
The earth is many, MANY miles thick, but yet to a very good degree, scientists are able to tell us what the core of the earth is made of. They have never been able to see it, however, because it’s just too deep to try to get to by digging. But studying seismic energy, which is produced by events such as set-off explosions, or earthquakes, conclusions can be made as to the composition of the earth’s center. For instance, by looking at seismic waves that become short, long, slow, or fast, geologists use their expert training to determine the make-up of the earth at the core. Studying the earth’s magnetic field is very telling, as well. Readings that geologists analyze with various instruments help them determine further composition of the mantel, or red-hot liquid rock deep beneath the earth’s surface.
An Introduction to Erosion
Erosion is the wearing away of coastal lands from things like weather. Have you ever watched TV news reports after a hurricane, say, in South Carolina? The force of winds that are more than 100 miles an hour creates dangerous, high waves that slam against the shorelines. As a result, some of the sandy shoreline itself is washed into the ocean and eventually falls to the ocean floor.
If you’ve ever gone camping or walking in the woods, you may have come upon large rocks with very smooth surfaces. How do rocks get so smooth? You might also take a look outside your home the next time it rains. Ask your parents where your roof’s gutters meet the ground, and you might see that the ground has worn away a bit from the force of rain water continuing to flow in that very spot.
These are forms of erosion. When it happens on a much larger scale, and it does, portions of our landscape flow into a stream due to rains, or continuous, gusty winds eat away at rocks and land.
Illinois State Geological Survey
K-12 Lesson Plans
Minerals and Rocks
For 6th Grade Teachers
The Changing Landscape
Activities in Earth Science
Puzzles, Word Searches, Games
Learn About Earthquakes
All About the Earth
Mining our Minerals
Quizzes / Worksheets
History of the Earth
Q & A on Southern Nevada
Earth Science Resources
Fossils Tell Stories
Intro to Paleontology
The Dynamic Earth
Kids & Rocks