The Appalachian Mountains
Mountains form in two different ways: volcanic development or plate tectonics. Our focus is on plate tectonics. Plate tectonics is the movement of the floating crust, or plates, over the molten outer core of the Earth. The movements are so slow that they are not perceptible to the naked eye and must be measured with the help of satellites and other advanced technology.
When two plates move towards each other, they eventually “crash” together, forming soaring mountains and deep valleys. Only when the two plates stop moving towards each other do the mountains stop rising higher and higher. Currently, the continental plate where India is located is moving into the Asian plate where China is located. The result of the collision is the Himalayan Mountains. Because the two plates are still moving towards each other, each year Mount Everest gets taller and taller.
The Appalachian Mountains formed the same way. Many millions of years ago, the European and North American plates crashed together forming a long line of mountains. This happened not once, but twice over the history of the Earth. The result was one mountain chain, the Appalachian Mountains in North America and the Caledonian Mountains extending through the British Isles.
This motion is similar to two cars having a head-on collision. The steel of the cars crumples and forms ridges and valleys in the metal.
Cool Sites to look up:
Tennessee Encyclopedia of History & Culture: Geology