According to About.com, plate tectonics is the scientific theory that attempts to explain the movement of the Earth's lithosphere, which has formed the landscape features seen across the globe. It provides geology with a comprehensive theory that explains how the Earth works.
Plate tectonics affect human beings in different ways as they cause earthquakes, volcanism and mountain-building. They also induce the recycling of elements within the biosphere, and between the geosphere and biosphere. The theory states that the Earth's outermost layer, the lithosphere, is broken into seven large, rigid pieces known as plates: African, North American, South American, Eurasian, Australian, Antarctic and Pacific. Other minor plates exist which include the Arabian, Nazca, and Philippines.
The plates move in different directions and at different speeds in relation to each other, and sometimes crash together, pull apart or sideswipe each other. The place where two plates meet is known as a plate boundary, and boundaries have different names, which depend on the movement of the plate. When the plates crash, it is called a convergent boundary. When the plates pull a part, it is called a divergent boundary. When the plates sideswipe, it is known as a transform boundary. There are driving forces that contribute to the movement of the earth, such as mantle convection, gravity and the rotation of the earth.