Plate tectonics is the scientific theory that explains how the Earth's outer layer (the lithosphere) is divided into large pieces called tectonic plates that move slowly over the Earth’s surface.Key PointsThese plates float over the softer layer called the asthenosphere.Their movement causes earthquakes, volcanic eruptions, formation of mountains, and continental drift.There are major and minor plates, like the Pacific Plate, Eurasian Plate, and Philippine Sea Plate.Example: Kapag nagbanggaan ang dalawang plates, puwedeng magkaroon ng lindol o pagputok ng bulkan — tulad ng nangyayari sa Pacific Ring of Fire.