Rapids are sections of a river where the water flows quickly and turbulently, often due to a steep gradient or obstacles like rocks. This fast-moving water creates waves and eddies, making rapids a popular spot for activities like white-water rafting and kayaking. The intensity of rapids is classified using a scale from Class I (easy) to Class VI (extremely difficult), helping adventurers choose suitable routes. The formation of rapids is influenced by various factors, including the river's slope, the volume of water, and the riverbed's composition. Rivers with significant elevation changes or rocky beds are more likely to have rapids. Understanding the characteristics of rapids is essential for safety in water sports and for ecological studies of river systems.