a level geography
| Front | traction |
| Back | large boulders + pebbles rolled along the river bed |
| Front | Bradshaw model |
| Back | model used to illustrate how various characteristics of a river, such as discharge, velocity, channel width, and sediment size, change from the source to the mouth of the river |
| Front | waterfalls |
| Back | often occurs where there is a difference in rock resistance: softer rock erodes more quickly than harder rock, causing the river to plunge over the edge. As the water falls, it continues to erode the base, deepening the plunge pool and gradually retreating the waterfall upstream creating a gorge |