__________________ - When pebbles grind along the river bank and bed in a sand-papering effect.

___________________ - When rocks that the river is carrying knock against each other. They break apart to become smaller and more rounded.

__________________ - When the water dissolves certain types of rocks, eg limestone.

________________ Weathering– rainwater is slightly acidic and over time this wears away the rock.

____________________ Weathering- occurs when plants and animals wear away rocks, for example, roots growing in cracks in the rock or animals such as rabbits burrowing into rock.

physical changes causes rocks to break down, for example, a change in temperature from day to night causes rock to expand and contract and break up (eg onion skin weathering). Or, changes in temperature cause water to freeze and expand, melt and contract leading to __________________________weathering.

___________ are occasional, rapid movements of a mass of earth or rock sliding along a steep slope. They can occur after periods of heavy rain, when the water saturates overlying rock, making it heavy and liable to slide.

_________ creep is a very slow movement, occurring on very gentle slopes because of the way soil particles repeatedly expand and contract in wet and dry periods. When wet, soil particles increase in size and weight, and expand at right angles. When the soil dries out, it contracts vertically. As a result, the soil slowly moves down slope.

______________- large, heavy pebbles are rolled along the river bed. This is most common near the source of a river, as here the load is larger.

_________________________ - pebbles are bounced along the river bed, most commonly near the source.

_________________- lighter sediment is suspended (carried) within the water, most commonly near the mouth of the river.

When the river loses energy, it drops any of the material it has been carrying. This is known as _____________________.

_____________ - a small river or stream that joins a larger river.

__________________ - the point at which two rivers meet.

_______________ - the area of high land forming the edge of a river basin.

_____________ - this is where the river flows.

A _____ profile is a line representing the river from its source (where it starts) to its mouth (where it meets the sea).

A ________ profile is a cross section of a river's valley and channel.