1.2 Where rivers begin? Flashcards
A river’s ____ is its starting point.
source
How many types of river sources are there?
There are 3 main types of river sources.
What are the 3 main types of river sources?
Rain and melted snow, Springs and Lakes and glaciers.
How did the melted snow form rivers?
When rain falls or snow melts, the water flows over the surface of land and create tiny streams. These streams may join up to form rivers.
How did springs form?
Some of the water from the rain or melted snow soaks into the soil. It passe through permeable rocks until it reaches a layer of impermeable rock that will not let the water pass through it. If the layer of impermeable rock comes to the surface of the ground the water runs out the ground as a spring.
Many rivers have lake as their source.
True or False?
False
Near it’s source the river is usually above sea level and it flows very slow downhill.
True or False?
False, a river usually flows very fast downhill.
Even though it’s small, the river will get bigger and flow faster after heavy rain and lots of snow melts.
True or False?
True
How did erosion happen?
The moving water, and the sand and rocks, bump and rub against the rocks on the bottom and sides of the river, and slowly wear them away. This is called “erosion”.
Erosion cause the river to slowly form a _____ shaped valley.
a V-shaped valley
How are waterfalls formed?
A waterfall is formed when there is a section of hard rock followed by a section of soft rock along the river bed. The soft rock wears away faster than the hard rock, forming a step in the riverbed. The step forms the waterfall.
How are plunge pool formed?
The water and pieces of rock swirling around at the bottom of the waterfall wear away a hallow and forms the plunge pool.
