Chapter 1 - Lesson 2 Streams and Rivers, Lakes

Chapter 1 The Earth’s Bodies of Water

• Water covers more than 70% of the Earth• Water is in the ground and in the air we

breathe• People, Plants, and Animals all need water

to live

Streams and Rivers page 26

Weathering - is the process of breaking up rocks into smaller pieces called sediment

• Streams are bodies of water that flow over land in a channel

• Most streams begin on high ground, among hills or mountains

• The sources of a stream usually consist of melting snow/ice or an overflowing lake

• At the end of a stream is the mouth which empties into another body of water

Streams and Rivers

• Streams can be as small as a shallow brook• Or as large as a river, the largest and most

important streams• Most rivers form from many smaller streams

coming together, these are called tributaries

Streams and Rivers

Tributaries – are streams or rivers that flow into a larger stream or river

• The more tributaries that empty into a river the larger the river grows

• Together the river and its tributaries are called a river system

Streams and Rivers

River System – a river and all of its tributaries

• Each continent, except Antarctica, has major rivers and river systems.

• Africa has the Nile, Asia has the Yangtze, Australia has the Murray, Europe has the Danube, North America has the Mississippi, and South America has the Amazon

Streams and Rivers

• The Nile is the Earth’s longest river, it flows from Central Africa to the Mediterranean Sea

• The Amazon is the Earth’s largest river, carrying more water than the Mississippi, Nile and Yangtze combined

• River Systems carry or drain water away from the land around them (drainage basin)

• Rivers are important for many reasons including drinking, cleaning, travel and trade

Streams and Rivers, Lakes

Drainage Basin – Land drained by a river system

Streams and Rivers

Drainage Basin

• Why did many of the world’s first settlements form along rivers?

(pg.27)

• Lakes are bodies of water surrounded by land• The word lake comes from the Greek language meaning

hole because most lakes are holes in the Earth that fill with water

• Lakes exist on every continent except Antartica• The greatest amount of lakes exist where there was once

many glaciers such as North America and northern Europe

Lakes

• During the last Ice Age, glaciers gouged huge holes in the Earth and the holes filled with the water from the melted glaciers

• Lakes also form where rainwater collects in huge holes made in other ways

• Crater Lake in Oregon was formed in a crater of an extinct volcano

Lakes

• Lake Baikal in Russia is the deepest lake on Earth measuring 5,315 feet deep it was formed in a huge crack in the Earth’s crust called a rift

Lakes

Rift – a long and deep crack in the Earth

• North America has the most lakes out of all of the continents

• The largest of the North American lakes are the Great Lakes• One fifth of all of the fresh water on the Earth’s surface is

found in the Great Lakes

Lakes

H – Huron

O – Ontario

M – Michigan

E – Erie

S – Superior

• There are some large bodies of water called seas that are actually lakes• The difference is that they are not fresh water, but salt water and that is why they are called seas instead of lakes• The Dead Sea, Sea of Galilee, and the Caspian Sea are lakes• The lowest lying lake is the Dead Sea between Israel and Jordan• The highest lake is Lake Titicaca in South America

Lakes

Lakes

The Dead Sea

Lakes

Lake

Titicaca

• Not all lakes are made by nature• Some are man-made and are called resevoirs• People build dams to control river flooding or to generate

electricity

Lakes

Reservoir – a lake that forms behind a human made dam

Terms to Know• Reservoir

• Rift• Drainage basin

• River system• Tributaries

• How did Ice Age glaciers form lakes in North America and Europe? (pg. 28)