Water and Weather

Chapter Four: Water and the Water Cycle

•

4.1 Water on Earth’s Surface

•

4.2 The Water Cycle

Investigation 4A

The Water Cycle •

How is a model of the water cycle in your classroom like the Earth’s water cycle?

4.1 Water on Earth’s Surface

• About 70 percent of Earth’s surface is covered with water. • This water is found in oceans, rivers, lakes, under the ground, and as ice.

4.1 The hydrosphere

• All the water on Earth is part of a large system called the

hydrosphere.

• On Earth, water occurs in all three phases.

4.1 The distribution of water on Earth

• About 97% of Earth’s water is salt water found in oceans.

• If all the water on Earth could fit into a one-liter bottle, only 17 milliliters would be fresh water.

The distribution of water on Earth

4.1 Places where water is found

•

Surface water

on Earth refers to water that collects on the ground.

• This water includes oceans, lakes, rivers, streams, and reservoirs.

• A

reservoir

is a protected artificial or natural lake that is used to store water.

4.1 Places where water is found

• A

glacier

is a huge mass of ice that forms on land when snow and ice accumulate faster than they melt. • Most of Earth’s fresh water is in the form of glacier ice.

4.1 Places where water is found

•

Groundwater

is water that collects under ground. • Some of the water on Earth’s surface moves down through the soil to the

water table

(the upper level of underground water).

4.1 Water as a resource

• The temperature range on Earth’s surface is just right for water to exist in all three phases — liquid, solid, and gas.

4.1 Water as a resource

• One of the reasons why water is so useful is that it can dissolve many things.

• Water dissolves nutrients found in food, gases such as oxygen, and minerals found in rocks.

4.1 Water as a resource

• The human body is 60% to 75% water.

• When you eat food, water in your body dissolves nutrients so they can be carried through your bloodstream.

4.1 Uses for water

• Water is necessary for all forms of agriculture and farming. • For example, water is needed to grow grain for bread and to grow fruits and vegetables. • Water is also used in industry and in many ways in your home.