Water and Earths Surface: Intro to Hydrosphere

In this unit, you will be introduced to Earth's water. You will define the hydrosphere and identify freshwater and ocean water. The water cycle will be described, and different forms of precipitation will be identified. Earth's oceans will be explored, including the ocean zones and the life supported within them. You will explore the ocean floor to identify its major features and see how it is mapped. You will also complete a project that explores the different careers in Earth science and identify the one that you would most like to become.

This unit contains one quiz and one project.

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As you begin the unit, Water and Earth's Surface, explore the following questions for a preview of the knowledge you will use as you learn about the hydrosphere. In this unit, you will identify various forms of water found in the hydrosphere, describe the distribution of water on Earth, and recognize that a majority of it is in the oceans, while smaller amounts are freshwater and frozen in polar ice caps and glaciers.

It is okay if you do not know all the answers. Just try your best.

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Knowledge Check

Phases of Water:

water can exist as a liquid, ice, or vapor

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Vocabulary

Lesson 8.1

Water covers most of Earth's surface. In fact, water covers nearly two-thirds of Earth. So, it may seem like Earth has a lot of water. It does, but perhaps not as much as you think.

Imagine that you could take all the water on Earth and turn it into a giant sphere of water in space. Then, place the sphere of water next to Earth. This would result in a giant ball of water. All the water on Earth's surface would form a sphere 860 miles (1,384 kilometers) in diameter. Earth has a diameter of 7,918 miles (12,743 kilometers). Even its moon is 2,159 miles (3,475 kilometers) in diameter. So, the ball of water would be much smaller than Earth and even Earth's moon.

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Earth's hydrosphere contains all of its water. About 71 percent of the Earth's surface is covered by water. However, the hydrosphere is not a continuous layer of water. It includes water in the atmosphere, oceans, and on and under the ground.

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The hydrosphere is made up of all the water on Earth and includes all three phases of water. The phases of water in Earth's hydrosphere are liquid, solid, and vapor. Liquid saltwater is found in the oceans while liquid freshwater is found in lakes, rivers, and streams. Glaciers, icebergs, and polar ice caps are solid forms of freshwater. Water vapor is a gaseous form of water that forms when water evaporates into the air.

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Liquid Saltwater

​​Liquid Freshwater

Solid Water

Water Vapor

The vast majority of Earth’s water is in the ocean. Around the north and south poles and in some mountainous regions on Earth, large ice sheets and glaciers cover land and parts of the oceans with ice that exists throughout the year

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Distribution of Earth's Water

Saltwater makes up 97.5 percent of all the water on Earth. About 2 percent of Earth's water is frozen in glaciers. When the glaciers melt, this freshwater flows through rivers into the oceans, mixing with saltwater. Only about 0.5 percent of Earth's water is found in lakes, rivers, underground, and the atmosphere. Water is constantly moving on to different locations from each of these places.

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Liquid and frozen water form about 3 percent of Earth's total hydrosphere. Immediate access to groundwater and the polar ice caps is limited. Liquid water, such as lakes and rivers, allows humans to use it immediately. Rain and snow refresh the sources of freshwater.

Distrubution of Freshwater

​Glaciers and icebergs are found in Greenland, Antarctica, and the Arctic regions. Melting glaciers release freshwater. People who live near glaciers depend on the ice sheets as a source of freshwater.

Frozen Water

​Water is absorbed and stored in layers of rock. The amount of groundwater is affected by precipitation. Groundwater often supplies water to lakes

Ground Water

Surface water accounts for less than one percent of Earth's freshwater. Plants, animals, and humans depend on rivers and lakes for freshwater.

​​Surface Water

In the atmosphere, freshwater evaporates to form water vapor. Winds circulate water vapor, which forms water droplets to make clouds, around Earth. Living things depend on water vapor to bring rain and snow.

Water Vapor