Water on Earth

​The Physical World

Lesson 2: Water on Earth

​Main Ideas:

1. Salt water and freshwater make up Earth's water supply.

​Main Ideas:

1. Salt water and freshwater make up Earth's water supply.

2. In the water cycle, water circulates from Earth's surface to the atmosphere and back again.

​Main Ideas:

1. Salt water and freshwater make up Earth's water supply.

2. In the water cycle, water circulates from Earth's surface to the atmosphere and back again.

3. Water plays an important role in people's lives.

Earth's Water Supply

Approximately two-thirds of Earth's surface is covered with water. There are two kinds of water: salt water and freshwater. About 97 percent of Earth's water is salt water. Most of it is in the oceans, seas, gulfs, bays, and straits. Some lakes, such as the Great Salt Lake in Utah, also contain salt water.

Earth's Water Supply

Approximately two-thirds of Earth's surface is covered with water. There are two kinds of water: salt water and freshwater. About 97 percent of Earth's water is salt water. Most of it is in the oceans, seas, gulfs, bays, and straits. Some lakes, such as the Great Salt Lake in Utah, also contain salt water.

Earth's Water Supply

Salt water cannot be used for drinking. Only freshwater is safe to drink. Freshwater is found in lakes and rivers and stored underground. Much is frozen in the ice found in glaciers, as well as the Arctic and Antarctic regions.

Earth's Water Supply

Salt water cannot be used for drinking. Only freshwater is safe to drink. Freshwater is found in lakes and rivers and stored underground. Much is frozen in the ice found in glaciers, as well as the Arctic and Antarctic regions.

Earth's Water Supply

One form of freshwater is surface water. This is stored in streams, lakes, and rivers. Streams form when precipitation falls to Earth as rain, snow, sleet, or hail. These streams then flow into larger streams and rivers. Less than 1 percent of Earth's water supply comes from surface water. Most freshwater is stored underground. Groundwater bubbles to the surface in springs or can be reached by digging deep holes, or wells.

The Water Cycle

Water is the only substance on Earth that can take the form of a liquid, gas, or solid. In its solid form, water is snow and ice. Liquid water is rain or water found in lakes and rivers. Water vapor is an invisible form of water in the air.

The Water Cycle

Water is the only substance on Earth that can take the form of a liquid, gas, or solid. In its solid form, water is snow and ice. Liquid water is rain or water found in lakes and rivers. Water vapor is an invisible form of water in the air.

The Water Cycle

Water is always moving. When water on Earth's surface heats up, it evaporates and turns into water vapor. It then rises from Earth into the atmosphere. When it cools down, it changes from water vapor to liquid. Droplets of water form clouds. When they get heavier, these droplets fall to Earth as precipitation. This process of evaporation and precipitation is called the water cycle. Some precipitation is absorbed into the soil as groundwater. The rest flows into streams, rivers, and oceans.

The Water Cycle

Water is always moving. When water on Earth's surface heats up, it evaporates and turns into water vapor. It then rises from Earth into the atmosphere. When it cools down, it changes from water vapor to liquid. Droplets of water form clouds. When they get heavier, these droplets fall to Earth as precipitation. This process of evaporation and precipitation is called the water cycle. Some precipitation is absorbed into the soil as groundwater. The rest flows into streams, rivers, and oceans.

Water and People

Water is crucial for survival. It is a problem when people lack freshwater because of shortages. Shortages are caused by overuse and by drought, when there is little or no precipitation for a long time. Water shortages can lead to less food. Another problem is pollution. Chemicals and waste can pollute water, making it dangerous to use. Lack of water can lead to conflicts when countries fight over who controls water supplies.

Water and People

Water is crucial for survival. It is a problem when people lack freshwater because of shortages. Shortages are caused by overuse and by drought, when there is little or no precipitation for a long time. Water shortages can lead to less food. Another problem is pollution. Chemicals and waste can pollute water, making it dangerous to use. Lack of water can lead to conflicts when countries fight over who controls water supplies.

Water and People

Water can affect the physical environment. For example, sinkholes are formed when water dissolves the surface layer of the ground. Heavy rains can cause flooding that damages property and threatens lives.

Water and People

Water has many benefits, too. It quenches out thirst and allows us to have food to eat. Flowing water is an important source of electric energy. Water also provides recreation, making our lives richer and more enjoyable.

Water and People

Water is essential for life on Earth. Cities and even nations are now working together to manage freshwater supplies. For example, Central Florida Water Initiative works with businesses and many other groups to protect the water resources in that region.

Multiple Choice

Some freshwater is locked in Earth's:

• Oceans

• Water Vapor

• Seas

• Glaciers

Multiple Choice

Less than 1 percent of Earth's water supply comes from ____________ stored in streams, rivers, and lakes.

• Surface water

• Trees

• Groundwater

• My water faucet

Multiple Choice

Water can be a solid (ice), a liquid, or a gas called:

• Methane

• Precipitation

• ICEE Drink

• Water Vapor

Multiple Choice

The Water brought to the surface from deep holes is:

• Freshwater

• Precipitation

• Groundwater

• Evaporation

Multiple Choice

Water that falls from clouds as rain, snow, sleet, or hail is:

• Water cycle

• Precipitation

• Groundwater

• Evaporation

Multiple Choice

Surface water is a form of:

• Freshwater

• Glacier

• Groundwater

• Evaporation

Multiple Choice

Large areas of slow-moving ice are called:

• Snow banks

• Glaciers

• Ice Cube

• Vanilla Ice

Multiple Choice

The circulation of water from Earth's surface to the atmosphere and back is called:

• Water cycle

• Water vapor

• Surface water

• Groundwater

Multiple Choice

Water that occurs in the air as an invisible gas is called:

• Water cycle

• Water vapor

• Surface water

• Groundwater

Multiple Choice

Water that is stored in Earth's streams, rivers, and lakes is called:

• Water cycle

• Water vapor

• Surface water

• Groundwater

Multiple Choice

Water found below Earth's surface is called:

• Precipitation

• Freshwater

• Surface water

• Groundwater

Multiple Choice

Water without salt is called:

• Precipitation

• Freshwater

• Surface water

• Groundwater

Multiple Choice

Water that falls to Earth's surface as rain, snow, sleet, or hail is called:

• Precipitation

• Freshwater

• Surface water

• Groundwater

Extra Credit Available!

Do a book report on the novel "The Water Knife" by Paolo Bacigalupi. You can read the book or listen to the audiobook, then either write a book report or do a presentation for the class. Doing this can help you in multiple ways: whatever grade you receive on your report will be added (not averaged) into your Daily Work score (80% of your grade). Or you have the option of skipping a test in the future and substituting your grade on the report. Let Mr. I know if you're interested.

Honors Assignment:

​Critical Thinking: Solve Problems

​

​You are campaigning for public office. Write a speech describing three actions you plan to take to protect supplies of freshwater. We will start scheduling speeches in class starting on Monday, 9/19.