Earth is the only planet with a large amount of liquid water.
Because of water, Earth can support life.
Water is the only substance on Earth that exists in all three physical states at normal temperature.
Water covers most of Earth.
Earth’s four named oceans are all connected to form one huge ocean that covers 71 percent of the planet’s surface.
ALL life is dependent on water.
The human body is two-thirds water.
Most rivers and lakes contain fresh water, which is not salty and has little taste.
The oceans contain salt water, which has many dissolved minerals.
Most (97%) water on Earth is salt water.
Water moves in a worldwide cycle.
Water on Earth is continuously moving from one place and form to another. This continuous movement is called the water cycle. 1 2 3 1 Condensation : Vapor changes into liquid. 2 Precipitation : Water falls to the surface. 3 Evaporation: Water rises as vapor.
The water cycle involves three processes.
Evaporation: water changes from a liquid to a gas (vapor).
Condensation: Water changes from a gas (vapor) to a liquid.
Precipitation: any form of water that falls from clouds after condensation has taken place.
The water cycle impacts our lives through precipitation, which brings needed fresh water for drinking and crops but may also cause flooding or other problems.
Section 1.2 Fresh Water Flows and Freezes on Earth
Water flows and collects on Earth’s surface.
The force of gravity pulls water downward.
When precipitation falls on a high ridge that forms a divide , it flows away in different directions.
All the water flowing downward on one side of a divide flows into a drainage basin.
Water in a drainage basin forms streams and rivers or sinks into the ground. Most water eventually flows to the sea. Much of Earth’s fresh water is frozen.
Surface water collects in ponds and lakes.
Water collects in low areas to form ponds and lakes.
Water enters as precipitation or run off from streams.
Lake = larger than pond, can’t usually see the bottom (deep).
Pond = smaller than lake, usually filled with plants.
Turnover = during winter, the cool water layers switch places with the warm layers
Turnover = during winter, the cool water layers switch places with the warm layers.
An increase of nutrient level in a lake or pond.
Caused by buildup of deadly organisms or by pollution such as fertilizers and phosphates from detergents.
Causes increase in algae in water which causes oxygen depletion in water, then the plants and animals die.
Cleveland, Wisconsin: Knee-deep algae closed down the boat landing in Lake Michigan (2002).
Most fresh water on Earth is frozen.
2/3 Earth’s water is frozen near the poles in continental glaciers .
Valley glaciers build up in mountainous areas and flow slowly down between the mountains.
An Iceberg is a piece of glacier that breaks off and floats in the ocean. Only about 1/8 of the total volume and weight of an iceberg floats above the water.
Section 1.3 Fresh Water Flows Underground
Water fills underground spaces.
Some water sinks into the ground.
Plants use some of it.
Some sinks deeper into Earth and is held underground as groundwater .
Wells draw water from the aquifer.
Water collects and moves beneath the land surface.
Either ground materials are:
Permeabl e: water can flow through them. (sandstone, sand, gravel, soil)
Impermeable : water can not flow through them. (water table)
Water continues to sink until it reaches an impermeable layer.
The water table is the top of the area that is saturated with water.
Aquifer: An underground layer of permeable rock or sediment that contains water .
Ground water is stored here.
Located over or beside impermeable rock .
The water is constantly replenished.
Aquifers filter and clean water.
Provide fresh water source.
Underground water can be brought to the surface.
People collect water from wells and springs.
Spring: where the surface of the land dips below the water table and water bubbles up from underground.
Technology is helpful in dry and remote regions.
Well: a hole drilled into the ground to reach groundwater.
Continued See page 29.
Artesian Well: water flows to the surface naturally because of pressure exerted below the surface.
Hot Spring: a place where heated water reaches the surface.
Geyser: special kind of hot spring.
Underground water is heated and “plumbed” upward. Hot water and steam are pushed to the surface where they erupt.