Transcript Water Cycle - ahbsciencereview

The Water Cycle
Facts About Water
• Water is the most important material on
earth.
• Water continuously changes forms so it can be
used and recycled.
• Matter on earth, including water, is never
created or destroyed.
• Approximately 70% of the planet is covered in
water.
Forms of Water
• Water can be found in three forms
– Liquid
• Example: oceans, lakes, rivers, streams, groundwater
– Gas
• Example: water vapor
– Solid
• Example: ice, snow
The Water Cycle
•Precipitation
•Runoff
•Evaporation
•Condensation
Precipitation
• Precipitation occurs when droplets in clouds
join together and become large enough.
• Precipitation can fall in the form of rain, snow,
sleet, or hail, depending on the temperature
of the air through which the droplets fall.
Runoff
• After precipitation occurs water moves
through the environment back towards larger
bodies of water.
http://www.desktopscenes.com/Scenes%20from%20Glacier%20National%20Park%20(2004)/Runoff%20
Waterfall%20Near%20Logan%20Pass.jpg
Evaporation
• Evaporation happens at all times.
• The rate of evaporation increases when
temperatures are higher and air surrounding
a water source is drier.
• Living things also contribute through
perspiration, which is the release of water
vapor through the skin.
• We can also exhale water vapor in our
breath.
Condensation
• The air can hold only a limited amount of water
vapor.
• The amount of water vapor the air can hold depends
on the temperature of the air.
– Warm air can hold more water vapor than cold air.
• When air reaches a temperature where it can hold no
more water vapor it is said to be saturated. This is
called the dew point.
• When the temperature falls below the dew point the
water vapor begins to condense, or come together.
• High above the ground clouds form. Near the ground
fog forms.
• On solid ground dew or frost forms depending on the
temperature.
Condensation
• When most air cools, water vapor condenses
and clings to tiny particles of dust, smoke and
salt, forming clouds.
• When the droplets in clouds join together
and become large enough, they fall to the
ground as precipitation.
Pictures
• All pictures are from Microsoft Clipart.