Download Clouds and Water Cycle for wiki

Clouds…
and what
they tell us.
13.11
Fog
• Fog is actually a cloud that forms
near the ground.
• Fog is produced on clear nights when
energy from the surface radiates
upward but is not reflected back to
the Earth by any clouds.
• Thus, the air near the ground cools,
allowing water vapour to condense into
fog.
Clouds (p. 530)
• A cloud is a large collection of tiny water
droplets. (100 times smaller than the
average rain drop – Fig 2)
• Clouds are formed when warm air rises and
then cools at higher temperatures
• This cooling causes the water vapour to
condense in tiny water droplets.
• As many water droplets collect together,
they can make a rain drop.
• When the rain drop is large enough, gravity
causes it to fall to the Earth.
3 Ways Clouds are Made:
1. Convective Clouds:
- formed when warm air rises to high altitudes
where the water vapour then cools and condenses
forming tiny water droplets.
2. Frontal Clouds: (Fig. 3 p.531)
- formed when the leading or front edge of a
large air mass meets another air mass of
different temperature. The colder air mass
pushes the warmer up where it condenses forming
tiny water droplets.
3. Orographic Clouds: (Fig. 4)
- When objects, such as mountains,
force air to go up. When the air hits
the cooler air at higher altitudes,
condensation occurs.
Cloud Shapes
The two main cloud shapes are:
Cumulus – a billowing, rounded shape
Stratus – a flattened, layered shape
Cumulus Clouds
 Look like big cotton balls in the sky.
 Have very large spaces of clear sky between
them.
 Usually indicate unstable conditions
 Normally they don't carry any rain, but can
change into cumulonimbus (thunder) clouds.
Stratus Clouds
• Flattened layered shape
• Tend to grow horizontally
• Indicate stable conditions
Descriptive words
Cirrus Clouds are:
 Thin and wispy
 Found very high in the sky
 Point in the direction the wind is blowing
 No precipitation falls from cirrus clouds
 A sign of fair weather
Descriptive words…
Nimbus – means “produces rain”
Alto – means “mid-level” (just like as in
music)
Questions
1. What is “fog”?
2. Describe 3 ways in which clouds are produced.
3. List at least 3 characteristics for both
cumulus and stratus clouds.
4. What is the meaning of the prefixes: nimbus,
alto, and cirrus.
5. Use your answers from question 3-4 to :
a) describe a cumulonimbus clouds.
b) create a name for a high level cloud that
has a rounded shape and grows vertically.
6. Label BLM 13.11b on p. 532
Classification of Clouds
BLM 13.11
The Water Cycle
Chapter 13.8
The Hydrosphere
All of the Earth’s water, both fresh and salt,
forms what is called the hydrosphere.
• Only a small portion of the hydrosphere is
fresh water (2.5%) and of this
the majority is frozen in glaciers and polar
ice caps, and the rest is mainly
underground, or surface water (lakes,
rivers, etc.)
The Hydrosphere
• 97.5% is salt water
• Canada is one of the luckiest countries in
the world b/c our population is just .5% of
the world total, yet we have almost 10% of
the world’s supply of fresh water.
• B/C so much of the Earth’s surface is
water, our weather systems depend
greatly on it.
WATER CYCLE
Water on Earth is always changing. Its repeating
changes make a cycle. As water goes through
its cycle, it can be a solid (ice), a liquid (water),
or a gas (water vapour).
How do these changes happen?
Terms to know
• Evaporation
– the change of state from liquid to gas
– This is the purest naturally occurring water
• Condensation
– The change of state from water vapor to liquid
– Forming cloud stage
• Precipitation
– Water that falls to the ground
– Example: rain, snow, sleet, hail
• Runoff
– The water that flows over the ground surface
• Percolation
– The water that soaks into the ground forming pockets of groundwater. The
downward movement of water through soil and rock
• Sublimation
– Transition from solid to gas (no liquid phase)
• Transpiration
– The loss of water vapor through the leaves of plants into the atmosphere
Hydrologic Cycle = Water Cycle
WATER CYCLE
Adding or subtracting heat makes the cycle
work.
If heat is added to ice, it melts. If heat is added
to water, it evaporates.
Evaporation occurs when liquid water turns
into a gas called water vapour.
If heat is taken away from water vapour, it
condenses.
WATER CYCLE
If heat is taken away from water
vapour, it condenses.
Condensation occurs when water
vapour turns into a liquid.
If heat is taken away from liquid
water, it freezes to become ice.
WATER CYCLE
Ice changing directly to vapour
(skipping the liquid stage), is
called sublimation.
Transpiration occurs when water
evaporates from plants.
The water cycle is also known as the
hydrologic cycle.