Transcript water in the Atmosphere

Bobbling along in the sky , hot air balloons look like a
fun way to spend a day. Before the invention of
satellites or airplanes though, hot air balloons were
used by scientists to study the atmosphere. Riding in
their balloons, scientists gathered information about
temperatures, humidity and even cosmic rays. For
more than 150 years, balloons were considered
cutting-edge atmospheric observatories.
What are some differences between
research hot air balloons of the past and
the scientific balloons we use today?
Text Reference 56-63
1. Water makes up 75% of the surface of
the earth
2. Water exists in three forms or phases
(yup! Write it all!)
Freezing
Solid - Ice
Melting
Liquid - Water
Condensing
Gas - Vapor
Evaporating
3. Phase Changes of Water
a. Evaporation-Water molecules heat
up and gain energy. They begin to
move faster and change from the
liquid to gas phase
Water molecules as a
liquid
Water molecules as a
vapor
A typical glass of water
3b. Condensation
Water molecules slow down and lose
energy changing from a gas to a liquid
phase collecting on grass and objects in
the form of dew. If the temperature
falls below 0o C , it becomes frost.
Dew Point - the temperature at
which water vapor condenses
3c. Transpiration
Water transferred from plants to the
atmosphere as water vapor as they take
in CO2
4. The Water Cycle
1. Heat energy from the
sun warms surface water on
the earth, causing it to
evaporate and transpirate
3. Precipitation
(rain, snow, hail)
returns water to the
soil
2. Water vapor
from condenses
into clouds
4. Deep ground water and runoff
return water to the rivers, lakes,
and oceans
5. Humidity
A measure of the amount of water vapor in
the air
• Warm air holds more moisture than cool air
• Air feels cooler when the humidity is lower, the air is
more capable of evaporating water from sweat
• Measured with an instrument called a “Psychrometer”
Wet Bulb
Dry Bulb
• Saturation-the point at which evaporation and
condensation are equal (warmer-higher; cold-lower)
6. Relative Humidity
The percentage of water vapor in the
air compared to the maximum amount
the air could hold. For example:
• If the air can hold 8 grams of water, and it
has 8 grams in it, the relative humidity would
be 100%
• If the air can hold 8 grams of water, and it
has 4 grams in it, the relative humidity would
be 50%
7. Dew Point
• The
temperature at
which
condensation
begins
a. Clouds form when the temperature
falls below the dew point
b. Small particles of dust must be
present for the water to condense
c. Three Basic Types:
 Cumulus
 Stratus
 Cirrus
C1-Cumulus (“heap”)
Clouds
Thick and puffy, cotton
candy clouds associated
with fair weather
C2-Cumulonimbus clouds are vertically
developed clouds that can yield
lightning, hail, and heavy rainfall.
C3-Stratus (“spread out”) Clouds
Low level layer of clouds that often
covers the entire sky.
C4-Nimbostratus clouds are heavier
stratus clouds that give long periods
of steady rain or snow.
C5-Cirrus - Wispy, feather
clouds
◦ Only form at high levels
◦ Made mostly of ice crystals
◦ Name means “curl of hair”
Fog is a low-lying cloud at or near
the surface of the earth
Common Types:
• Rain-bigger than 0.5 mm
•Drizzle-less than 0.5 mm
• Freezing Rain- When rain strikes a
cold surface and turns to ice
•Sleet-When rain falls through
freezing air and turns to ice
Snow - Ice crystals formed inside a cloud,
form in the presence of little wind
Hail - Pellets of ice greater than 5 mm in
diameter. Form exclusively inside
cumulonimbus clouds and are associated
with storms
Hail forms in cumulonimbus clouds.
The End