Transcript water in the atmosphere - Grosse Pointe Public School System

WATER IN THE
ATMOSPHERE
Honors Earth science
Chapter 16
Water vapor
• Is a gas
• You cannot see it!!!
• What state of matter are:
– Clouds?
– Fog?
Give examples of water in the
atmosphere
• Solids-
• Liquids-
• Gas-
Water changes state
(from worksheet)
• Liquid → Solid
– freezing
• Solid → liquid
– melting
• Gas (water vapor)→ liquid
condensation
• Liquid → gas
– evaporation
Water changes state
• Gas to solid?
Deposition
– Frost
– Solid to gas?
– Sublimation
• Dry ice
– Most water vapor enters atmosphere through
– EVAPORATION
WORKSHEET
LATENT HEAT
• la·tent heat- nounPHYSICS
• the heat required to convert a solid into a liquid
or vapor, or a liquid into a vapor, without change
of temperature.
• Energy (heat) that is used during a phase
change
http://jamaica.
u.arizona.edu/
ic/nats1011/le
ctures/ch05/FI
G05_006.JPG
Relative Humidity
Capacity of Air is dependent on
temperature
• Warm air can hold more water vapor than
cold air!!
relative humidity
• Temp.= 31ºC water vapor in air= 25 g
• Calculate the rh:
25/29.4= .85 x 100= 85%
85% of the air is filled with water vapor
What happens at 100% RH?
condensation!
Relative humidity
use real data
• Air temp=
• Relative humidity is
• What is the water vapor content?
How do we measure water vapor
content?
• Cool it until it can’t hold anymore moisture.
• This temp is DEW POINT
• Then use chart
Dew point
• Temperature at which
100% humidity occurs
• (condensation temp)
• Frost will form if DP is
below freezing
– Gas
solid
Who cares about dew point?
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Lawn care
Sports on grass
Farmers/ Gardeners
Bad hair days?
Tell the humidity
– When air temp. is closer to dew point temp,
humidity is higher
Today’s weather
Grosse Pointe