Post on 19-Jan-2018
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WATER IN THE ATMOSPHERE
Honors Earth scienceChapter 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)→ liquidcondensation
• 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/lectures/ch05/FIG05_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 vaporWhat happens at 100% RH?condensation!
Relative humidityuse 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?
• 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
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