Dew Point and Weather

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Dew Point and Weather
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Measuring the Dew Point Temperature
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A review and two questions to think about

• What are the states of matter?
• Can we see water in all its states?
• 1 What connection might there be to weather?
• 2 Where was the water just before it formed the
  dew we see?

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A Day with Rain
Rain
Air Temperature
A Day without Rain
Dew Point Temperature
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Air Temp. Dew Pt. Temp
Hurricane Irene 2011 (NYC)
Wind Speed Direction From
48 hours ?
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Some How-Tos

• In lab notebook put date and
• ____ Air Temp Inside
• ____ Air Temp Outside
• ____ Water Temperature Before Ice
• ____ Dew Point Temperature
• If you have time, see what the coldest
  temperature you can get to is.

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We Need a Way to Represent Our Class Results
Values for Air temp (then water Temp, then Dew
point)
?

• Put values on board
• So we can compare results from the other classes,
  we need to come up with ONE number for each
  measurement that represents our class results
• ___ Class Air Temp. ____Class Water Temp.
• ____ Class Dew Point Temp.
• How can we do this?

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One possible approach
Air Temp.
lt -- put in order --gt
Tape or use magnets to hold results to board,
sort, then decide on a number
Water Temp.
Dew Point Temp.
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The Day Before Mondays Temperature and Dew
Point Temperature
Why might Dr. Stroup have been nervous about our
ability to use liquid water (whats in the cup)
to measure dew point. (What happens at 0 C?
so to find dew on the side of the cup the water
in the cup would need to be ._____?
0 C
Negative C What state would the water in the
cup have to be in to measure these dew point
temperatures?
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Teacher (Class) Approx. Time Time in 24 hours Class Air Temp. Class Dew Point Temp.





Our Data
Graph for Tuesday
Plot Class Results
Sept. 13, 2011
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If farther apart, then evaporation is faster.
If all summer the graphs have been far apart
and weve had no rain, what does this mean for
how dry the plants and trees are? What would
this mean if a fire got started?
Rain
Tuesday
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http//austin.ynn.com/
http//austin.ynn.com/content/top_stories/280357/d
ay-5--1--386-homes-destroyed-in-bastrop?ap1MP4
video
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Where was the water just before it formed the dew
on the side of the cup?
From the water? From the air? How might putting
food coloring in the water help us figure this
out?
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Cloud in a Bottle Activity Where was the water
just before it formed into dew or the cloud in
the bottle? Does it jump up or is it in the
air?
(show movie after cloud in bottle)
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Water Cycle
Water on earth moves in a continuous cycle. This
is called THE WATER CYCLE. There is about the
same amount of water on earth now that there was
when the dinosaurs roamed our planet http//www-k
12.atmos.washington.edu/k12/pilot/water_cycle/grab
ber2.html
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End
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Web Calculators
Type in Air Temp. And Dew Point Then Press
Calculate

• http//www.esa.act.gov.au/firebreak/humidity.html

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http//weather.yahoo.com/forecast/USTX0057.html
6/23/06
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More information at

• http//www.usatoday.com/weather/whumdef.htm