Dew Point and Weather

Measuring the Dew Point Temperature

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?

A Day with Rain

A Day without

Rain

Air Temperature

Dew Point Temperature

Rain

Hurricane Irene2011 (NYC)

WindSpeed & Direction From

Air Temp.& Dew Pt.Temp

48 hours

Some How-To’s

• 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.

We Need a Way to Represent Our Class Results

• 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?

?

Values forAir temp (then waterTemp, thenDew point)

Tape or use magnets to hold results to board, sort, then decide on a number

One possible approach …

< -- put in order -->Air Temp.

Water Temp.

Dew Point Temp.

The Day Before:Monday’s Temperature and Dew Point Temperature

Why might Dr. Stroup have been nervous about our ability to use liquid water (what’s 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 ˚ CWhat state would the water in the cup have to be into measure these dew point temperatures?

Our DataTeacher (Class)

Approx. Time

Time in 24 hours

Class Air Temp.

Class Dew Point Temp.

Plot ClassResults

Graph for Tuesday

Sept. 13, 2011

RainIf farther apart, then evaporation is faster.

If all summer the graphs have been far apart and we’ve had no rain, what does this mean for how dry the plants and trees are? What would this mean if a fire got started?

Tuesday

http://austin.ynn.com/

http://austin.ynn.com/content/top_stories/280357/day-5--1--386-homes-destroyed-in-bastrop?ap=1&MP4 video

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?

Cloud in a Bottle Activity

Where was the water just beforeit 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)

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-k12.atmos.washington.edu/k12/pilot/water_cycle/grabber2.html

Water Cycle

End

Web Calculators

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

Type in Air Temp.And Dew PointThen Press Calculate

http://weather.yahoo.com/forecast/USTX0057.html

6/23/06

More information at

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