Science We need cotton balls Do Now: 3/12 Can you bring some? Science We need cotton balls Do Now:...
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Transcript of Science We need cotton balls Do Now: 3/12 Can you bring some? Science We need cotton balls Do Now:...
Science We need cotton balls Science We need cotton balls Do Now: 3/12 Can you bring some?Do Now: 3/12 Can you bring some?
HW: Read 16-1 and study for quizHW: Read 16-1 and study for quiz
1. Clear your table for the quiz 1. Clear your table for the quiz TodayToday ~ TTK 16:1 quiz and check~ TTK 16:1 quiz and check ~ Complete PPT w/notes: Water in the Air~ Complete PPT w/notes: Water in the Air
The Water CycleThe Water CycleThe transfer of water between the atmosphere and Earth’s surface.
1. Water evaporates from plants and bodies of water
2. Water condenses in the atmosphere and forms clouds
3. Clouds become saturated and water falls as precipitation to the surface
4. Water runs off surface into lakes, streams and oceans.
What is Humidity?What is Humidity?
1.1. The amount of water vapor in the air.The amount of water vapor in the air.
2.2. As water evaporates it becomes water As water evaporates it becomes water vapor.vapor.
3.3. Water vapor is invisible.Water vapor is invisible.
4.4. Warm air can Warm air can
hold more hold more
water vaporwater vapor
What is Relative Humidity?What is Relative Humidity?
1.1. Amount of water vapor in the air Amount of water vapor in the air compared to the amount of water the compared to the amount of water the air can hold. air can hold.
2.2. A percentage % A percentage %
3.3. Air holds all the water vapor it can Air holds all the water vapor it can
= Saturated = 100% RH= Saturated = 100% RH
Figuring Relative HumidityFiguring Relative Humidity__actual water vapor content (g/mactual water vapor content (g/m³)__ ³)__ X 100 = RH X 100 = RHsaturation water vapor content(g/m³)saturation water vapor content(g/m³)
1 m³ of air at 10ºC has 5g of water vapor1 m³ of air at 10ºC has 5g of water vaporbut, at this temperature it can hold 8gbut, at this temperature it can hold 8g
Calculate RH Calculate RH 5 g 5 g X 100 = 63% X 100 = 63% 8 g8 g
Air holds 13g but can hold 25gAir holds 13g but can hold 25g
13 g13 g X 100 = 52% X 100 = 52% 25 g25 g
Factors Affecting Relative HumidityFactors Affecting Relative Humidity
1.1. The amount of water vaporThe amount of water vapor
2.2. The temperatureThe temperature
If the water vapor stays the same:If the water vapor stays the same:
Temperature goes down RH% Temperature goes down RH% up up
Temperature goes up RH% Temperature goes up RH% down down
How does that work???How does that work???
At 20 At 20 ºC with 15g of water vapor RH = 100%ºC with 15g of water vapor RH = 100%Temperature goes up to 25 ºC air could hold 20gTemperature goes up to 25 ºC air could hold 20gSo… So… 15g (what it has) 15g (what it has) X 100 = 75% X 100 = 75% 20g (what it could have)20g (what it could have)
Temperature Temperature ºCºC Saturated gSaturated g
1515 1010
2020 1515
2525 2020
Measuring Relative HumidityMeasuring Relative Humidity
1. Measured with a 1. Measured with a psychrometerpsychrometer
2. Has two 2. Has two thermometersthermometers
* 1 wet bulb* 1 wet bulb
* 1 dry bulb * 1 dry bulb
Use the dry bulb temp Use the dry bulb temp and the chartand the chart
Determining Relative HumidityDetermining Relative Humidity
Use your book; page 484Use your book; page 484
Determine the relative humidity for the Determine the relative humidity for the following daysfollowing days
Day Day DryDryºCºC WetWetºCºC DifferDifferººCC
RH %RH %
MonMon 1616 1818
TueTue 1616 2020
WedWed 1818 2121
Determining Relative HumidityDetermining Relative Humidity
Day Day DryDryºCºC WetWetºCºC DifferDifferºCºC
RH %RH %
MonMon 1616 1818 22 8181
TueTue 1616 2020 44 6363
WedWed 1818 2121 33 7373
CondensationCondensation
1. Water vapor becomes a liquid1. Water vapor becomes a liquid
2. Happens when air is saturated2. Happens when air is saturated
3. Air cools to 100% relative humidity3. Air cools to 100% relative humidity
Dew PointDew Point
Temperature at which the air is saturated & condensation occursTemperature at which the air is saturated & condensation occurs
Where does the water on the outside of a glass Where does the water on the outside of a glass come from???come from???
The cold liquid in the glass cools the air outside of the glassThe cold liquid in the glass cools the air outside of the glassAir next to the glass reaches its Dew PointAir next to the glass reaches its Dew Point
Water vapor in the air condenses on the glass!Water vapor in the air condenses on the glass!
Quick Lab: pg 485Quick Lab: pg 485
What is the dew point temperature in the classroom today?What is the dew point temperature in the classroom today?
CloudsClouds
A collection on millions of tiny water droplets A collection on millions of tiny water droplets or ice crystalsor ice crystals
Warm air rises Warm air rises cools to dew point cools to dew point
water vapor condenses to a liquid/solidwater vapor condenses to a liquid/solid
Altitude and form/shapeAltitude and form/shape
Forms of CloudsForms of Clouds
Cumulus:Cumulus: Fluffy white with Fluffy white with flat bottomsflat bottoms
Stratus:Stratus: Form in layers, cover large Form in layers, cover large areas of skyareas of sky
Cirrus:Cirrus: Thin, feathery form at high Thin, feathery form at high altitudesaltitudes
Altitude of CloudsAltitude of Clouds
Cirro – forms at high altitudeCirro – forms at high altitude
made of ice crystalsmade of ice crystals Alto – middle altitudesAlto – middle altitudes
made of ice crystals & water dropletsmade of ice crystals & water droplets Low altitudes have no special prefixLow altitudes have no special prefix