Presentation on theme: "Science We need cotton balls Do Now: 3/12 Can you bring some?"— Presentation transcript:
1 Science We need cotton balls Do Now: 3/12 Can you bring some? HW: Read 16-1 and study for quiz1. Clear your table for the quizToday~ TTK 16:1 quiz and check~ Complete PPT w/notes: Water in the Air
2 The Water CycleThe transfer of water between the atmosphere and Earth’s surface.Water evaporates from plants and bodies of waterWater condenses in the atmosphere and forms cloudsClouds become saturated and water falls as precipitation to the surfaceWater runs off surface into lakes, streams and oceans.
3 What is Humidity? The amount of water vapor in the air. As water evaporates it becomes water vapor.Water vapor is invisible.Warm air canhold morewater vapor
4 What is Relative Humidity? Amount of water vapor in the air compared to the amount of water the air can hold.A percentage %Air holds all the water vapor it can= Saturated = 100% RH
5 Figuring Relative Humidity _actual water vapor content (g/m³)__ X 100 = RHsaturation water vapor content(g/m³)1 m³ of air at 10ºC has 5g of water vaporbut, at this temperature it can hold 8gCalculate RH g X 100 = 63%8 gAir holds 13g but can hold 25g13 g X 100 = 52%25 g
6 Factors Affecting Relative Humidity The amount of water vaporThe temperatureIf the water vapor stays the same:Temperature goes down RH% upTemperature goes up RH% down
7 How does that work??? Temperature ºC Saturated g 15 10 20 25 At 20 ºC with 15g of water vapor RH = 100%Temperature goes up to 25 ºC air could hold 20gSo…15g (what it has) X 100 = 75%20g (what it could have)
8 Measuring Relative Humidity 1. Measured with a psychrometer2. Has two thermometers* 1 wet bulb* 1 dry bulbUse the dry bulb temp and the chart
9 Determining Relative Humidity Use your book; page 484Determine the relative humidity for the following daysDayDryºCWetºCDifferºCRH %Mon1618Tue20Wed21
11 Condensation 1. Water vapor becomes a liquid 2. Happens when air is saturated3. Air cools to 100% relative humidity
12 Dew PointTemperature at which the air is saturated & condensation occursWhere does the water on the outside of a glasscome from???The cold liquid in the glass cools the air outside of the glassAir next to the glass reaches its Dew PointWater vapor in the air condenses on the glass!Quick Lab: pg 485What is the dew point temperature in the classroom today?
13 Clouds A collection on millions of tiny water droplets or ice crystals Warm air rises cools to dew pointwater vapor condenses to a liquid/solidAltitude and form/shape
14 Forms of Clouds Cumulus: Fluffy white with flat bottoms Stratus: Form in layers, cover largeareas of skyCirrus: Thin, feathery form at highaltitudes
15 Altitude of Clouds Cirro – forms at high altitude made of ice crystals Alto – middle altitudesmade of ice crystals & water dropletsLow altitudes have no special prefix