Humidity. Reid Pierce Fulbright Jr. High Bentonville, AR

Transcription

1 Humidity Reid Pierce Fulbright Jr. High Bentonville, AR

2 Humidity After water evaporates, where does it go? to the air Describe a humid day Humidity how much water vapor is in the air

3 Warm air can hold more water vapor than cold air! Humidity Warm Air Cold Air

4 Humidity Relative humidity - the amount of water vapor in the air compared to what the air can "hold" at that temperature (measured as a %)

5 Humidity Psychrometer instrument used to measure relative humidity

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9 Humidity What happens when air that is full of water vapor (100% relative humidity) cools down? Remember that cooler air can t hold as much water vapor as warm air... it is now cold air and can t hold as much water vapor, the air will then be more than full and the water vapor will condense!

10 Two things are needed for water to condense (form clouds): 1. The water to cool to the dew point 2. Something to condense onto particles in the air (dust, smoke, salt crystals), the ground, etc Dew Point the temperature at which condensation begins the point at which dew will form Humidity

11 Two things are needed for water to condense: 1. The water to cool to the dew point 2. Something to condense onto particles in the air (dust, smoke, salt crystals), the ground, etc What ifs What if that something is the ground? What if the temperature of the ground is below freezing? What if that something is dust, high in the sky? Humidity

12 Dew Point Calculator

13 Cloud Formation Water vapor condenses on tiny particles in the air, forming a cloud. Warm, moist air rises from the surface. As it rises, it cools. At a certain height, air cools to the dew point and condensation begins.

14 Upper Troposphere is Cold Warmer, Moist, Less Dense Air Rises Low Pressure Colder, Dry, More Dense Air Sinks High Pressure Ground is heated by radiation

15 Warm air that holds a lot of water vapor rises Why do clouds form? As it rises it cools and condenses onto a particle This forms tiny water droplets

16 There are 3 main types of clouds. 1. Cirrus clouds are curly or feathery, highest clouds * they indicate a front is on the way

17 There are 3 main types of clouds. 2. Cumulus clouds are puffy and piled up, middle height clouds * short cumulus clouds indicate fair skies (fair weather), tall cumulus clouds indicate thunderstorms

18 There are 3 main types of clouds. 3. Stratus clouds are flat and/or layered, lowest clouds * they may indicate precipitation = drizzle, rain or snow

19 Another common type of cloud: Cumulonimbus is a high towering cloud that can produce a thunderstorm.

20 Try to pick out the types indicated in this photo. cumulus cirrus

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22 What type of clouds are these? What type of weather do they indicate?

23 What type of clouds are these? What kind of weather does this type indicate?

24 What type of clouds are these? What kind of weather does this type indicate?

25 Humidity Predict: What if the particle just came out of a smoke stack or the exhaust of a car?

26 Acid Rain precipitation with an acidic ph formed when water vapor condenses on pollution in the air Carbonic acid is produced when carbon dioxide gas from car exhaust dissolves in rain drops Nitrous acid is produced when nitrogen dioxide gas from car exhaust dissolves in rain Sulfurous acid is produced when sulfur from coal burning power plants dissolves in rain

27 Conifers appear to be particularly affected, with needles dropping off, and seedlings failing to produce new trees.

28 Many toxic metals are held in the ground in compounds. Acid rain can break down these compounds, freeing the metals and washing them into water sources such as rivers. Can t eat fish contaminated with mercury.

29 Before Acid Rain After Acid Rain A less serious problem is the damage acid rain causes to certain materials, particularly limestone and marble.

30 Cause Turns surface runoff more acidic Turns forest soil more acidic Speeds decay of building materials & statues Effect harmful to plants & animals damages plants, kills forests loss of buildings &cultural artifacts