450 likes | 462 Views
Learn about weather phenomena, tools, and atmospheric relationships in an engaging way. Explore cloud formation, air movements, temperature, and humidity. Discover the science behind dew, wind, and global atmospheric patterns.
E N D
Today – Friday, 1/20/12 • Attendance • Calendar • Review Weather • Lab # 26 Isoline Review
Weather Hey, is this cool or what?
Seasons occur because 1) the Earth is tilted 2) the Earth revolves around the sun.
Aneroid Barometers – measure air pressure by measuring how much air is pushing in on the can.
Mercury Barometers – measure the force of air pressing on liquid mercury.
C. Water Vapor – water in the form of a gas. • mini movie on phases of water - brain pop
Humidity – the amount of water vapor in the air. • humidity brainpop
Dew – drops of water that form on substances when the air gets too cold to hold water vapor.
D. Air Movements • Why does air circulate (move) around in the atmosphere?
D. Air Movements • Less dense (warmer) air rises • More dense (cooler) air sinks
D. Air Movements • Some Definitions: • Air currents: are vertical movements of air • Wind: horizontal movement of air • Described in both direction and speed • Named for the direction from which it blows
D. Air Movements • Wind Vane – is a pointer that shows direction • Anemometer – an instrument that measures wind speed.
E. Atmospheric Transparency • All the gases in our atmosphere are transparent (see through). • There are many substances that become suspended in the atmosphere that are not transparent (dust, ash, smoke, salt, droplets of liquid called aerosols)
E. Atmospheric Transparency • Visibility is the horizontal distance through which the eye can distinguish objects in miles.
III. Weather Stations • Know how to read weather stations. • Cloud cover is the fraction of the sky that is blocked by the clouds.
IV. Relationships • A. Air Temperature and Pressure • As temperature increases, the pressure decreases • When the temperature increases, the molecules move faster, spread out and become less dense. • As temperature decreases, the air pressure increases. • Colder, slower, closer, more dense, more pressure
IV. Relationships • A. Air temperature and pressure • As P increases, T increases • Move closer, more friction, more heat • As P decreases, T decreases • Move away, less friction, less heat
IV. Relationships • B. Air pressure and humidity • Water Vapor is much lighter than the other gases in the atmosphere. • So if the amount of water vapor increases, the other heavier molecules are pushed out. • The higher the humidity, the ___ the air pressure. • The lower the humidity, the ___ the air pressure.
IV. Relationships • C. Air Temperature and humidity • If the temperature increases, the relative humidity will decrease. • Warmer air has the capacity to hold more, % decreases • If the temperature decreases, the relative humidity increases. • Cooler air has holds less water vapor, % increases.
IV. Relationships • D. Air pressure and wind • Winds blow from regions of HIGH air pressure to regions of LOW air pressure. H L
IV. Relationships • Winds curve to the right in the Northern Hemisphere because of the Coriolis Effect. • (Curve to the left in the Southern Hemisphere) L H
IV. Relationships • E. Global Winds/Planetary Winds
E. Cloud Formation • Clouds and precipitation are formed when air is cooled below its dew point and water vapor condenses into tiny water droplets or ice crystals. • Condensation means changing phases from a gas to a liquid. • Precipitation removes dust/dirt and many pollutants from the atmosphere. Ask me what Condensation Nuclei means!
E. Cloud Formation • Sublimation is the change of phase from a gas directly to a solid • Fog is a cloud whose base is at ground level. It forms when moist air at the ground level is cooled below its dew point.
More on Clouds • brainpop clouds