Today – Friday, 1/20/12

1. Today – Friday, 1/20/12 • Attendance • Calendar • Review Weather • Lab # 26 Isoline Review

2. Weather Hey, is this cool or what?

3. Weather – the short term condition of the atmosphere

5. Meteorologist – scientist who studies the weather

6. A. Temperature – the amount of heat energy

7. The angle of the sun influences the temperature.

8. It is colder at night where there are no clouds.

9. Rotation – spinning on an axis

10. Seasons occur because 1) the Earth is tilted 2) the Earth revolves around the sun.

11. Temperature is measured with a thermometer.

12. B. Air has weight that presses down on the earth.

13. Aneroid Barometers – measure air pressure by measuring how much air is pushing in on the can.

14. Mercury Barometers – measure the force of air pressing on liquid mercury.

15. Fair Weather – blue skies, less humid

16. Stormy Weather

17. High air pressure gradients make high winds.

18. C. Water Vapor – water in the form of a gas. • mini movie on phases of water - brain pop

19. Humidity – the amount of water vapor in the air. • humidity brainpop

20. Sling Psychrometer - used to measure relative humidity

21. Relative Humidity Chart

22. Dew – drops of water that form on substances when the air gets too cold to hold water vapor.

23. Dew Point Chart

24. D. Air Movements • Why does air circulate (move) around in the atmosphere?

25. D. Air Movements • Less dense (warmer) air rises • More dense (cooler) air sinks

26. 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

27. D. Air Movements • Wind Vane – is a pointer that shows direction • Anemometer – an instrument that measures wind speed.

28. 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)

29. E. Atmospheric Transparency • Visibility is the horizontal distance through which the eye can distinguish objects in miles.

30. III. Weather Stations • Know how to read weather stations. • Cloud cover is the fraction of the sky that is blocked by the clouds.

32. 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

33. 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

34. 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.

35. 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.

36. IV. Relationships • D. Air pressure and wind • Winds blow from regions of HIGH air pressure to regions of LOW air pressure. H L

37. 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

38. Draw this in on page 10.

39. Get it? SEA BREEZE

41. IV. Relationships • E. Global Winds/Planetary Winds

42. 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!

43. 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.

44. More on Clouds • brainpop clouds

45. The End of Unit 10.