2. Weather How Cold Will it be Tomorrow?

3. Heat Transfer As temperature rises, the energy within a molecule also increases Radiation-direct transfer of heat energy by electromagnetic waves Conduction- direct transfer of heat from one substance to another that it is touching (metals) Convection-heat is transferred through a gas or liquid (causes heating of atmosphere)

4. Heat Transfer - Conduction & Convection

5. Heat Transfer - Radiation

6. Air Pressure Increase elevation = decreased air pressure –Air pressure drops 10 mm for every 125 m rise Increased water vapor = decreased air press. –Water molecules are lighter than other gases Increased temperature = decrease air press. –Increased temp= molecules spread out

7. Earth’s Atmosphere

8. Barometer Barometer is the instrument that is used to measure air pressure High Pressure system brings nice weather. Low Pressure system brings precipitation and change in weather.

9. Air Fronts A front is a boundary between 2 air masses Cold front- forward edge of a cold air mass Warm front - forward edge of a warm air mass Stationary front- air masses that do not move Occluded front- a warm air front is trapped between two cold fronts

10. Fronts

11. Precipitation Precipitation occurs when water condenses Types of precipitation –Rain, snow, sleet, hail, fog

12. Moisture - Water Cycle

13. Clouds Clouds form when water droplets and ice form around dust and other particles in air Types of Clouds- –Cumulus (big/puffy) –Stratus (flat, sheet-like) –Cirrus (light/feathery)

14. Clouds

15. Dew Point Dew Point is the temperature at which condensation takes place - air becomes saturated As air cools, it cannot hold as much water

16. Humidity Humidity- the amount of water vapor in the air High humidity = large amounts of water in air (low= small amt) Air can hold more water when it is warm because the particles are further apart Saturated: when the air is full and cannot hold anymore water

17. Lake Effect Snow LES - occurs when land near Lake Erie and Lake Ontario freezes faster than the lakes (warmer air over water, cooler air over land) Usually occurs within 40 km of lake

18. Weather Maps Meterologists use computers and satellites to predict weather patterns Map symbols include: –Warm/cold fronts- Air pressure (isobars) –Wind speed/direction- Cloud cover symbols

19. Weather Prediction