1. Aim: How do clouds form in the troposphere?

2. Russell the Boy Scout, describes the characteristics about cumulonimbus clouds but is ignored. How would you describe the characteristics' of this cloud.

3. How do we define cloud? Cloud – a collection of millions of tiny water droplets and/or ice crystals suspended in the atmosphere by condensation How does condensation occur in the atmosphere? Condensation nuclei – particles of dust or salt upon which liquid water droplet condense on the surface How much energy is released during condensation?

4. How can we make our own cloud? Clouds form when warm moist air rises, expands and cools due to low pressure. The water vapor temperature cools down to the dewpoint temperature. Particles in the air provide a surface for the water vapor to condense on and a cloud is formed.

5. How do clouds form in the atmosphere? Cloud Formation 1.Warm moist air rises, expands and cools 2.Air temperature cools to dewpoint temperature (equal) 3.Condensation occurs only when condensation nuclei are present and cloud forms 4.Precipitation - occurs when water droplets are large/heavy enough to fall 5.Precipitation cleans the atmosphere by taking dust and other particles (aerosols) out of the air (pollution)

6. Types of clouds Cirrus – high wispy clouds (fair weather) Stratus – Middle horizontally layered cloud Cumulus – low fluffy clouds with flat bottoms Nimbus = rain Ex. cumulonimbus (thundercloud), nimbostratus (rain cloud) Fog – cloud resting on earths surface How would you describe the different types of clouds in our atmosphere?

7. Summary Activity 1. The incomplete flowchart below shows some of the changes that occur in warm air as it rises to form a cloud. Which statement should be placed in the empty box to accurately complete the flowchart? (1)The air warms as it expands(3) The air’s relative humidity decreases to zero (2)The air cools until it reaches the dewpoint(4) The air enters the thermosphere

8. Extra Questions

9. What are some types of precipitation? Temperatures above 0ºC = Temperatures below 0ºC = rain snow/ice

15. How do we define cloud? Cloud – a collection of millions of tiny suspended in the atmosphere by condensation How does condensation occur in the atmosphere? – particles of dust or salt upon which liquid water droplet on the surface How much energy is released during condensation?

16. How do clouds form in the atmosphere? Cloud Formation 1.Warm moist air 2.Air temperature cools to (equal) 3.Condensation occurs only when are present and cloud forms 4. - occurs when water droplets are large/heavy enough to fall 5.Precipitation cleans the atmosphere by taking dust and other particles (aerosols) out of the air (pollution) Types of clouds Cirrus – (fair weather) Stratus –horizontally layered cloud Cumulus – with flat bottoms Nimbus = Ex. cumulonimbus (thundercloud), nimbostratus (rain cloud) Fog – cloud resting on earths surface