Condensation, Clouds, Precipitation Investigation 6 Water in the Air Condensation, Clouds, Precipitation Investigation 6 TG- P.206-208

Pressure / Temperature Demonstration What happens to the temperature of a gas if you squeeze it into a smaller volume? Pressure/Temperature Demonstration worksheet TG- P. 209 Student Lab Notebook- P.37 Teacher Answer Master- P.400

Soda Bottle Demo #1 Resting temperature Apply pressure to the bottle and hold it Observe the temperature Release the pressure and observe the temperature TG- P. 209 Student Lab Notebook- P.37 Teacher Answer Master- P.400

Soda Bottle Demo #2 Starting temperature Pump the cap 40 times or more as you watch the temperature Observe the pressure Release the pressure and observe the temperature TG- P. 209 Student Lab Notebook- P.37 Teacher Answer Master- P.400

Results  (added air molecules)   Squeezed by Hand Bottle Soda-bottle Pump Bottle Volume   (added air molecules) Pressure  Temperature TG- P. 209 Student Lab Notebook- P.37 Teacher Answer Master- P.400

What happened… When we released the pressure Temperature decreased TG- P. 210 Student Lab Notebook- P.37 Teacher Answer Master- P.400

Questions Answer questions 2, 3 and 4 on the Pressure/Temperature Demonstration worksheet TG- P. 210 Student Lab Notebook- P.37 Teacher Answer Master- P.400

Question 2 Answer V  = MM  = P  = T  Decreasing the volume causes the molecules to move faster with the greater pressure, increasing the temperature V  = MM  = P  = T  TG- P. 210 Student Lab Notebook- P.37 Teacher Answer Master- P.400

Question 3 Answer V  = MM  = P  = T  Squeezed the sides of the bottle = decreased the space = pushed down on the plunger. The number of air molecules stayed the same in a smaller space = increase pressure, increased temperature TG- P. 210 Student Lab Notebook- P.37 Teacher Answer Master- P.400 V  = MM  = P  = T 

Question 4 Answer V  = MM  = P  = T  Temperature must go up in the syringe because the pressure goes up V  = MM  = P  = T  TG- P. 210 Student Lab Notebook- P.37 Teacher Answer Master- P.400

Summarize Gas molecules are forced closer Force smaller volume More collision occur Increase in temperature and pressure Force smaller volume TG- P. 210 Student Lab Notebook- P.37 Teacher Answer Master- P.400

Summarize Gas molecules spread out Less collision occur Decrease in temperature and pressure Increase the volume

Cloud Formation Have you seen any clouds lately? What did they look like? Where are clouds? Are they always in the same place? What is a cloud? What is it made of? Where do clouds come from? How do you think they form? TG- P. 211

2 Types of Clouds Clouds appear as one of these 2 basic types… Stratiform– clouds that are flat and layered. These form when weather is stable. They are the result of a large, moist air mass being lifted. Cumuliform—puffy, fast-moving, and rapidly growing clouds.

Clouds are classified by height

Cloud Word Orgins Cumulus- Latin – “heap” Stratus – Latin – “layer” Nimbus – Latin – “rain-bearing” Cirro- “high” Alto- “middle”

High Cirrus Cirrocumulus Cirrostratus Clouds forming above 5000 meters have cirro- prefix and since the temperatures are so cold at such high elevations, these clouds are primarily composed of ice crystals. These clouds are thin and wispy, blown by high winds into long streamers. They are typically thin and white in appearance, but can appear in a magnificent array of colors when the sun is low on the horizon. Cirrus Cirrocumulus Cirrostratus

Middle Clouds that form between 2000-5000 m are given names that begin with the alto- prefix. Nimbostratus Altostratus Altocumulus

Low Low level clouds form below 2000 meters. (no special prefix) -Stratus -Stratocumulus -Cumulus -Cumulonimbus

Cloud in a Bottle? Using a 2-liter soda bottle, containing 25 mL of water Water vapor into the air? Shaking the bottle Warming the water TG- P. 211

Shake, shake, shake Have we formed a cloud yet? NOT YET TG- P. 211

Cloud recipe Saturate the air with water vapor Then Shake the bottle Warm the bottle by holding it in your hands Increase the pressure to increase the temperature Then Release the pressure on the bottom to decrease the temperature (to get the water vapor to condense - dew point) TG- P. 212

Did it Work? NOT YET! There is a piece missing There is nothing for the water droplets to form on!! TG- P. 212

What’s Happening? When you let it expand the water condenses on the smoke particles forming a cloud. When the bottle is compressed the air gets hotter so the water evaporates. You start off with some  water in the bottle and some smoke.

Condensation Nucleus Clouds are composed of tiny droplets of condense liquid water Water vapor is condensing on the particles of smoke and the plastic of the bottle The particle on which water vapor condenses in the air to form a cloud TG- P. 212

Is This How Real Clouds Form? The process is very similar to how clouds from on a sunny day. Warm moist air rises, and as it rises there is less air above it so the pressure reduces.

In Real Clouds What would be the condensation nuclei in the outside air? Dust Smog Air pollution Smoke Salt Chemicals TG- P. 212

How do Clouds Form?

Precipitation Water that falls from the sky Kinds of precipitation Rain Snow Sleet Hail TG- P. 213

Raindrops and Cloud Droplets Measure the average diameters Comparison of size - page 80 in the Resource Book TG- P. 213 Student Resource Book P. 80

Measuring Precipitation Most important weather factors monitored Measured with a rain gauge TG- P. 213 Student Resource Book P. 80

Fog Forming on Land

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