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

Remember… Wet spot felt cold Energy transfers from hand to water by conduction Because of the energy transfer, our skin felt cooler. The powerpoint follows the Teacher Guide starting with slide 12. Slides 2-11 are excellent slides leading into slide 12. Increased energy  water molecules move faster Faster moving molecules evaporated

Big Question What happens to the temperature of a gas when it is squeezed into a smaller volume?

When water is changed from a gas to a liquid Condensation When water is changed from a gas to a liquid

Heat Transfer & Condensation Is heat transfer involved? Yes Water Vapor Very Cold Surface Energy Reduces kinetic energy in water molecules Condenses into liquid water

Water Vapor Water Vapor Transfer energy to surroundings Vapor condenses Forms liquid water Water Vapor Energy Very Cold Surface Energy transfers to cold surface Drops of liquid water form there

Dew Condensation on a cold glass Dew is droplets of water seen on plants and other surfaces, usually in the morning

Dew forms? How does dew form? Surfaces cool Water vapor condense into droplets Cool leaves Water Vapor Energy

Dew Point The temperature at which air is saturated, causing water vapor to change from a gas to a liquid Cool leaves Water Vapor Energy

Dew Point Not the same everywhere Need to calculate the dew point for a particular location

Depends on… The amount of water vapor in the air Lots of water vapor = high dew point (higher temperature) Little water vapor = low dew point (lower temperature)

Pressure / Temperature Demonstration What happens to the temperature of a gas if you squeeze it into a smaller volume? Record observations on lab 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 With partners/group, discuss and respond to questions 2-4 on lab worksheet. Will review in 5 minutes. 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 Think: Have you seen any clouds lately? Think: What did they look like? Think: Where are clouds? Think: Are they always in the same place? Think and discuss: What is a cloud? Think and discuss: What is it made of? Think and discuss: Where do clouds come from? LOL: How do clouds form? TG- P. 211

Cloud in a Bottle Watch cloud in a bottle video with Mr. Yorke. TG- P. 211

Condensation Nuclei Flip ?s 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

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

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

Raindrops and Cloud Droplets Scientists have measure the average diameter (pg. 80) Precipitation is one of the most important factors that meteorologists monitor. Measure rain in rain gauge. Snow is melted and weighed to report inches or centimeters. TG- P. 213 Student Resource Book P. 80

Summary Five minutes on the timer Write everything you know or have learned about condensation.

Reading Two pages of notes on “Observing Clouds” Notes are free style, but must demonstrate organization Must include a blurb regarding Luke Howard Respond to Think Questions thoroughly, cleverly, and scientifically Notes be spread over 2 pages (no squishy)