Transcript Dew Point 1. - Leon County Schools

Describing Weather
(cont.)
Ms. Cervera
Bellringer # 2
Dew Point
1. When does dew form? Why?
2. What do you think dew point indicates?
Today’s Objectives & Practices
Students will be able to…
 Relate humidity to cloud formation
 Describe how humidity and relative humidity are related
 Explain how saturation relates to dew point
Constructing Explanations: Students will construct explanations that focus on
explaining how or why dew forms at certain temperatures.
Dew Point in the Classroom
What did we
observe today?
Moisture in the Air
Humidity
 The amount of water vapor in the air is called humidity.
 When the humidity is high, there is more water vapor in the air.
 When air is saturated, it contains as much water vapor as possible
Relative Humidity
 The amount of water vapor present in the air compared to the maximum amount
of water vapor the air could contain at the temperature is called relative
humidity.
Dew Point
 When the temperature decreases, the
air can hold less moisture.
 The dew point is the temperature at
which air is fully saturated because of
decreasing temperatures while holding
the amount of moisture constant.
1. Under what weather conditions would both the air
temperature and the dew point be the same number?
2. Imagine that you are doing this activity again, on a day with
similar air temperature. If you found that the dew point had
increased, would this indicate that there was more moisture in
the air, or less? Explain.
Clouds
 Clouds are water droplets or ice crystals suspended in the
atmosphere.
 Clouds form when moisture in the air condenses on small
particles of dust or other solids in the air
 A cloud that forms near Earth’s surface is called fog.
How are clouds classified?
Cirrus – feathery of fibrous clouds made of ice
crystals
-indicate that rain or snow will fall
within several hours
Cumulus- fluffy and white with flat bottoms
- associated with fair weather
- produce thunderstorms when they
get larger and darker on the bottom
Stratus- smooth gray clouds that cover the whole
sky
-associated with light rain and drizzle
-result in fog when formed close to the
ground