Transcript ppt temp and humidityx

Warm up
Go to the website classtools.net
In your notebook, create a set of questions and answers using your
vocabulary words. This should be set up as question then answer (not
multiple choice). The number of questions/answers depends on the
game or activity you choose to create.
Input your questions and answers into one of the games or activities at
classtools.net
Follow the directions to save your game/activity
Email the link/access to the game to Mrs. Chapel
You have 15 minutes
Review
• Local and global winds:
Worksheet for sea breeze/land breeze
• Mountain breeze/sea breeze: draw a diagram for each of these and
place the diagram in the basket
• The Coriolis effect:
Go to my links and play the interactives titled
Global winds interactive and Global winds interactive 2. Show me your
score for each one when you finish
Warm up
• Go to my links and play the games/crossword puzzles listed there
1. Which statement describes the
general movement of air masses?
a. They move from areas of high
pressure to areas of low pressure
b. They move from areas of high
altitude to areas of low altitude
c. They move from areas of low
humidity to areas of high
humidity
d. They move from areas of low
temperature to areas of high
temperature
2. What type of weather would you
expect to experience if a weather
map indicated that we are having a
high pressure system in our area?
a. Storms and rain
b. Mostly cloudy
c. Sunny and clear conditions
d. None of the above
3. In which atmospheric layer of
Earth do thunderstorms occur?
a. Stratosphere
b. Thermosphere
c. Ionosphere
d. troposphere
Topic 1: Measuring Temperature
• Thermometer: Mechanical or electrical device for
measuring temperature. Early thermometer was invented
by Galileo.
• Most things expand when heated-this is how a
thermometer works
• On a weather map=lines connecting equal temperatures
are called isotherms
Celsius Scale
• Celsius Scale: Most commonly used scale. Unit of temperature is called a degree.
Based on the boiling and freezing points of water.
• Boiling Point: The temperature at which water boils. 100 degrees C at sea level.
• Freezing Point: The temperature at which water freezes. 0 degrees C at sea level.
Fahrenheit
• Official scale used by meteorologists in the US, Unit of temperature is
called a degree.
• Water freezes at 32 degrees
• Water boils at 212 degrees
Kelvin
• Kelvin is another way of measuring temperature.
• Scientists use Kelvin to explain the behaviour of gases.
• “Absolute Zero” is measured in Kelvin – which is the coldest possible
temperature
• 0 Kelvin = -273 ºC
Converting Temperature
• F = 9 C + 32 or F=1.8 C + 32
5
• K = C + 273
• (F-32)/1.8= C
• Water freezes at 32°F, what is this in Celsius?
• In Kevin?
• Water boils at 100°C. What is this in Fahrenheit?
• In Kelvin?
Humidity is:
• A measure of the amount
of water in the
air
• Water is added to the air by the process of
EVAPORATION.
• Measured using a psychrometer or hygrometer
Relative Humidity
• RELATIVE HUMIDITY is the amount of water in the air
compared to the amount of water the air could possibly
hold.
• Humidity values are usually given as Relative Humidity.
• Examples:
• if the air is holding half the water it could hold, it’s Relative
50%.
Humidity is
• If the air is holding ALL the water it can hold it is saturated and
the relative humidity is 100%
• If the air is holding no water, relative humidity is 0%
• If it holding a quarter of the water it could hold, 25%
Measuring Humidity
• Relative Humidity is measured using a PSYCHROMETER.
• A psychrometer is made of two thermometers. One is
covered with a wet cloth. When air moves over the wet cloth,
evaporation occurs and lowers the temperature on that
thermometer. If you compare the temperature on the two
thermometers you can get the relative humidity.
Condensation
• Condensation is the process by which a gas, such
as water vapor, becomes a liquid.
• Condensation will occur when the air is SATURATED,
or has a relative humidity of 100%. The air can’t hold
any more water vapor, so the water condensed out of
the air. This commonly happens when moist air is
cooled, or comes in contact with a cool surface.
Dew Point
• DEW POINT is the temperature
at which condensation will
occur. The Dew point is the
temperature the air must be in
order to be saturated.
Remember, cooling the air
makes it unable to hold as
much water vapor, so water will
condense out at a certain
The ice makes the air
temperature.
near the glass cooler
and it reaches its’ dew
point, cool air can’t hold
as much moisture and
condensation occurs
How humid is “VERY” humid?
• The human body cools down through perspiration (evaporation of
body liquids from the skin surface).
• If the relative humidity is high, the evaporation is inhibited and we
cannot cool efficiently. The body temperature rises.
• Heat Index: shows what the air temperature feels like. It takes into
account the humidity and the actual temperature of the air.
• Humans feel comfortable if HI<80 F. Heat index above 90 F is
uncomfortable. HI>100 F is dangerous.
Water vapor and Air pressure?
• At the same temperature, a column of dry air will be denser or
heavier than a column of air containing any water vapor.
• When you add water molecules to air, some of the nitrogen and
oxygen leave. They are “bigger” than water molecules, so adding
water vapor to air makes it less dense.
• As the temperature rises the proportion water vapor in the air
increases, its buoyancy will become larger.
Warm up
• Your warm up is at your seat
• you have 10 minutes
Closure
• As the amount of moisture in the air increase, the density of the
air_____________
a. Increases
b. Decreases
c. Stays the same
d. Doubles
Air masses
• Maritime=
• Tropical=
• Continental=
• Polar=
• Arctic=
Air Masses…
• Continental Tropical
•
•
•
•
•
Abbreviation - cT
Origin - land
Origin - tropical
Moisture Content - dry
Temperature - warm
http://earth.usc.edu/~stott/Catalina/WeatherPatterns.html
Air Masses…
• Maritime Tropical
•
•
•
•
•
Abbreviation - mT
Origin – ocean/water
Origin - tropical
Moisture Content - humid
Temperature - warm
Air Masses…
Continental Polar
•
•
•
•
•
Abbreviation - cP
Origin - land
Origin – high latitudes
Moisture Content - dry
Temperature – cool or cold
Air Masses…
• Maritime Polar
•
•
•
•
•
Abbreviation - mP
Origin – ocean/water
Origin – high latitudes
Moisture Content - humid
Temperature – cool or cold
Air Masses…
• Arctic (Continental)
•
•
•
•
•
Abbreviation - A
Origin – land
Origin - Arctic
Moisture Content – dry
Temperature – very cold
Air fronts
• A front is simply the boundary between two air masses.
http://3.bp.blogspot.com/_275ZCyVPoFk/TNAxxCklePI/AAAAAAAAAJs/VFM3DzpqDzg/s1600/meteo.jpg
http://www.cdli.ca/courses/sci2200/unit02_org01_ilo03/b_activity.html
Cold Front…
• Definition – Cold, dense air displaces warm air and forces it up a
steep front
• Symbol – blue icicles!
• Weather – clouds, showers, and thunder storms
http://earth.usc.edu/~stott/Catalina/WeatherPatterns.html
http://www.cdli.ca/courses/sci2200/unit02_org01_ilo03/b_activity.html
Warm Front…
• Definition – Advancing warm air displaces cold air and moves up
slowly
• Symbol – red lava rocks!
• Weather – extensive cloudiness and precipitation
Stationary (Stalled) Front…
• Definition – Two air masses meet and neither advances
• Symbol – blue icicles alternate with red lava rocks
• Weather – some clouds and precipitation
http://www.nvwx.com/wximages/occluded_front.png
Occluded Front…
• Definition – A cold air mass moves so rapidly that it overtakes a
warm front and wedges the warm air up.
• Symbol – purple alternating rocks/icicles
• Weather – precipitation on both sides of the front
Closure activity
• There are 16 QR codes around the room. Use the computer to
answer 8 of the questions and turn the answers in as part of your
closure.