LATITUDE AND CLIMATE LOCATION, LOCATION, LOCATION OBJECTIVE: Identify and locate the four special lines of latitude and explain how climate is affected by location.

BELL RINGER  Luis goes to the hardware store to make a purchase. He asked the clerk, “How much will six cost?” The clerk thought for a moment and said, “Three dollars.” Luis then asked, “How much will thirty six cost?” “Six dollars,” replied the clerk. Luis scratched his head and said, “If I bought three hundred sixty, how much would that cost?” “That will cost you nine dollars,” said the clerk. What was Luis buying?

YESTERDAY’S ANSWER  Sid would be 160 cm tall (that’s about 5’3”)  If Sid’s height is 80 cm plus half of his height, then 80 cm must be the other half of his height  = 160

CLASSROOM RULES  Comply with all federal, state and district policies  Do not do anything that creates unsafe or unhealthy conditions in my classroom  Do not do anything that interferes with your learning  Do not do anything that interferes with anyone else’s learning  Do not let anyone else interfere with your learning

CLASSROOM PROCEDURES  Bring and use the proper materials at the proper time  No gum or food  Do not talk except when the activity permits or when you have a question (raise your hand first).  Stay in your seat unless you have permission  Do not do work from other classes unless you have permission  Listen carefully to instructions, execute them to the best of your ability, and ask if you do not understand them  Participate in the lesson by doing the correct activity at the correct time: listen, ask questions, discuss, read, write, research.

VOCABULARY Terms we will be using today  Arctic Circle  Tropic of Cancer  Tropic of Capricorn  Antarctic Circle  Precipitation  Growing Season

THE MAGIC NUMBER  The four special lines of latitude all involve one number: 23.5°  The Arctic Circle is 23.5° from the North Pole  The Tropic of Cancer and Tropic of Capricorn are each 23.5° from the Equator  The Antarctic Circle is 23.5° from the South Pole

WHY 23.5°?

AXIAL TILT IS THE REASON FOR THE SEASONS  Because the Earth’s axis is tilted 23.5°, the angle of the sun’s rays is different at different points on the surface, depending upon where Earth is in its orbit  When the sun shines more directly on the surface, more heat is applied to the surface  When the sun shines less directly (the proper term is “obliquely”), less heat is applied to the surface  In the Northern Hemisphere, the sun shines more directly during April- September and more obliquely during October-March  It’s opposite in the Southern Hemisphere

YOU DO  On your world map  Fill in your name, period and the date  Use a ruler, a folded piece of paper or something else with a straight edge to draw the Equator and the two Tropic lines on the next slide  Help your partner if they need it

LOCATIONS OF THE TROPICS Tropic of Cancer Tropic of Capricorn

AXIAL TILT IS ALSO A REASON FOR CLIMATE  Between the Tropic of Cancer and the Tropic of Capricorn, the sun always shines most directly  There will be two days during the year when the sun passes directly overhead (on the Tropics, it happens once per year and that day is called a “solstice”)  “The Tropics” are sometimes called the “low Latitudes”  Temperatures are generally high with no clear differences between seasons (depending on elevation)  Usually lots of rain and very long growing season  Day/Night are fairly equal, year round and twilight is short

YOU DO  On your world map:  Use a ruler, a folded sheet of paper or something with a straight edge to draw the two Circles on the next slide  Help your partner if they need it

LOCATION OF THE CIRCLES Arctic Circle Antarctic Circle

AXIAL TILT IS ALSO A REASON FOR CLIMATE  Between the Poles and the Circles, the sun always shines most obliquely  There will be one or more days during the year when the sun never rises and one or more days when it never sets  The area is called “Polar” or the “high Latitudes”  Temperatures are generally cold with very long winters and very short growing seasons  Day/Night times are most unequal  Long periods of twilight

LOCATION OF THE TEMPERATE ZONES Northern Temperate Zone Southern Temperate Zone

AXIAL TILT IS ALSO A REASON FOR CLIMATE  Between the Tropics and the Circles are the temperate zones or mid-latitudes  Fairly distinct seasonal temperature differences  Moderate precipitation (either as rain or as snow/ice)  Seasonal differences in the number of hours of day/night  Long or moderate growing seasons  Moderate to long periods of twilight (longer twilight as you move north)

LATITUDE DETERMINES PRECIPITATION?

POPULATION PREDICTIONS  If Latitude affects temperatures (it does) AND  If Latitude affects precipitation (it does) THEN  Where would be expect to find people living?  Many people living in areas where there are moderate temperatures and enough rainfall to support agriculture  Many people living in areas where there are high temperatures and enough rainfall to support agriculture  Few people in areas with moderate temperatures and little precipitation  Few people in areas with low temperatures and lots of precipitation

EFFECT ON PEOPLE

CONCLUSIONS  Latitude has a very strong effect on temperatures, but it is not the only factor  Temperatures are a major factor in the length of the growing season (edible plants do not handle freezing well)  Latitude has a very strong effect on precipitation, but it is not the only factor  Temperature and rainfall determine what kinds of plants can be grown (snow doesn’t help until it melts)  The eastern half of North America has both moderate temperatures and good precipitation, so we expect to find many people and there are

HOMEWORK Given a blank world map:  Draw and label:  Prime Meridian  Equator  Tropic of Cancer  Tropic of Capricorn  Arctic Circle  Use a ruler or straight-edge to make the lines (no freehand)  Label:  Atlantic Ocean  Pacific Ocean  Indian Ocean  Arctic Ocean  North America  South America  Europe  Asia  Africa

TOMORROW  We will use Latitude and Longitude as a coordinate system to locate places on the Earth’s surface.