Climate can be considered the average
weather conditions over a long period of time. The climate is influenced by
latitude, land and water distribution, altitude, land barrier, air movement,
ocean currents, permanent storm areas, temperature, humidity, precipitation,
cloud cover, high and low pressure centers, and other weather phenomena.
Overall the major control is governed by
solar radiation. This was first recognized by Eratosthenes (276-192BC) who
observed that the angle of the Sun’s rays had something to do with solar
radiation. This in effect is due to the tilt of the Earth on its axis, which
throughout the year causes the change of the seasons. However, do not confuse
seasons with climate. climate has many other factors that have to be
considered. For instance the climate in St. Louis, Missouri, Washington, D.C.
and San Francisco, California are very different, but yet they receive the
same solar radiation. Mountains, closeness to coastal area, and other
parameters can cause very different climate.
Climates can be defined by temperature,
rain, and humidity. We recognize the following: Tropical climates (rainforest,
savanna and monsoon); dry climates (desert and grasslands); mid-latitude
climate (humid subtropical, marine west coast, Mediterranean, and mid latitude
monsoon); and polar including tundra areas which are frozen all year round.
- The internet has a wealth of information
for students to use to develop their own idea of climate. In this exercise the
web sites provide long term information on temperature and precipitation. On
the web site we highly suggest you access data from any year. There is many
ways to have the students interpret this data.
- Students could compare the temperature and/or
precipitation the year they were born and last year.
- Students could look at every 10 years of
temperature and see if the United States is actually "cooling" or
"warming." Debate is sure to occur.
- Students can look at five years in a row, and see
if they could predict the 6th year with that information.
- If you do not have internet access we
suggest that you use the figures included in this lesson and have the students
look at all the states to determine whether it has gotten cooler or warmer.
Use a map of the United States to make sure that students know their states.
You may want them record the information on a blank map or just to just to
gather the data in a data chart.
- The worksheet has the students look at
temperature in the United States in January, 1990 and January, 1996. You
cannot make a "scientific conclusion" from only two data points. To
interpret data you must have sufficient data to make a valid interpretation
that is accurate. New data can sometimes change the interpretation.