Lesson 2 (Processes That Shape the Earth – Weather)
What is the relationship between differential heating and
convection?
How do differential heating and convection affect the earth’s
weather patterns and winds?
How do global patterns of atmospheric movements affect
weather?
Differential heating- differences in the amount of
heat received when different surfaces are heated by
the sun.
a) Light surfaces heat less than dark
surfaces.
Example: snow will heat less than soil
b) The sun’s energy is spread out over a large
area, so it heats the Earth’s surface
unevenly.
c) The equator receives the most direct
sunlight.
d) The sun’s rays strike the north and south
pole at a lower angle.
e) The temperature at the north and the
south poles are much cooler than at the
equator.
Convection- The transfer of heat by the motion within
a fluid.
a) Convection is heated matter that rises
while cooler matter sinks. (**think back
to air pressure**)
Wind – Air in motion produced by the uneven heating of
the Earth’s surface by the sun.
a) The ultimate source of energy that
powers winds is the sun.
What causes the wind to blow?
a)
b)
c)
d)
e)
f)
All winds are caused by differences in air
pressure.
Some parts of the Earth receive indirect rays
from the sun, so the climate is colder. Some
parts of the Earth receive direct rays from the
sun all year and are always warm.
Land heats up and cools off quicker than water.
Warm air rises because it weighs less than cold
air.
Then cool air moves in and replaces the rising
warm air.
This movement (convection currents) of air is
what makes the wind blow.