THE SEASONS - quia.com · SEASONS? •TRUE OR FALSE: –Because the Earth is closer to the sun in...
Transcript of THE SEASONS - quia.com · SEASONS? •TRUE OR FALSE: –Because the Earth is closer to the sun in...
THE SEASONS:
The tilt of the Earth’s
Axis, Reflection, and
absorption
WHY DO WE HAVE
SEASONS?
• TRUE OR FALSE:
– Because the Earth is closer to the sun in
summer than in winter.
ANSWER:
FALSE!!! The Earth is actually approx.
3% closer to the sun in January than it
is in July!!! (don’t feel bad – ¾ of
Harvard grads got this wrong (on
camera!)
KEY FACT: • THE EARTH’S AXIS IS TILTED 23.5O TOWARDS THE NORTH
STAR*, BUT NOT ALWAYS TOWARDS THE SUN:
-SOMETIMES IT’S TILTED TOWARDS THE SUN (SUMMER)
-SOMETIMES IT’S TILTED AWAY FROM THE SUN (WINTER)
-SOMETIMES IT’S TILT IS “IN BETWEEN” TOWARDS AND AWAY
(SPRING AND FALL)
The angle of sunlight: direct or not? This
makes all the difference!
SUMMER: a closer view…
Sunlight hits the
Earth’s surface at a
DIRECT angle, so the
energy is
CONCENTRATED,
causing WARMER
TEMPERATURES
WINTER: a closer view…
Sunlight hits the
Earth’s surface at an
INDIRECT angle, so
the energy is NOT
CONCENTRATED,
causing COOLER
TEMPERATURES
Concentration of rays
determines temperature
SPRING AND FALL:
a closer view…
This causes the Energy to reach
the ground “SOMEWHAT
CONCENTRATED” (more than
in winter, less concentrated
than in summer)
sun
TROPICS/EQUATOR – ALWAYS MOSTLY DIRECT = HOT;
ARCTIC CIRCLES/POLES – ALWAYS MOSTLY INDIRECT = COLD;
MIDDLE LATITUDES – BETWEEN CIRCLES AND TROPICS – VARY
BY SEASON