Why the Equator is Hotter
than the North Pole
YOU NEED
Here is why he direct rays of the sun are hotter than
slanted rays.
What to do: Shine the flashlight straight down on the sheet
of paper. Then tilt the flashlight so its rays strike the paper
at a slant, as in the illustration below.
What happens: When you point the flashlight straight
down, it makes a small circle of light on the paper. When
you tilt the flashlight so its rays strike the paper at a slant, it
makes a larger, dimmer, oval shape.
Why: both the oval and the circle were made by the same
source of light (the flashlight). Therefore, the oval has the
same amount of light as the circle. But since the oval is
bigger, the light in it must be spread more thinly.
In the same way, a slanted ray of sunlight spreads out more
thinly over the earth's surface than a ray that shines straight
down. While both rays carry the same amount of heat from
the sun, the heat carried by the slanted ray is spread out
and less intense.
So, places at and near the equator—where the sun shines
directly—get two-and-one-half times as much heat as the
North and South Poles where the sun always shines
indirectly.
•flashlight
•sheet of paper
Directly overhead,
the energy of the
sun’s rays are
concentrated in a
smaller area.
At an angle, the
energy from the
sun’s rays is spread
over a much wider
area, so any given
point receives less.