North Carolina Testing Program EOG Reading Grade 5 Sample Items
Page 1 Published January 2004. May reproduce for instructional and
educational purposes only, not for personal or financial gain.
Cloud
droplet
Mist
droplet
Drizzle
droplet
Raindrop
Droplets come in many sizes. Believe it or not, a raindrop has
about a million times as much water in it as a cloud droplet.
Do you know where rain comes from? Read the following selection to learn more about
precipitation. Then answer the questions that follow.
Precipitation
In Arica, Chile, the average rainfall is
less than 1 millimeter per year. Many years
pass with no precipitation at all. On the
other hand, the average rainfall on
Mount Waialeale on the island of Kauai in
Hawaii is over 12 meters per year. That’s
more than enough to cover a three-story
house! As you can see, rainfall varies greatly
around the world.
Water evaporates into the air from
every water surface on Earth and from living
things. This water eventually returns to the
surface as precipitation. Precipitation (pree
sip uh
TAY
shun) is any form of water that
falls from clouds and reaches Earth’s surface.
Precipitation always comes from
clouds. But not all clouds produce
precipitation. For precipitation to occur,
cloud droplets or ice crystals must grow heavy
enough to fall through the air. One way that
cloud droplets grow is by colliding and
combining with other cloud droplets. As the
droplets grow larger, they fall faster and
collect more and more small droplets.
Finally, the droplets become heavy enough to
fall out of the cloud as raindrops.
Types of Precipitation
In warm parts of the world,
precipitation is almost always rain or drizzle.
In colder regions, precipitation may fall as
snow or ice. Common types of precipitation
include rain, sleet, freezing rain, hail, and
snow.
Rain The most common kind of precipitation
is rain. Drops of water are called rain if they
are at least 0.5 millimeter in diameter.
Precipitation made up of smaller drops of
water is called mist or drizzle. Mist and
drizzle usually fall from stratus clouds.
Sleet Sometimes raindrops fall through a
layer of air below 0°C, the freezing point of
water. As they fall, the raindrops freeze into
solid particles of ice. Ice particles smaller
than 5 millimeters in diameter are called
sleet.
Freezing Rain At other times raindrops
falling through cold air near the ground do
not freeze in the air. Instead, the raindrops
freeze when they touch a cold surface. This is
called freezing rain. In an ice storm, a
smooth, thick layer of ice builds up on every
surface. The weight
of the ice may break
tree branches onto
power lines, causing
power failures.
Freezing rain and
sleet can make
sidewalks and
roads slippery and
dangerous.
3
