By Karen Rice
Official Kids Mag
They say that no two snowflakes are
alike, but with trillions falling every year,
how do we know? First, it helps to know
more about how snowflakes are made.
When the air is colder than 0° Celsius
(or 32° Fahrenheit), snow crystals
begin to form from water vapor high in
the atmosphere. As more water vapor
condenses and freezes on these crystals,
they form the beautiful shapes and
branches we call snowflakes!
Surely some snowflakes have to be
exactly the same, right? Nope!
Although snowflakes are all the same
on an atomic level (they are all made
of the same hydrogen and oxygen
atoms), it is almost impossible for two
snowflakes to form complicated designs
in exactly the same way. It is estimated
that there are 1018 water molecules
in a snowflake, and they can arrange
themselves in an almost infinite number
of ways.
Snowflakes come in many shapes. The
most beautiful are the "stellar dentrites"
with six branches, what we think of as
a classic snowflake. But snowflakes can
also form prisms, needles, columns and
six-sided plates.
The science behind how snowflakes
form is complicated. Temperature
Is it true that
snowflake formation varies with air
temperature and humidity. What shape
might you see if it were -13°c with low
humidity?
studies among the snow crystals. Wilson Bentley, "the
snowflake Man," 1902. noaa photo library.
has the most effect on the shape of a
snowflake. Scientists aren't sure why ice
crystals take different shapes at different
temperatures. Humidity, or the amount
of moisture in the air, affects how
complex a snowflake will be.
And, since snow crystals blow around
inside a cloud before they fall to the
ground as snowflakes, it's almost
impossible for two crystals to experience
exactly the same environment.
Also, as a snowflake falls from the
cloud, it encounters various other
elements such as more freezing water
vapor, winds and temperature changes.
Each snowflake takes a slightly different
journey, and the difference causes the
snowflakes to change as they fall and
grow larger.
Check it out for yourself. If you're
lucky enough to see snow this year, put
a piece of cardboard in the freezer (so it
gets cold and won't melt the snowflakes)
and then catch a few flakes on the
cardboard. Use a magnifying glass to get
a good look at each unique snowflake
up close and personal.
Read on, for the story of Wilson A.
Bentley, who probably heard the saying
"no two snowflakes are alike" as a boy.
Wilson, however, went one step farther.
He set out to prove it.
Wilson Bentley prepares
to photograph a snowflake
using his microscope-bellows
camera.
no two snowflakes
are alike?
source: Kenneth libbrecht; Images: ©Kenneth libbrecht/science source
46 • January 2021 • www.officialKidsMag.com
