A Article about snowflakes.
http://www.gameleactt.org.uk/articles/2342/1/A-Article-about-snowflakes/Page1.html
Catherine Harris
Hi, my name is Catherine, I am from Tapton Grove in Chesterfield. I am doing Max's 12 week computer course. By Catherine Harris
Published on 01/5/2006
Guide to Snowflakes
... A look at the different types of falling snow ...
Although no two snowflakes are exactly alike, their forms usually fall into several broad categories. Check out the basics below, and then impress your friends with your knowledge of the snowflake menagerie. A printable version follows, which can be used as a field guide when observing natural snowfalls.
These pictures are from the Rasmussen&Libbrecht collection (see Photo Collections). You can find a much more detailed and descriptive field guide in our new book....
The Basic Snowflake Forms
Dendrite means "tree-like", which describes the multi-branched appearance of these snow crystals. Stellar dendrites have six symmetrical main branches and many randomly placed sidebranches.
These crystals are sometimes 5mm or more in diameter, yet they are quite flat and perhaps less than 0.1mm thick.
Numerous ice ridges seem to divide the plate-like arms of these snow crystals into sectors -- hence they are called sectored plates. Like the stellar dendrites, sectored plates are flat, thin slivers of ice that fall to earth in a stunning diversity of complex shapes.
Plate-like snow crystals may get more attention, but columnar crystals are the main constituents of many snowfalls. These hollow columns are hexagonal, like a wooden pencil, with conical hollow features in their ends.
Columnar crystals can grow so long and thin that they look like needles. Sometimes these ice needles contain thin hollow regions, and sometimes the ends split into additional needle branches.
Not all snowflakes form as thin flat plates or slender columns. Spatial dendrites are made from many individual ice crystals jumbled together. Each branch is like one arm of a stellar crystal, but the different branches are oriented randomly.
These crystals started out growing as columns, but then suddenly switched to plate-like growth. This happens when a crystal is blown into a region with a different temperature (see the Snowflake Primer).
Snowflakes grow up in clouds, and clouds are made of small water droplets. Droplets that freeze onto a falling snow crystal are called rime, and these pictures show crystals that picked up different amounts of rime. Sometimes a snowflake becomes just a ball of rime, which is then called graupel, or soft hail.
Snowflakes can have a hard life blowing about in a turbulent cloud, so that many arrive on the ground broken, ill-formed, and generally in bad shape. Warm snowfalls tend to bring the most irregular snowflakes, especially when the wind is blowing hard.
The categories above are just the basic snowflake types. You can see some of the more exotic specimens at Unusual Forms. And for even more, see our new book.
A bit of terminology: What we usually call snowflakes are more accurately called snow crystals, which are single crystals of ice that often show six-fold symmetry (see the Snow Crystal Primer). A snowflake is a more general term that can mean an individual snow crystal, a polycrystalline form like a spatial dendrite, or a cluster of many snow crystals stuck together. One often sees snowflakes that look like puff-balls, sometimes made of thousands of individual snow crystals, falling from the sky.
Guide to Snowflakes
... A look at the different types of falling snow ...
Although no two snowflakes are exactly alike, their forms usually fall into several broad categories. Check out the basics below, and then impress your friends with your knowledge of the snowflake menagerie. A printable version follows, which can be used as a field guide when observing natural snowfalls.
These pictures are from the Rasmussen&Libbrecht collection (see Photo Collections). You can find a much more detailed and descriptive field guide in our new book....
The Basic Snowflake Forms
Dendrite means "tree-like", which describes the multi-branched appearance of these snow crystals. Stellar dendrites have six symmetrical main branches and many randomly placed sidebranches.
These crystals are sometimes 5mm or more in diameter, yet they are quite flat and perhaps less than 0.1mm thick.
Numerous ice ridges seem to divide the plate-like arms of these snow crystals into sectors -- hence they are called sectored plates. Like the stellar dendrites, sectored plates are flat, thin slivers of ice that fall to earth in a stunning diversity of complex shapes.
Plate-like snow crystals may get more attention, but columnar crystals are the main constituents of many snowfalls. These hollow columns are hexagonal, like a wooden pencil, with conical hollow features in their ends.
Columnar crystals can grow so long and thin that they look like needles. Sometimes these ice needles contain thin hollow regions, and sometimes the ends split into additional needle branches.
Not all snowflakes form as thin flat plates or slender columns. Spatial dendrites are made from many individual ice crystals jumbled together. Each branch is like one arm of a stellar crystal, but the different branches are oriented randomly.
These crystals started out growing as columns, but then suddenly switched to plate-like growth. This happens when a crystal is blown into a region with a different temperature (see the Snowflake Primer).
Snowflakes grow up in clouds, and clouds are made of small water droplets. Droplets that freeze onto a falling snow crystal are called rime, and these pictures show crystals that picked up different amounts of rime. Sometimes a snowflake becomes just a ball of rime, which is then called graupel, or soft hail.
Snowflakes can have a hard life blowing about in a turbulent cloud, so that many arrive on the ground broken, ill-formed, and generally in bad shape. Warm snowfalls tend to bring the most irregular snowflakes, especially when the wind is blowing hard.
The categories above are just the basic snowflake types. You can see some of the more exotic specimens at Unusual Forms. And for even more, see our new book.
A bit of terminology: What we usually call snowflakes are more accurately called snow crystals, which are single crystals of ice that often show six-fold symmetry (see the Snow Crystal Primer). A snowflake is a more general term that can mean an individual snow crystal, a polycrystalline form like a spatial dendrite, or a cluster of many snow crystals stuck together. One often sees snowflakes that look like puff-balls, sometimes made of thousands of individual snow crystals, falling from the sky.