Have you bought your science-themed Christmas cards yet? Fear not, you can buy them on Etsy in 2 week’s time…
This year, I’ve worked with snowflake expert Kenneth Libbrecht to bring you the science of snowflakes card set (3 of the 6 card set pictured above). The ink drawings were copied from Kenneth’s incredible snowflake pictures (captured using a specially designed snowflake photomicroscope). Read more about snowflakes on his website: www.snowcrystals.com
As usual, the cards are as environmentally friendly as I can make them at present. All cards:
- are printed on Forest Stewardship Council certified card
- come with a recycled envelope (pictured)
- in a cellophane sleeve (cellophane is made of plant cellulose and is biodegradable)
And each one falls a different way, so no two will ever be the same
Each card comes with a beautiful poem, written by the talented Chris Raymond, which tells the story of where a snowflake comes from and why every snowflake is unique.
In heaven once the six true sides
Of each ice crystal start to grow
Gossamer stems high in the grey
Clouds, they branch and branch again,
And each flake flutters, dances, rides
The cloud-drafts, then fattens, falling slow.
And each one falls a different way
So no two will ever be the same.
But then you knew that, like you know
The ceiling-light from sun on snow,
The country white on Christmas morning,
The air gin-sharp at the year’s turning.
The world renewed: sun-dazzled, linen-soft,
The eye bewitched and the heart aloft.
by Chris Raymond
Where do snowflakes come from? A bit more science
Snowflakes grow high up in supercooled clouds (-10°C). Within these clouds a water droplet freezes and grows into a tiny hexagonal plate, the shape determined by the 6-fold symmetry of frozen water molecules.
Each snowflake’s journey to the earth is different due to many different ways the wind can blow a snowflake through humid, cold, warm, and dry clouds. The wind may blow the nascent snowflake into a humid cloud. The high density of water vapour helps the crystal’s six corners to grow into complex patterns (water vapour has less distance to travel to condense on the points!).
Following the will of the wind the tiny snowflake blows to and fro, each change of direction causes a new pattern to form in the six arms (see Kenneth’s diagram on what shapes different temperatures and humidities cause). As it grows, the heavier it gets, silently falling in a snow flurry onto your mitten.
Each snowflake has an individual journey depending on the will of the wind. As each cloud the snowflake passes through has different properties, each snowflake has a unique pattern: No two snowflakes are alike. (At least it’s highly unlikely that there are 2 the same – it is very hard to test! Kenneth has a whole webpage dedicated to answering the question “is it really true that no two snowflakes are alike?“)
Want more science? Here’s a reference to an article Kenneth has written on snow crystal growth: Kenneth G Libbrecht 2005 Rep. Prog. Phys. 68 855 doi:10.1088/0034-4885/68/4/R03
The cards also have one of these snowflake facts:
How does a snowflake get 12 branches?
Snowflakes with 12 branches are an illusion. They are actually two 6 branched snowflakes that have collided and stuck, their branches growing 30 degrees apart.
If two identical snowflakes fell, who would know?
It is extremely unlikely that two complex snowflakes will look exactly alike. It’s so extremely unlikely that even if you looked at every one ever made you would not find any exact duplicates.
What makes a snowflake form?
The snowflake is a very simple example of self-assembly. There is no blueprint or genetic code that guides the growth of a snowflake, yet marvelously complex structures appear, quite literally, out of thin air.
The final designs are being sent to the printer tomorrow and I’ll let you know as soon as they are available to buy!