A good night’s sleep!

A good night’s sleep!

I awoke this morning to find NO CHILDREN at all in my bed.  A very rare event indeed.  I can’t remember the last time that happened but I am certainly not complaining.  It was lovely to have a full night’s sleep with no interruptions for a change.  I was perfectly happy to have little Rohan crawl into bed beside me at the reasonable hour of 7 am for a cuddle.  Turns out it wasn’t Rohan but a “baby Dolphin” and I was the “Mammy Dolphin” and the bed was actually the sea.  It did not take long for Rohan’s clever little mind to start to wonder….

……………………. “HOW DO DOLPHINS SLEEP IN THE SEA, MAMMY?”

 

photo credit: Leo Reynolds via photopin cc
photo credit: Leo Reynolds via photopin cc

SO, HOW DO DOLPHINS SLEEP?

Dolphins (and whales) are mammals just like us, they need to breathe in air.  Unlike us, dolphins have adapted their bodies breathing system (respiratory system) to be able to go long periods between breaths.  This allows them to stay under water for up to 30 minutes at a time before they need to surface and take the next breath.  The other difference between dolphins and other land mammals is that we breathe involuntarily (without thinking about it) while they make a conscious decision to take a breath.

 

 

HOW CAN DOLPHINS SLEEP IF THEY NEED TO STAY CONSCIOUS TO BREATHE?

Dolphins have overcome the problem of having to stay conscious to breath by only shutting down one half of their brains at a time while sleeping.  This process is called unihemispheric sleep and basically means that one half of the brain sleeps while the other half stays awake and alert.  Interestingly, one eye stays open while the dolphin sleeps, it is the eye on the opposite side to the sleeping brain.  This allows the dolphin to stay alert to its environment at all times, a requirement necessary for its survival.

Scientist determined unihemispheric sleep in dolphins by monitoring brain activity in captive dolphins using a process called electroencephalography.  This process involves attaching electrodes to the dolphins head and tracking brain wave activity as electrical pulses. Such research suggests that dolphins are in this sleep state for approximately eight hours a day.

Studies into the unihemispheric sleep patterns of some mammals suggest hopeful correlations and potential solutions to human sleep disorders such as narcolepsy.

WHERE DO DOLPHINS SLEEP?

There is no real reason why dolphins can’t sleep anywhere within the ocean, but, given that they need to surface fairly frequently to breathe, it is most likely that they sleep just below the surface.

DO ANY OTHER ANIMALS SLEEP LIKE THIS?

Mammals, other than dolphins, that use unihemispheric sleep include whales, porpoises, manatees, sea lions and seals.

This types of sleeping has been observed in some birds and is suggested as a probable form of “sleeping on the wing” for migrating birds.

 

"Tooth & Nail"

"Tooth & Nail"

We waited a long time for my sons front tooth to finally come out – it spent the last week sticking horizontally out of his mouth – in a “Nanny Mc Phee” kind of fashion! Finally, last week, it did come out and there was great salutation and rejoicing – from me anyway.  With suitable formality and ceremony the said tooth was placed in the very special “tooth bag” that we have for such occasions and carefully placed under his pillow.  As I lay with him that night we chatted about all things “toothy” and just before I kissed him goodnight he threw me one of his wonderful questions…..

“MAMMY, HOW COME THE TOOTH FAIRY COMES WHEN WE LOOSE A TOOTH BUT IF WE LOOSE A NAIL THERE IS NO NAIL FAIRY?”……

Look at that for a smile!

Well, where do you start with that one?  I hummed and hawed and spluttered and muttered some kind of an answer (which of course was countered and refuted) and beat a hasty retreat.  The next day we went to visit family only to be met by another toothless smile from my lovely nephew.  So naturally teeth were a hot topic of conversation for the weekend, so much so that my brother suggested they become the topic of my next blog.  Not terribly enamoured with the idea (or should I say “enameled”) I changed the subject.  However, the seed had been sown and the idea rattled around in my head for a few days.  Today I have been chatting with my brother again, he has his own tooth woes this week with a few trips to the dentist and a tooth that didn’t fall out naturally.  So, I figure I owe it to him….this ones for you Bro!

In for a penny-in for a pound… I guess I may as well keep my own son happy too and consider his question, so teeth and nails and the science there-of…although I make no promises on the whole “nail fairy” thing!

WHY DO CHILDREN LOOSE THEIR “BABY” TEETH?

When teeth begin to grow in a baby’s mouth the gum and jaw are not developed enough to allow for extensive roots to form under the tooth and so smaller, weaker roots are formed on these early teeth.  By the age of (usually) six or seven the jaw has matured to a point that allows it to hold adult teeth- and their larger roots- securely.  The smaller baby teeth start to get loose at this stage and fall out.  Cue the “Tooth Fairy”!

WHEN DO BABY TEETH START TO FORM?

Baby teeth start to form when the baby is still in the womb, in fact the first part of their production begins when the fetus is only four weeks old.  Once the baby is born the teeth usually start to push through the gum any time from about six months on.  However there are exceptions to this – some babies are born with visible teeth – these are called natal teeth.  Teeth sometimes appear within the first month after the baby is born and these are referred to as neonatal teeth. The full compliment of 20 baby teeth are usually all grown by age three.

Baby teeth usually fall out in the order in which they first appeared!  Babies who get their teeth later than most will usually start to loose their teeth at a later stage too.  This is certainly true in our house… my daughter finally cut her first tooth at the age of 11 months and lost her first baby tooth at the age of eight!

HOW LONG DOES THE “LOOSING BABY TEETH” PHASE LAST?

Loosing baby teeth and growing new ones usually takes six or more years.

The new adult teeth tend to be less white than baby teeth, often appear very large in the child’s mouth (at first anyway) and usually have noticeable ridges on them (that is because they have not been worn down from chomping and chewing)!

Adult teeth do not actually push their predecessors out of the gum.  Instead a group of cells called odontoclasts form between the root of the baby tooth and the tip of the adult tooth.  These cells are responsible for absorbing the roots of the baby teeth, leaving them without their anchor in the gum.

HOW MANY ADULT TEETH DO WE END UP WITH IN TOTAL?

The 20 baby teeth are ultimately replaced by 28 adult teeth.  Then the four wisdom teeth get added, usually in our 20’s, bringing the total number of adult teeth to 32!  However it is common for some, or all of the wisdom teeth to be completely absent from an adult.  This may happen if the jaw is not big enough to accommodate the extra teeth. I myself got my wisdom teeth very late (and slowly) and only got three of them- I like to think I am wise enough not to need them all – but there are plenty who will argue that one!

WHAT ARE THE DIFFERENT TYPES OF TEETH?

A full set of baby teeth is made up of …

8 X Incisors
4 X Canines
8 X Molars

A full set of adult teeth contains…

8 X Incisors
4 X Canines
8 X Premolars
8 X Molars
4 X Wisdom teeth

Adult human dentition: image credit – www.tutorvista.com

INCISORS are for cutting.
CANINES (also known as CUSPIDS) are used for tearing.
PREMOLARS (also known as bicuspids) are used for tearing and crushing.
MOLARS are ideal for crushing and grinding.

WHAT ARE TEETH MADE OF?

Teeth have two parts, the top part that we can see, called the crown and the part we cannot see, the root, which below the gum.  The root is embedded in the jaw bone.

Image Credits: www.enchantedlearning.com

Teeth are made up of…

ENAMEL…this is the shiny white part of the tooth that we brush.  It is the strongest material in our bodies which makes it ideal for all the cutting, chewing, chomping and grinding that the teeth have to do.  This layer contains a lot of calcium.

DENTINE… this is the layer just under the enamel.  It actually makes up most of the tooth.  Although a hard substance it is not as hard as enamel.

CEMENTUM… this covers the dentine part of the root of the tooth (below the gum) and helps to anchor the tooth into the jawbone.

PULP… this is the inner most part of the tooth.  It is the only living part of the tooth, made up of blood vessels and nerves and other soft tissues.

………………………AND NOW FOR A LITTLE BIT OF NAIL-SCIENCE…

WHY DO WE HAVE NAILS?

Why do we have nails and what purpose do they serve us?  Nails are considered a protective layer at the sensitive ends of our fingers and toes.  However their function goes well beyond protection, they are also great tools and implements for finer dexterity such as peeling, gripping and scratching.

WHAT ARE NAILS MADE OF?

Nails are made up of layers of protein called Keratin, this is the same protein that hair is made of and that we find in the outer layer of our skin.  The different sections of the nail are described below:

Image credit: www.scholl.com

The nail plate-  is the part of the nail that we see, made of layers of keratin.
Nail folds – this refers to the nail skin around the nail.
Cuticle – this is the tissue that covers the bottom of the nail to protect the newly formed nail cells.
Nail bed – this is the are of skin that is covered by the nail.
Lunula – this is the white “half moon” that we see at the base of the nail.

HOW DO NAILS GROW?

Nails do not actually grow from the top of the nail, they grow from the base of the nail, just under the skin.  As new cells are made the older cells harden and get pushed out along the nail.

Fingernails grown about 3 milimetres per month.  Usually fingernails grow faster than toenails.  The fingernails on our dominant hand  grow more quickly than the nails on the non-dominant hand (American Academy of Dermatology).

WHAT CAN OUR NAILS TELL US ABOUT OUR HEALTH?

Healthy nails are smooth and uniform in colour.  Sometimes our nails get little white spots due to knocks and damage and these usually grow out of the nail with time.  Nails may often develop ridges running from base to top, often becoming more dominent with age but these ridges are usually harmless.  However notable changes to the overall colour or shape of the nail or surrounding skin can be more serious and such things should always be brought to the attention of a doctor (Mayo Clinic).

SO BACK TO THE ORIGINAL QUESTION…. WHY TOOTH FAIRIES BUT NO NAIL FAIRIES?

To address the original question of why we have tooth fairies but not nail fairies…. I am still not much the wiser.  We could argue the value in a beautiful baby tooth, sparkling and white, full of calcium and minerals … all which might be of interest to the fairies.  I really like the suggestion in Rise of the Guardians, that fairies take children’s teeth to guard the memories contained within.  When you consider that they are made before we are even born then there is a strong argument to this proposal.

Image credit: greenpoint dental

But as for nails?  I’m not so sure of this one.  Most of what we call a nail is actually a clump of long dead cells.  You could argue that the fairies might like to collect the Keratin that is found in our nails but this is already freely available from our hair, which we shed a lot of and is easily collected, if the fairies were so inclined!  Some say that our toenails are of value as they are the part of our bodies that accumulates any gold, but I can’t find any strong evidence to back this one up.  I have to conclude that fairies just do not have any interest in our nails, to be honest I would not greatly blame them, would you?

AND FINALLY AN EXPERIMENT TO TRY AT HOME:

Here is an experiment that can demonstrate to children what fizzy drinks can do to our teeth.

What you need:

3 hard-boiled egg (shell still on)
3 jars or glasses
A bottle of vinegar
A bottle of fizzy drink
A bottle of water (or tap water will do)

What to do:

Place a hard boiled egg into each of the three glasses.  Cover one egg with vinegar, one egg with fizzy drink and one egg with water.  Cover all three glasses and leave them like this overnight.  Next day remove each egg and record what you find.

What happens:

If you examine the egg in the vinegar you should see that the shell has disappeared.  If this is not the case, place the egg back in the glass and leave it for another day.

The vinegar is an acid (acetic acid); it reacts with the calcium in the egg shell (calcium carbonate) and breaks it down, producing a gas as it does so.  You may have observed the gas as bubbles being formed, during the experiment.  Effectively the vinegar (acid) eats away at the egg shell until it is all gone.

Now look at the egg that was left in the fizzy drink.  You should see that the shell has been dissolved away (or at least partially) just like the vinegar.  The enamel of our teeth contains a lot of calcium just like the egg.  The fizzy drink is acidic, just like the vinegar.  You begin to get an idea of what fizzy drinks can do to our teeth if we don’t look after them!

Now check the egg that was left in water, it should still contain a strong shell, the water should not have changed it!

Further Reading:

Teeth and eating.
Tooth anatomy.
Discovery Health.

Pancakes- everything you didn’t realise you needed to know

Pancakes- everything you didn’t realise you needed to know

Ok, this week’s blog inspiration is slightly different to the norm.  Usually the idea comes from a question that a child has posed – this time there is a slight deviation, but only slight…. this weeks question came from an adult, but only in the chronological sense – as in fact he is classified as the biggest kid in our house- it was posed by my husband.  I was making pancakes the other morning (as I do every weekend on the request of my son) when my husband pondered aloud…”I wonder what the reason behind each ingredient is… and who made the first pancakes”.  As I was wondering what next to blog about the two ideas seemed to merge into one, and so was born the question…..

…..”WHAT IS THE SCIENCE BEHIND A GOOD PANCAKE, AND WHO’S IDEA WAS IT?”…..

Made in the name of science

A BIT OF HISTORY…

So, before I delve into the science behind the PERFECT PANCAKE, I thought I’d look at a little bit of history first.  The pancake as we know it seems to be accredited to the ancient Greeks, who in the 6th century started combining ground wheat with olive oil, honey and milk – and so the first pancake was born. If we expand on our concept of what a pancake really is we could look back further still to the process of making flat bread from ground grains and nuts mixed with milk or water, dating back to the neolithic period.

WHAT DO WE FIND IN A MODERN PANCAKE?

If we start within Europe a modern pancake can be classified as the round flat variety similar to the french crepe which contains some form of flour, and a liquid such as milk or water.  These flat pancakes usually also contain eggs and butter, and sugar in the sweetened variety.  Then we also have the thicker, fluffier pancakes that contain a raising agent, the name and variation of these include drop scones, Scottish pancakes and of course the well know buttermilk pancakes that are most common in America.

In our house the three most common pancakes made are the buttermilk pancakes, drop scones and the sweet flat crepe like ones.

WHAT GOES INTO A PANCAKE…

If we take a closer look at the primary ingredients we begin to see the complexity and science that really goes into making these delights:

FLOUR… this ingredient can be considered the backbone of the pancake as it provides structure
SUGAR….as well as adding the nice sweet taste and contributing to the colour of the pancake, sugar also keeps the pancake from getting to thick and stodgy
EGGS…. the proteins in the eggs add to the structure of the pancake and to the overall flavour
BUTTER/FAT… as with the sugar, the fats keep the pancake tender and prevent them becoming overly stodgy
MILK/WATER… the liquid portion of the pancake adds to the structure and is necessary for certain chemical reactions to occur
RAISING AGENT…  as the name suggests, these agents help raise the pancake, making them light and fluffy

You can of course find many varieties with their own local changes and substitutes, potatoes are commonly used as the starch ingredient instead of flour.

First lets take a look at the thin flat pancake or crepe… in this case we will assume they contain flour, milk and sugar.  From the above list we can now predict that the flour is the body of the pancake, it provides the structure, but how does it do this?  There are two proteins found in flour called glutenin and gliadin.  When moisture is added to flour (in this case the milk) these two proteins link together to form gluten.  Gluten is a “sticky” protein, this stickiness allows it to form a network and it is this that adds structure to the batter.  Finally we come to the sugar which caramelizes with the heat adding sweetness to the mix and contributing to the colour of the pancake as it cooks.  The sugar also prevents the pancakes becoming too thick and stodgy by reducing the amount of gluten produced.

Image credit: jbeancuisine.com

So now we move on to the thicker pancakes; the main difference with these is that they contain a raising agent!  Yeast is a biological raising agent used in some baking, it produces carbon dioxide gas while digesting sugar and this gas forms tiny bubbles within the yeast.  When heat is added during baking these bubbles expand making the bread/cake “rise”.

The main drawback with baking with yeast is that it requires time and who really wants to wait too long for their breakfast?  That is why, when using raising agents in pancake mixtures, we substitute the yeast for bread soda and/or yeast; but who can really tell what the difference is between these two?

Bread soda verse baking powder

Bread soda (also known as baking soda) is pure sodium bicarbonate. Baking powder contains bread soda but it also contains a powdered acid (usually cream of tartar – potassium bitartrate).  Bread soda is an alkali/base and will therefore react with an acid (such as the buttermilk used in pancake batter) producing salt, water and carbon dioxide gas…

BREAD SODA + ACID —–> SALT + H20 + CO2

This carbon dioxide gas gets trapped in thousands of tiny bubbles within the gluten making the pancake batter rise on cooking into light and fluffy wonders!  (The same process as with the yeast but a lot quicker).

The baking powder has the added advantage of having the acid already present, so once a liquid is added the dry acid and alkali can react in the same manner as above.

So now that we are starting to understand the science of it all how do we use this knowledge to make the best pancakes.  before we jump into this one we first have to consider the science of flavour and odour!

THE SCIENCE OF FLAVOUR

The Maillard reaction describes a chemical reaction requiring certain amino acids and sugars and the addition of heat to produce the molecules responsible for the odours and flavour of food.  Now there is a science worth studying!

MAILLARD REACTION:  Amino Acids + sugar + heat —-> flavour and odour

So what does this have to do with our pancakes?  Well Maillard reactions work best in alkali conditions so bread soda is a definite plus is making golden tasty treats.  HOWEVER, add too much bread soda and the pancake will brown too quickly and will have an acrid burnt flavour, not to mention the unpleasant taste produced from the left over breadsoda.  It is trickier than we think and yes, of course, someone has already done the science bit for us to work out the ideal amount of bread soda required.

WE ARE HUNGRY – SPEED IT UP

You will be glad to hear that speed is recommended when preping pancakes;  Although it is good to allow the batter sit for a few minutes to allow the gluten to “relax” (build up a sufficient network) it has been shown that if left too long the bubbles will have burst and the pancakes will be flat and dense once cooked.

SCIENCE IN MY KITCHEN

I decided I had to try some of this pancake science out for myself so turned to my original buttermilk pancake mix from the wonderful NIGELLA LAWSON.  This recipe actually uses both baking soda and baking powder (I omitted the banana).  I decided to test out two theories…

1.  Does the amount of bread soda determine the colour and flavour of the pancake?
2.  Does the length of time the batter is left standing really make that much of a difference?

To keep it simple, I decided to keep everything else (including the amount of baking powder) constant.
So I donned my apron in favour of my labcoat and I set to work.  I prepared the basic batter mix excluding the addition of bread soda.  To digress for a moment, I also followed another golden pancake rule – not to over-mix the batter (a few small lumps of flour allows it better absorb the liquid and produce gluten).

My “slighlty lumpy” pancake batter

I dived my basic batter mix between four bowls and then added different amounts of bread soda to each (the first bowl had no bread soda, the second had half the recommended amount, the third had the recommended amount and the fourth had double what was recommended!).  Then I let the batter sit for five minutes before cooking the pancakes.

Here are my results…  the pancake on the top left had no bread soda, top right had 1/2 the recommended amount, bottom left had the ideal amount and bottom right had twice the recommended amount.  You can see how the pancake gets darker with the addition of more bread soda, with the last one being just a bit too dark.  The taste test revealed that the one on the bottom left had the best taste (and texture) and that the one with the most bread soda had that unpleasant taste of bread soda!

To investigate my second question I left the same pancake batters sit for two hours before cooking them.  As you can see the pancakes cooked after two hours were indeed a lot less light and fluffy and were a bit soggy inside!

The batter for these was left sit for five minutes
The batter for these was left two hours

WHY ARE PANCAKES ROUND?

Pancakes are round for two main reasons: gravity and surface tension.  Assuming that the pancake pan is flat then once the batter is added gravity will pull on all parts of the batter uniformly in all directions, pulling it out into a round shape.  Surface tension pulls evenly on the edges keeping them restrained into the round shape.

THE SCIENCE OF FLIPPING A PANCAKE…

Would you believe that someone has actually looked into the exact science of pancake flipping?  How cool is that ….

According to University Professor of Mathematics Frank Smith, the simple mathematical formula for the perfect flip is: L = 4 H /P- D / 2
(L = hand distance from inner edge of the pancake / H = height of flip / D = diameter of pancake)

If that sounds a bit too complicated check this out …

Dr. Tungate, a senior physics lecturer at Birmingham University, found that “a pancake should be flipped into the air at a speed of 10 miles-an-hour, which means that it takes less than .5 of a second to reach the top of its trajectory.”

AND THEN THERE IS THE SCIENCE OF WHAT YOU ACTUALLY PUT ON YOUR PANCAKES…

… but I think that is a whole other blog! So whatever toppings you choose I hope you enjoy your pancakes today!!

All that science made me hungry!

And if you still want more….HERE IS AN EXPERIMENT YOU CAN TRY….

Inflating balloons… This experiment shows two fun ways of inflating balloons, kids will love it, it’s easy to do and it teaches some kitchen science… like the difference between using yeast and bread soda as raising agents in baking!

Further reading:
Pancakes served with a side of science.
Celebrate your pancakes with a side of science.
Baking powder verses baking soda.
The history of pancakes.

 

There’s "snow" place like home

We were lucky enough to go on a family skiing holiday this January…. sunlight, snow, fresh air, exercise, skiing and just an all round great experience.  I have asked my three children the best things about the holiday and here are their responses….

Caer (age nine)….”relaxing, drinking hot chocolate every day… oh and THE SNOW”
Culann (age seven)….”the snow, eating meat all the time, everything really – except for ski-school!”
…and “Curly” Rohan (age three)….”the hotel, the ski slopes and the snow!”

So a mixed bag of responses there but with the one common denominator… THE SNOW!!!! And who could blame them, I loved it too!  Especially on our last day, the weather got colder and we had a wonderful day of snow.  At lunch time our entire group (15 of us in total) took the cable cars to the top of the mountain for lunch.  The snow up there was thick and deep and as it fell on us we all remarked on the beautiful snow flakes… each one a perfect crystal, large enough to see the tiny branches coming off each arm of the structure.  So the inevitable question came from the children….

……………………..”WHY DOES THE SNOW AT HOME NOT LOOK LIKE THIS?”

A Dendrite Snow Crystal

In order to answer this question we need to understand how snow is made and what can influence this process!  We also need to understand the different shapes that snow can take!

So firstly HOW IS SNOW MADE?…

Snow is made much in the same way as rain, it is created from the moisture that makes up clouds.  Moisture from the earth (seas, rivers, lakes, puddles etc) is constantly EVAPORATING (changing from a liquid to a gas form).  This water vapour (gas) is picked up by warm air and carried to the sky where it forms clouds.  When the temperatures get cold enough the water vapour turns into ice crystals that form around tiny particles of dust or dirt in the atmosphere.  These ice crystals fall to the earth as snow.

So what is the difference between SNOW CRYSTALS and SNOW FLAKES?

A snow crystal is a single crystal of ice that can come in many different shapes.  A snow flake is the term we are more familiar with – it can refer to one snow crystal or a group of snow crystals all grouped together.  Some snow flakes can contain a clump of hundreds of tiny snow crystals.

WHAT ARE THE DIFFERENT SHAPES A SNOW CRYSTAL CAN BE?

When you think of the shape of a snow flake what do you think of?  Do you think of the lovely star like ones with six branches just like the photo above?  This shape of snow crystal is called an HEXAGONAL shape (having six sides) but finding these in such perfect condition is actually quite rare.  With melting and refreezing, wind interference and snowflake collision most snowflakes we see are much more irregular structures.  The snow crystal shown above is a STELLAR DENDRITE which means a star-shaped snow crystal with six branches that have lots of side-branches coming off them (dendrite means tree-like).  More often than not snow crystals are small, NEEDLE, COLUMN or FLAT PLATE shaped and clumped together into one snow flake.  This is certainly what we are more used to in Ireland when it snows.  The array of shapes and sizes of snow flakes is really well described in this  guide to Snowflakes.

                             
                                                                            This is what we saw in Austria!!

The lovely snowflakes that we saw on the top of the mountain in Austria were particularly intricate and beautiful.  I would say they were FERNLIKE STELLAR DENTRITES  and if you are thinking of skiing these are ideal.  There is so much side branching that they look like ferns.  Although these snow crystals are the largest that we see they are actually individual snow crystals which makes them all the more spectacular.  They are often 5 mm or more in diameter and are clearly visible to the naked eye!  So we were really lucky to see these lovely snow flakes.  These crystals are very light and make the best powdery snow!

WHAT INFLUENCES THE SIZE, SHAPE AND SYMMETRY OF A SNOWFLAKE?

So what factors influence the distinctive shape of each snow crystal?  Well for starters there is the temperature at which they form – snow crystals start to form when the cloud temperature reaches or drops below freezing (zero degrees Centigrade (C));  the amount of dust or dirt particles available also effects snow formation.  Then there is the location of the clouds in which the snow crystals form… in general snow flakes are larger when formed in high clouds compared to snowflakes from lower clouds.  This factor links with the length of time the snow flake takes to fall to the ground along with the air temperature as it falls and with how many collisions the snow flakes might encounter.  Snowflakes will often heat and cool as they drop due to differences in air temperature, this often leads to large snowflakes as they become more “sticky” when they melt at the edges, allowing them to clump together as they collide and refreeze.  Other weather factors such as humidity (how much water vapour is in the air) and the wind speed all contribute to the final size and shape of the snowflake formed.

Taking these factors into consideration the lovely fernlike stellar dendrite snowflakes we saw in Austria were probably formed under the following conditions: formed at very low temperatures, in low lying clouds and fell through dry cold air with little wind!

Now lets consider what we are used to here in Ireland!

So this is today’s snow in the west of Ireland!

As I write this I am looking out on a typical “Irish” snow scene… the ground is covered in patchy white snow that is made up of small ball shapes of snow flakes  that are a bit wet and sticky.  On the plus side these make great snow balls… I can vouch for this one myself as my back is still wet from the pelting I got from my husband as he left for work today (the biggest child in the house)!!  So this snow was probably made at lower temperatures in high clouds and melted and froze as it fell to the earth through moist air; this would result in large snow flakes (like small snow balls) made up of a number of small snow crystals joined together.  This snow does not tend to last too long, beginning to melt as it hits the ground, making for that wet sticky snow!

SO IS IT TRUE THAT NO TWO SNOW FLAKES ARE IDENTICAL?

The simple answer to this is YES and NO!  Although we cannot vouch for every single snowflake that ever existed, science does suggest that the exact shape and structure of each natural snow crystal is unique – so that means YES – no two snow flakes are identical.  Especially if you consider the different factors that are involved in creating each snowflake!  HOWEVER, for more simple snow crystal structures it can at times be hard to tell the difference between two under a microscope!

WHY IS SNOW WHITE?

When we observe the colour of an object we are actually seeing the colour of light that the object REFLECTS (bounces back)- so green grass, for example, is ABSORBING (taking in) all light expect green light, which it is reflecting.  When an object appears white that means it is actually absorbing very little light and reflecting most or all of the light falling on it.  This is the case with snow, it’s crystalline structure creates many reflective surfaces making the light that falls on it “bounce back” or be reflected.  You can read more about this here.

IS IT EVER TOO COLD TO SNOW?

The simple answer to this is NO, once there is enough water vapour around to make snow, and enough circulating air to transport it then snow can be made at very low temperatures!  However, as warmer air can hold more water vapour we tend to get most snowfall at temperatures around freezing point or a bit below.

MAKE YOUR OWN SNOW FLAKE…

Now that you understand all about snow, how it is made and the different shapes and patterns it can take, I thought it would be fun to end with an experiment you can try yourself at home.  These are worth the bit of time and effort (and waiting overnight) as the results are really great!  Let me know if you try it and how you get on!

Images:
Dendrite snowflake photo National Geographic – Kenneth Libbrecht
Images of Fernlike Snowflakes by Kenneth Libbrecht

Further information:
Snow crystals photo gallery 
Observe and photograph snow
Fun snow facts for kids
Met Eireann Primary School Resource
10 Science Facts About Snow