A School …. in a Forest…and How to Stay Dry!

When young, we often form our own ideas about what the woods are like, whether they be full of fear while reading about Big bad Wolves that chase little children, candy houses that are homes to Witches and gigantic Spiders with thousands of eyes and big spindly legs. Or we see it as a place of adventure and wonder, home to merry men in tights, Fairies, Elves with pointy ears and Teddy Bears having picnics. In fact, throw together a few anthropomorphised creatures, hairy monsters, and a deep, dark, wood, and you have all the magical ingredients for a classic children’s story!. Nevertheless, whether as children we see the woods as big and scary, or full of wonder, what we can agree on is it is a magical place full of adventure. It was with this in my mind that I first entered Seeley Copse, “anything could happen here in the next few weeks” I thought to myself, but I decided right then to place one foot firmly in front of the other and to meet adventure head on, to take part, to have fun and to hopefully learn a little on the way!.

Some children’s stories are just plain scary! RUN RED RIDING HOOD!

Our group was led by our own Wild man/survival expert/lecturer Duncan, who would lead us safely along the way much like Gandalf leading the Hobbits on their way to reclaim their lost home from Smaug or Hagrid leading Harry, Ron and Draco through the forbidden forest.

The day was muddy, cold and yet amazing fun!. We made fires, used tools and led each other blind around the woods to see if we could navigate the terrain without being able to see! (surprisingly, no injuries!). We did however, all return to our cars muddy and extremely cold and this got me thinking about the importance of wearing the correct clothing and how it works!. So….

WHAT DO YOU NEED TO WEAR TO SURVIVE IN THE WOODS?

1. A good pair of walking boots or wellies! 

2. Waterproofs – A coat at least but trousers if you have them!

3. Something thermal! a top or trousers (I have a t-shirt and long Johns)

4. For especially cold days, a good pair of gloves and a hat is also essential

All of these items are pretty essential if you want to remain comfortable while it’s cold and/or wet in the woods, but how does something like waterproofing work?.

Waterproof Clothing

Sporting a very fetching waterproof outfit there!

A brief history:

Synthetic waterproof/breathable clothing has been around since 1978 when it was introduced by a popular brand called “Gore-Tex”. Gore-Tex was special as they were the first to introduce clothes that not only kept the rain off but that were also breathable. This meant that when you got hot and sweaty inside your  coat, you wouldn’t stew in it because the coat would let the particles of sweat out!

Since then, many companies and brands have also started producing waterproof/breathable items of clothing and footwear, most people still refer to these items as “Gore-Tex”. However! Not all waterproof / breathable items of clothing are Gore-Tex – just like not all cars are Ferraris and not all coffee is from Costa.

So what’s the Science? how does it work?

Breathable water proof clothing performs two tasks when we wear it:

1. Withstands moisture (keeps us dry)

2. provides an escape for perspiration vapours (remains breathable allowing sweat to escape).

Breathable clothing makes sure this doesn’t happen!

The clothing is able to do this by being made up of usually 3 layers (see image below)

waterproof breathable fabrics

These layers each perform their own job in any piece of waterproof/breathable clothing that you are wearing.

1. The outer or “Face Fabric” layer – This layer is usually made up of Nylon or Polyester, it repels water, protects the clothing and other layers and also is the part that “looks good”. This layer although able to repel water is not waterproof, it is usually treated with a “Durable Water Repellent” which causes water to “bead”(see image below).

Water Beading

2. The membrane layer – This layer is made of Teflon or of Polyurethane. the membrane helps to repel water from the outside but also allows water vapour (from your smelly sweat glands Ewww) to escape. This is possible through microscopic holes (or pores) that are small enough to stop any water molecules getting in from outside but large enough that the smaller molecules of perspiration can pass through. See below for a visual representation of this!

This shows the membrane repelling incoming water molecules but allowing moisture vapour from your body to pass through.

3. The tri-coat mesh – This layer creates extra comfort to the wearer and also provides protection to the membrane layer.

The grey mesh layer can be seen in this picture

You may well now be saying, “this is all very well but how do I know what the best waterproofs to buy are and what are these numbers on the labels!”. Well the numbers on the labels tell us how waterproof (or how good at its job) the waterproof clothing is. The higher the number the better the job it will do!

Manufacturers of the waterproofs we buy use numbers and units to let us know how good a piece of clothing is at resisting water.To indicate this waterproof rating, they use millimetres. If for instance we take a coat that says it has a rating of 10,000 mm then that means that if you put a square tube which has inside dimensions of 1” x 1” over a piece of clothing, then you could fill it with water to a height of about 20,000 mm (65.6 feet) before water would begin to leak through.The higher this rating is the more the coat can withstand! Below is a table that shows an example of this.

Waterproof Rating (mm) Protection Provided What it’s Good For
0 – 5,000 mm No protection to some protection to moisture Light rain, dry snow, no pressure
6,000 – 10,000 mm Rainproof and waterproof under light pressure Light rain, average snow, light pressure
11,000 – 15,000 mm Rainproof and waterproof except under high pressure Moderate rain, average snow, light pressure
16,000 – 20,000 mm Rainproof and waterproof under high pressure Heavy rain, wet snow, some pressure
20,000mm + Rainproof and waterproof under very high pressure Heavy rain, wet snow, high pressure

 

Bears Quote of The Day:

Being brave isn’t the absence of fear. Being brave is having that fear but finding a way through it. – Bear Grylls

References:

http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway/carbon_chemistry/designer_polymersrev2.shtml

http://nwt3k.com/blog/waterproof-jackets-and-fabrics-guide/

http://www.mensfitness.com/life/gearandtech/how-it-works-a-waterproof-jacket

http://www.evo.com/waterproof-ratings-and-breathability-guide.aspx

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