Can you suffocate in snow?

Can you suffocate in an avalanche?

It is true that you only suffocate in snow, you cannot drown as drowning is where your lungs fill with water, and snow would have to melt to be water no longer making it “snow”.

     

Suffocation in snow is a condition, known as Snow Immersion Asphyxiation (SIA) or Non-Avalanche Related Snow Immersion Death. Most snow related suffocations occur due to skiers falling in tree wells headfirst. (see below for diagram of tree well.) Deep snow accidents occur when a rider falls into an area of deep unconsolidated snow and they become immobilized. If the individual struggles in the snow they will either sink further or become more trapped as the snow solidifies like concrete around them. It is advised that “If you get sucked into a tree well or fall in deep snow attempt  to tuck, roll, and land upright, grab the tree trunk or a branch, and yell to alert your partner. If buried upside down, stay calm and create an air pocket, which could buy you some precious minutes of oxygen”.

See to the left the individual is 6ft tall however you can only just see their head out of the tree well.

The key to surviving SIA is by travelling with a buddy and carrying an avalanche beacon. If an individual does not travel with a buddy the chances of survival after entrapment become very slim. In some cases people can die due to snow suffocation as quickly as they can drown in water (usually as fast as 15 minutes). Most cases of SIA are recorded in December and January due to the weather conditions in this season. Many people concern themselves that they may become get hypothermia when trapped, however your body will not survive long enough to get this when submerged.

Asphyxia is a term referring to breathing insufficiency leading to inadequate intake of oxygen and inadequate exhalation of carbon dioxide. The suffocation begins as snow blocks your respiration, thus your heart will accelerate, trying to feed oxygen to your body. When your heart beat reaches 220 beats per minutes, the heart will stop working as a pump, therefore no blood can be carried. You will feel as if you're fainting as your brain gets no oxygen. Unless immediately defibrillated, your heart then stops working all together.

The odds of surviving a deep snow immersion accident are low; especially if you are not with a partner. In two experiments conducted in the U.S. and Canada in which volunteers were temporarily placed in a tree well, 90% could not rescue themselves.

% of Tree Wells & Deep Snow  involved in SIA cases

Posted by: Jess 

28.2.2012

Sources: 

http://howto.wired.com/wiki/Survive_Deep_Snow_Immersion

www.treewelldeepsnowsafety.com/tree_wells.php

www.treewelldeepsnowsafety.com/

www.safete.com/safetyarticles/parents/suffocation.htm

http://www.adventuremedicalkits.com/blog/2011/01/avoiding-snow-suffocation-hazards-at-the-ski-resort-and-in-the-backcountry/

http://sids-network.org/experts/carroll2.htm 

What are glaciers and how are they formed?

Glaciers are made up of layers of fallen snow that over many years has been compressed. This compression causes the snow to re-crystallises into granules similar to that of sugar. Over time the continued compression of the snow reducing the air pockets between them as the crystals become larger to form large ice masses. They currently occupy 10% of the earth’s land mass and are mainly found in Greenland and Antarctica.

These are a particularly interesting aspect of snow and ice as they have the ability to move. When ice is put under this large strain the ice will fracture. Water is a substance that under pressure lowers the temperature the solid to liquid transition takes place at, in this case sub-zero. This causes a lubricating film of water to form under the glacier, which along with gravity and the weight of the ice causes it to flow downhill. Movement along the underside of the glacier is slower than the top due to the friction made by the grounds surface.

Here is an experiment that could be used to demonstrate the flow of a glacier.

Flubber Experiment

Materials

·         Warm Water

·         White Glue(Elmers)

·         Borax

·         PVC pipe cut in half

·         Clingfilm

·         Cooking Oil

·         Sandpaper

·         Ruler

·         Freezer/ Microwave

Firstly create two mixtures the first consisting of a ¾ cup of warm water and 1 cup of glue. The second is made up of 2tbs of borax and ½ a cup of warm water. Next combine the two together and work through the hands until a consistent texture is reached.

 The children can then experiment with what can influence the speed / flow speed of the glacier. They could change the independent variable to; steepness of the slope, temperature of the flubber or even the conditions at the base of the flubber in order to experiment what the effects could be.

Glaciers often have rocks and debris underneath them which can restrict flow this could be demonstrated with the use of sandpaper which will significantly increase friction. Similarly some glaciers have a thin film of water underneath them. This can be modelled by smearing cooking oil over the PVC tube. By experimenting with all this different ideas the children can begin to grasp the idea of just how glaciers move in a fun and hands on way.

How far south did glaciers come?

Whilst glaciers in England only reached as far south as Oxfordshire around the world glaciers came so far south that they actually appeared in the tropics. The tropics are defined as 30ºN and 30ºS latitude. Some examples of glaciers in this area are Yanapaccha glacier, Peru and the Elena glacier near the Republic of Congo and Uganda border. However, as you can see from the pictures below they are rapidly depleting.

Elena Glacier 1906-1994

Could the South Downs have been affected by glaciation?

125 million years ago the south east was covered with fresh water lakes and rivers which carried clay building up layers at the base of the river. Soon after the sea began to break through laying down chalk made up of skeletons of dead sea creatures this created the bases of the South Downs.

The South Downs were originally formed by two tectonic plates (Eurasian and African plate) colliding the pressure at the point of impact caused the area to be upwards creating mountain chains. This is called alpine orogeny.

 Whilst no glaciers reached the South East the tundra like conditions which can be found on the edge of ice sheets dominated this area. As Carter states “Frozen chalk prevented further absorption.”(1990) this meant that the summer rain and melt water formed streams which carved out valleys. As the climate rose the water began to soak through the chalk which is an example of an aquifer which is a type of rock with small holes like pores which allow water to soak through leaving what is called dry valleys.

So in answer to the question posed whilst glaciers did not cause the formation of the South Downs . The freezing cold temperatures caused by the Ice age did however, aid the erosion process which shaped the already existing South Downs.

Resources I Used.

·         http://www.weatherquestions.com/What_causes_glaciers.htm

·         http://nsidc.org/cryosphere/glaciers/questions/what.html

·         http://www.realclimate.org/index.php/archives/2005/05/tropical-glacier-retreat/

·         http://www.southdowns.gov.uk/learning/themes-to-study/landscape/geology/geology-through-time

·         http://www.naturalengland.org.uk/ourwork/conservation/geodiversity/englands/counties/area_ID34.aspx

·         Timothy Carter (1990) Encyclopaedia of Brighton

What are lichens and how do they live?

Lichens are fungus and algae in a symbiotic relationship. The fungus is the visible part of the lichen, and it acts as a protector for the algae, enabling it to survive in harsh conditions that it would not be able to survive in alone. The algae contains chlorophyll, which enables it to photosynthesise, providing nutrients for the fungus. The same fungus can combine with different algae, and similarly the same algae can combine with different fungi, to make variations of lichens.

Lichens can live and grow almost anywhere, from rocks to trees to desert sand, and as they are often the first to inhabit hostile conditions, they provide the foundations for a lot of environments. To enable them to survive extremely difficult conditions, lichens are able to shut down metabolically but still survive until the conditions turn favourable again. Most lichens grow very slowly - only about a millimetre per year.

The explanation of why lichens would be found on one side of the log but not the other, is most likely because the side the lichens were not growing on was the side touching the ground, and the exposed side is a better environment for the lichens, with more space, air and sunlight.

Sources:

http://www.hiddenforest.co.nz/lichens/what.htm

http://www.countrysideinfo.co.uk/fungi/lichens.htm


(Zoe)

How does hibernation work? By Lauren Harden

How does hibernation work? What do insects do?

In autumn hibernating animals eat extra food while it is plentiful. This is stored as body fat in order to be used later for energy. Hibernators have two kinds of fat: regular white fat and a special brown fat. The brown fat forms patches near the animal's brain, heart and lungs. It sends a quick burst of energy to warm these organs first when it is time to wake up.
During hibernation the animal’s body temperature drops and their breathing and heart beat slow down significantly this reduces the energy consumption. For example, a hibernating woodchuck's heart rate slows from 80 to 4 beats per minute, and its temperature drops from 98 F to as low as 38 F. However if their body temperature drops too low the animal will wake up and shiver to raise their temperature.

How do animals know it is time to hibernate?

This is still being widely researched. It is believed that hibernating animals have something in their blood called HIT (Hibernation Inducement Trigger). Recent research suggests that it is some kind of opiate, chemically related to morphine. HIT is triggered as the days become shorter, the temperature changes, food becomes scarce and as a result hibernation occurs. How and why it happens are still a mystery.

Insects

Insects all behave slightly differently during winter, each adopting separate approaches to staying warm including:

Communal living

This is when insects find warmth in numbers. Honey bees group together for warmth and ants head deep underground with large food supplies where the stay sharing body heat throughout winter.

Torpor

This is a temporary state of sleep which keeps the insect still and unmoving in order to conserve heat and energy. Some insects do this at night and during the day come out of torpor to continue as normal.

Diapause

This is a long term state of suspension. This allows the insects life style to be in sync with the seasonal climate. If the conditions are too cold to find food or migrate the insect will pause during development.

Eggs of the praying mantis only emerge during the spring.

Larvae of caterpillars curl up in leaves and only spin their cocoons in the spring.

Pupa Black swallowtails spend winter as chrysalids, emerging as butterflies when warm weather returns.

Adult Mourning cloak butterflies hibernate as adults for the winter, tucking themselves behind loose bark or in tree cavities.

Antifreeze

Many insects are prepared for the cold weather because they produce their own antifreeze. During the autumn insects produce glycerol which gives the insect the ability to allow body fluids to drop below freezing points without causing ice damage. Glycerol also lowers the freezing point, making insects more cold-tolerant, and protects tissues and cells from damage during icy conditions in the environment. In spring, glycerol levels drop again.

http://www.sciencemadesimple.com/animals.html
http://insects.about.com/od/adaptations/p/wintersurvival.htm

What is an allergic reaction? And how might wood smoke cause it?

What is a an allergic reaction? And how might wood smoke cause it?

The term allergy is used to describe a response, within the body, to a substance, which is not normally harmful within itself. An allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when an allergen comes into contact with that come into contact with the skin, nose, eyes, respiratory tract, and gastrointestinal tract. They can be inhaled into the lungs, swallowed, or injected. An allergic reaction can affect a small area of the body or ma affect the entire body. The most severe form of allergic reaction is called anaphylaxis. Although first-time exposure may only produce a mild reaction, repeated exposures may lead to more serious reactions. Once a person has had an exposure or an allergic reaction (is sensitized), even a very limited exposure to a very small amount of allergen can trigger a severe reaction. An allergy is everything from a runny nose, itchy eyes and palate to skin rash. It aggravates the sense of smell, sight, tastes and touch causing irritation, extreme disability and sometimes fatality. It occurs when the body's immune system overreacts to normally harmless substances. Allergy is widespread and affects approximately one in four of the population in the UK at some time in their lives. Each year the numbers are increasing by 5% with as many as half of all those affected being children.

Wood smoke is made up of a complex mixture of gases (carbon monoxide, nitrogen dioxide and carbon dioxide, among others) this wood smoke causes an allergic reaction in around 2% of the population. People working in the wood industry have a predisposition to this kind of allergy.

A wood allergy is an adverse reaction by the immune system caused by chemicals called, quinones (a class of organic compounds that are formally "derived from aromatic compounds). Compounds from these chemicals then bind with skin proteins (also known as the immune system), upon contact the immune system produces antibodies called Immunoglobulin E or IgE. The symptoms of the reaction vary between patients but generally the allergic reaction to wood resembles contact dermatitis with blisters, swelling, redness and irritation. Allergic reactions from wood smoke occur due to the very small particles in the smoke and soot. There are over 100 different chemicals in wood smoke, many of which are harmful and potentially carcinogenic. 


The fine particulate matter in the wood smoke is the most dangerous component, the most harmful particulates being those that are 10 microns or less in diameter (a human hair is 70 microns in diameter). These particles can be inhaled deep into the alveoli (small air sacs) in the lungs where oxygen is supposed to enter the blood. Not only can wood smoke provoke an allergic reaction but it causes permanent lung damage, increases cardiovascular problems. It can also have profound effects on respiratory diseases like asthma, emphysema, and bronchitis, which sometimes results in premature deaths.

An allergic reaction to sawdust.
Jess (24/02/2012)

The Bronze Age

The Bronze Age (Hayley) 

The Bronze Age originally began in Europe but was brought over to Britain in 2,000 BCE. Bronze is created by smelting tin and copper ores which are readily found in Britain. 

The Bronze was originally believed to have been brought to Britain by the Beaker people from Switzerland, so called because of their bell shaped pottery drinking vestals. Evidence of this civilisation has also been found at Stone Henge. 

Bronze was gradually used to replace stone for tools and weaponry. To create these objects they first had to recover the ores this was cleverly done by lighting a fire against the rocks this was called fire setting. Once the rocks were heated sufficiently cold water was thrown on it which caused contraction and the rocks to crack.  Other tools were also found in the Welsh mines such as leg bones of cattle which were driven in using stone. Some of these mines went down to approximately 150ft however, most were open cast. The copper ores were then crushed washed and placed in a kiln that used charcoal to heat it. It was then mixed with tin and put in casts to cool and create the desired object.

As Coyle states tin is a scares metal and is only 0.001% of the earth’s crust. It was mainly found in the Southwest of England in areas such as Devon and Cornwall . From around 1600 BCE tin was mined in the Southwest of England which experienced a substantial boom period, as tin was traded readily to the whole of Europe in order to make bronze. Copper ores however was mainly found in Great Orm situated in North Wales, along with Cheshire and Isle of man.

It would not be practical for us to do this in the woods as in the downs there is not any copper ores in the soil as it is mainly consists of chalk and lower weald . It would also be impractical for us to get our hands on a kiln.


What are Ores?

An ore is any naturally-occurring source of a metal that you can economically extract the metal from. Ores can be extremely hard to extract as they can be found deep in the ground  and must be mined. To get a pure form of copper the best way to extract copper from the unwanted material is by using a chemical called sulphuric acid. To do this the ores must be crushed and left in dilute sulphuric acid. The copper can then be extracted. Another way to separate the two is by using froth flotation. In this method the ore is crushed and mixed with pine oil which binds to the copper compound but not the unwanted material. The treated solution is then put in a bath of water containing a soap where air is blown into it to create bubbles. The copper coated in the hydrophobic oil floats up to the top of the bath and can flow over the sides. This is an extremely advanced method and obviously would not have been around during the Bronze Age therefore their copper would not have been so refined.




The Smelting Process:

Smelting uses heat and a chemical reducing agent to reduce the ores, this leaves the metal behind. The high temperatures created within the clay kiln reached 1100 degrees which could only be achieved by using forced drafts as well as natural drafts.

Sources Used:

·         Geroff Coyle,(2010)The Riches Beneath Our Feet: How Mining Shaped Britain.Oxford Press

·         http://www.prehistoric.org.uk/bronze-age/

·         http://www.chemguide.co.uk/inorganic/extraction/introduction.html

·         http://www.derbyscc.org.uk/alderley/mining_process_1.php#3

The Various Types of Precipitation

What is the difference between the various types of precipitation? I.e. snow, sleet, freezing rain and rain

Precipitation can be divided into three types dependent on whether it falls as liquid water, liquid water that freezes on impact with the surface, or ice. Different types of precipitation can fall simultaneously. Rain is an example of liquid precipitation, freezing rain is an example of liquid that freezes on impact, and snow is an example of frozen precipitation.

Rain, and all precipitation, occurs when a portion of the atmosphere becomes saturated with water vapour (the ‘gas phase’ of water) and the water condenses. Two processes can lead to the air becoming saturated; cooling the air and adding water vapour to the air.

Freezing rain is where a droplet starts as snow, and melts as it falls through the layers of the atmosphere. This melted snowflake then hits a below freezing layer of the atmosphere near the Earth’s surface. This quickly cools the droplet, meaning that on impact with a surface it will freeze; turning into ice and coating what it hits with clear ice. The cold layer which the melted snowflake hits is thick enough to cool the drop below 0cº but not thick enough to freeze it to sleet.

Sleet is similar to freezing rain except that it freezes before it hits the Earth’s surface. A snowflake falls, enters a warm layer and melts. This melted snowflake then enters a cold layer near the surface of the Earth and freezes again. When this frozen droplet hits the Earth, it is usually in the form of ice and it does not freeze on impact.

Snow, on the other hand, can only form when the atmospheric temperature is below 0cº and won’t settle if the ground temperature is above 4cº. Snow will form when the atmospheric temperature is below 0cº and when there is a minimum amount of moisture in the air. Snow is basically made up of crystals of frozen water; ice crystals have 6 points, however one snowflake can consist of multiple crystals. Snow will reach the Earth’s surface so long as it does not pass through any layers in the atmosphere that are above freezing.

Emma Barkley, 14^th February 2012

Bibliography: (All accessed 14th February 2012)

http://nsidc.org/snow/faq.html

http://www.planetpals.com/weather.html

http://ezinearticles.com/?Snow,-Sleet,-and-Freezing-Rain---Theyre-All-the-Same,-Right?&id=868391

http://www.enotes.com/science/q-and-a/what-difference-between-freezing-rain-sleet-289352