Wood burning- Victoria Oakey

Different types of logs

Why do different types of logs burn differently?

Hardwoods are generally better for burning than softwoods. Hardwoods are produced by slow-growing deciduous trees therefore the logs have a greater density than the faster growing softwoods from evergreen trees. Since hardwood logs are heavier than the same sized softwood log they will provide you with much more heat output – up to 50%.

 

However, an argument suggests that the type of log isn’t important it is how long that the wood has been seasoned for. Some wood especially hardwood needs to be seasoned for over a year e.g. oak. Wood seasoning refers to the drying out of wood in preparation for burning. Wood needs to be free from moisture in order to perform. Burning damp or green wood causes loss of energy due to evaporation. If a 50% wet log is burnt at high temperature, with good heat extraction from the exhaust gas leading to a 100°C exhaust temperature, about 5% of the energy of the log is wasted through evaporating and heating the water vapour. Burning green wood is not as efficient as seasoned wood, it can cause a lot of smoke and it is a large waste of energy. Oak is an example of an effective hardwood and needs to be seasoned for over a year in order to get the maximum potential from the wood.
When we created fire at the fire circle in Seeley Copse, it did not matter whether we were using seasoned or green wood as we were using wood taken from the environment for a simple purpose to keep us warm therefore it was not an important factor. However some people still live in houses relying on an open fire or a log burner. Firewood can be very expensive so people who live in these houses do not want to be wasting g money by burning green wood therefore it is essential that they understand how long their wood should be seasoned for in order to get the maximum heat and usage out of the wood.

Victoria Oakey
Bibliography
http://www.thestoveyard.com/pwpcontrol.php?pwpID=7115
http://www.mastersweep.com/wood.htm
image- http://www.frenchentree.com/fe-lavie/DisplayArticle.asp?ID=19397

Lichens

Lichens are organisms consisting of a fungus (the mycobiont) and a photosynthetic partner (the photobiont or phycobiont) growing together in a symbiotic relationship. The morphology, physiology and biochemistry of lichens are very different from those of the isolated fungus and alga. Lichens occur in some of the most unusual and exotic areas on earth—such as deserts and arctic tundra. However, they are also abundant as they grow on leaves and branches in rain forests and temperate woodland, on bare rock, including walls and gravestones, and on exposed soil surfaces. Lichens can often be seen growing on the roofs of houses too. Lichens are widespread and may be long-lived; however, many are also vulnerable to environmental disturbance, and may be useful to scientists in assessing the effects of air pollution.

Lichens and air pollution

Lichens are exposed to air pollutants at all times, without any deciduous parts, they are unable to avoid the accumulation of pollutants. Also lacking stomata and a cuticle, lichens may absorb aerosols and gases over the entire the surface. Because lichens do not possess roots, their primary source of most elements is the air, and therefore elemental levels in lichens often reflect the accumulated composition of ambient air. Many environmental studies with lichens emphasize their feasibility as effective bio monitors of atmospheric quality.
Not all lichens are as sensitive to air pollutants, so different lichen species show different levels of sensitivity to specific atmospheric pollutants. The sensitivity of a lichen to air pollution is directly related to the energy needs of the mycobiont, so that the stronger the dependency of the mycobiont on the photobiont, the more sensitive the lichen is to air pollution.

Victoria Oakey

Investigating soil pH around the fire circle- Victoria Oakey

My investigation

 

Following our module in the woods Seeley Copse we had to create our own investigations. I and my partner decided it would be a good idea to look at the effects of the fire circle on the soil around. We decide to take a sample at the middle of the fire circle then every 20cm towards the edge of the fire circle. We used a sol testing kit which allowed us to indicate the pH of the sample.

 

 

 

Our results gave us some very interesting results. My partner and I collected a total of 8 samples and it was clear to see that the pH of the samples became more neutral the further away from the fire circle. The first sample we collected was a rich navy colour indicating a strong alkaline sample however sample 8 was a pale green colour however it was not close enough to pH 7 to be neutral, it was still an alkaline however it was a lot weaker than the sample taken at the centre of the fire circle.

Next time we would carry out an investigation I feel that it would be really important to look at the effects on the depth of soil too.

Victoria Oakey

 

Bibliography

 

Image- http://mountliming.co.uk/soil-analysis/buy-a-soil-testing-kit/

FIRE!

The science of fire- Victoria Oakey

Fire is caused by a chemical reaction of 3 main elements. These elements are oxygen, fuel and heat. The fire triangle is a well-known way of remembering the elements needed to create fire.

 

We must make a point that wood and petrol do not spontaneously catch on fire because they are surrounded by oxygen, for combustion reaction to happen, you have to heat the fuel to the ignition temperature.

The sequence to cause fire is…….

Something heats the fuel; to a high temperature, this can come from many different sources for example a match, lightening or friction and possibly something already on fire.  When the wood heats up to roughly 150 degrees Celsius, the heat removes some of the cellulose in the wood. Cellulose is the material inside wood.  Some of the decomposed material, caused by this reaction, is released as various gases. These gases are known as the ‘smoke’ of a fire. Smoke is made up of compounds of hydrogen, carbon and oxygen. The left over material forms char. Char is nearly 100% pure carbon and is made up of the unburnable minerals in the wood.

Fire is a beautiful phenomenon however it is also very dangerous. Fire is self-perpetuating. The heat of the flame itself keeps the fuel at the ignition temperature, so it continues to burn as long as there is fuel and oxygen around it. The flame heats any surrounding fuel so it releases gases as well. When the flame ignites the gases, the fire spreads.

 

Bibliography

http://en.wikipedia.org/wiki/Fire_triangle – Fire triangle picture

How fire works? – http://science.howstuffworks.com/environmental/earth/geophysics/fire2.htm

Cross section of tree – Gemma

Cross section of wood – Gemma

 

From looking at my cross section of wood it was not easy to see how many rings there were, it was obvious to see that there were a few dominant rings that do occur though. There are about 3 dominant rings and by looking closely there were around 18 other rings, meaning this tree would have been about 21 years old. It is hard to tell the age from this cross section as the rings do not tend to form a full circle around the centre point also known as the pith. This is the clear centre circle that can be seen in the photo. It is off centre, only completed three quarters of the circle and is not a very circular shape. But in other tree cross sections you would get a circular and central shape. The reason my cross section is not in the centre is due to the fact that it would have been growing towards the sunlight so was leaning towards that side. This cross section is a good example of seeing the vertical lines that happen in wood, these are vital as they are the production and deposit of the nutrients and moisture to the tree.

The cross sections shows a number of different shades throughout it all. The lighter shades would occur from the spring as it is growing at a constant ace over a long period of time. But the darker parts that can be seen would be where the growth was at its faster, usually through the summer months as the growth is it its maximum due to the hotter weather. Some of these darker patches would also be where there are dead cells within the tree. This would be when the tree was growing and these cells were near the bark and got damaged in some way, then they were unable to get the nutrients needed and later died because of this. This cross section shows a number of darker patches on it, meaning that it may well be older than it looks to be, it was just a very damaged tree as it was growing. The tree was also on the ground when the cross section was cut so it is hard to say how long it had been on the floor for, so the wood would have already began to break up and die as the nutrients would not be going around the tree.

Lichens – Gemma

Lichens – Gemma

 

 

 

What are lichens?

 

There are over 30,000 species of lichens dotted around the world. Each and every one varies in size, colour and shape. They are made up two things, one is a fungus and the other is alga, mixing together to create a lichen. These lichens can be both invisible and visible to the naked eye, and at the moment they are covering up to 10% of the land in the world as they are able to grow just about anywhere. One of the best places in which these grow is on the logs and branches from trees.

 

Why do lichens grow on logs?

 

There are a few reasons why the growth of lichens is good on trees and their logs. One of these is the fact that they are able to help the logs to decay. One particular lichen that is well known is the British soldier, this is able to break up the wood at the same time replenish the nutrients in the soil ready for other plants and animals to be able to use. One of the other reasons is that the lichens are not in any competition by growing on the logs. There is no block occurring from the leaves, meaning that they are able to get a good amount of sunlight o aid their growth and then help the log to decay. These lichens also photosynthesise, they are getting some moisture from the logs and the sunlight beaming in on the logs creating very good photosynthesising conditions for them. This is why they is such a large spread of them throughout the world.

 

What are the uses of these lichens?

 

A good use for the wildlife is the fact that they are able to recycle nutrients from other plants, aiding the habitat building of insects and spiders especially. This is also useful as they are able to live along side plants and animals so they are just mixed in with the environment, you don’t get patches where only they grow and other patches where there are animals and plants. A use of them will also link back to the dye of wools and materials, a huge range of these lichens have been used to dye natural materials and their colour is easily absorbed. But the lichens also help humans, they can be used in sunscreen as they produce a natural block to the sun’s rays and are also commonly found in antibiotics as they produce chemical compounds.

 

Lichens are also a good measure of air pollution. If there is a high amount of air pollution then there is likely to be less lichens around as they do not act well to air pollution. But there are some lichens that thrive off of nitrogen, but nitrogen is seen to be a pollutant. This also has its positives as the high levels of nitrogen are able to be monitored if a large spread of these lichens are found in one particular place.

 

 

http://www.hastingsreserve.org/oakstory

Fixing of dyes – Gemma

The fixing of dyes – Gemma

 

All kinds of materials can be dyed  using various naturally occurring objects. This method of dying has been traced back to around four and a half thousand years ago, and began to take place in Ancient China. But, more recently the natural dyes were being used by the Germans in World War II, where they found things like nettles worked to dye the clothes, and gave their uniforms a distinctive colour to avoid confusion.

But how are these colours fixed to the material? Something known as a mordant is used. A way to describe these mordant’s would be that it bites into the fabric, giving the available dye something to fix onto. The word mordant came about as in French it means to bite or to cut. A mordant is not always necessary as some dyes are strong enough to fix themselves to the materials without the aid of a mordant. A mordant can be made from many different things, but a lot of people tend to use vinegar, salt solution and the least common alum. There are many more solutions that are available, but people know that they can use these and rarely have an allergy to them. Alum is the shortened name for something called Aluminium potassium sulphate. The material will be soaked for a number of hours in a chosen mordant, after this the rest of the process is ready to begin. It forms a chemical link that is able to fix the dye to a substrate by combining with the pigment from the dye to form an insoluble compound. All dyes fit into two categories. The first being adjective and the second being  substantive. The dyes that fit into this adjective category tend to need the mordant to fix the dye, and most naturally occurring objects will fit into this objective category.

What do the different mordant’s do and what effects do they have on the material? Every mordant goes through the same process to allow the fixing of the dye to the material. But dependent on the intensity of the mordant depends on the amount of colour absorbed by the material. For example, the Alum mordant will take on more colour to the fabric than a salt solution would, meaning the different shades of each colour would occur.

 

http://www.earthues.com/aboutmordants.html

http://www.theecologist.org/green_green_living/clothing/404783/how_to_dye_clothes_using_natural_methods.html

Chalk – Gemma

 

Chalk is made from something called calcium carbonate (CaCO₃), this is a mixture of calcium and carbon. This is formed from fossil microorganisms, also known as the skeletons of small animals. But, chalk can also refer to and be made up of other compounds including such things as; magnesium silicate and calcium sulphate. It is a pourus, sedimentary rock and a form of limestone composed of mineral calcite which forms under a number of deep marine conditions.

 

The accumulation of chalk sheds from microorganisms called coccolithophores, where it is also common to find chert or flint embedded in chalk. The latin word for chalk is ‘calx’. The chalk that is found in all of these cliffs and hills has been built up for a long, long time. Sometimes it could have been for up to one hundred million years ago. There is a vast variation in colours of chalk that can be found. The types of colours that can be found include grey, yellow and white, but there are a number of different shades of each of these. These occur due to the different impurities found within the chalks. Interestingly, when the chalk is under a large amount of heat and pressure it changes to marble, so this is also found deep in the cliffs and hills, and will have taken a similar amount of time as the chalk would have done.

 

But what are the uses of this chalk?

 

They are used widely in schools, not so much now as they were many years ago, but this is due to the adaptations with technology. Another common use for the chalk is the marking out of sports courts, this includes courts like tennis and football pitches. There are some other less obvious uses of the chalk, like in toothpaste, and the removal of perspiration. But artists also have a common interest for chalk, not only do they use it to do art work on things like the pavements, they also use it to mark out designs on fabrics in textiles, aiding them with the sewing. So, the finding of chalk has helped many people in different way.

 

∞

Stinging nettles – male and female plants – katie

female flowers of a stinging nettle plant
(google images)

Difference between them

Unlike many plants, stinging nettles have separate male and female plants. Female plants grow in more dense clusters than male plants. The male flower part of the plant contains stamens only. These produce pollen and are what fertilize the eggs in the female plant. The female plant contains a pistil that has a single egg and produces a single seed. The female plants also have a wider array of flowers compared to the male plants and the flowers face downwards where as the flowers on a male plant face upwards at an angle.

How the plant is pollinated

When the plant is mature, the pollen is caught by the wind and blown along. When the pollen is blown to a female plant, the stigma of this plant catches the grain and it is travelled to the ovary. This will then grow into a small fruit which contains the only seed produced by the flower of the plant. The male and female plants each contain one set of chromosomes and when these meet they create a zygote. The zygote then undergoes mitosis (asexual reproduction.)

 

 

http://www.ehow.com/facts_6183284_difference-_amp_-female-nettle-plants.html

http://bioweb.uwlax.edu/bio203/2011/homolka_kail/reproduction.htm

http://www.uksafari.com/stingingnettles.htm

http://www.herbs2000.com/herbs/herbs_nettle.htm

 

 

Why animals Hibernate – Liv

The most common definition of hibernation is a long-term state in which body temperature is significantly decreased, metabolism slows drastically and the animal enters a coma like condition that takes some time to recover from. All living animals are constantly burning energy, through exercise, heat, digestion, breathing and pumping blood. Even while sleeping energy is burned. Therefore, during the winter, when food reserves are low, animals have to either find other food sources or find ways of preserving energy. In order to find other food sources, some animals will adapt their diet and others will migrate to areas that still have their food source available. However, for smaller animals that cannot migrate easily, other methods must be used. The main way for animals to preserve energy is to hibernate. While hibernating the animal will lower its body temperature, sometimes to below freezing and lower its breathing and heart rate. This is what causes hibernation to be different from sleeping as when sleeping, animals undergo a change psychologically, while when hibernating, animals experience a change physiologically.

The link below shows the extraordinary struggle one animal has to go through to survive the winter.

http://www.bbc.co.uk/programmes/p00l72dn

Hibernation is mainly controlled by the endocrine system. Glands in the body alter the amounts of hormones being released and can control just about every physiological aspect of hibernation.

• Thyroid – gland that controls metabolism and activity levels
• Melatonin – hormone that controls the growth of winter coats
• Pituitary – gland that controls fat buildup, heart rate and breathing rate, as well as metabolic functions
• Insulin – hormone that regulates the amount of glucose (sugar) needed by the animal

http://science.howstuffworks.com/zoology/all-about-animals/hibernation.htm