Surfactant Chemicals

Name often given to detergents as it is the main ingredient in cleaning products. Synthetic chemicals which helps make water ‘wetter’ thereby enabling it to wet a dirty surface and lift

dirt from it. They have a hydrophilic and hydrophobic end.Degreasers

Dissolves oils, fats and greases which are not soluble in water.

Contains non-polar solvents hence is able to clean oil and grease off machinery.Lubricants

Reduces friction and wear between moving surfaces Usually oil-based and are used in engines and other machines were moving parts rub together Can be liquid (oil) or solid (grease)

Pesticides Materials which are able to selectively kill an animal considered to be a nuisance

Solvents Liquids which can dissolve another substance. Two main solvents are water and alcohol; also; turpentine.

Solute - The substance which is dissolved in a solventSolution The resulting mixture when a solute dissolves into the solvent The solvent molecules surround the solute molecules, preventing them from re-joining

Solubility Ability to dissolve in water - Ionic (where a positive and negative ions are bonded) and polar substances

dissolve in polar solvents; water and alcohol Non polar substances dissolve in non-polar substances such as turps, petrol, hexane and carbon

tetrachlorideSolution Contains at least one solute dissolved in a solvent, therefore it is homogenous. You cannot see the individual substances because it is uniform throughout When shining a beam of light through the solution, light is not scattered as there are no particles for the

light to be reflected off. Examples of solutions include vinegar (acetic acid in water), saltwater, household ammonia (ammonia

gas in water), shampoo and soft drinks There are two types of solutions

Solid dissolved in a liquid: saltwater Gas dissolved in a liquid: oxygen in water

Colloid Has ‘cloudy’ appearance; particles remaining suspended for long periods of time heterogeneous mixture The particles of one substance are scattered evenly throughout another Particles are smaller than the ones in suspensions, unable to be filtered out. Particles so small they

cannot be seen by the naked eye.Suspensions Contains large particles which are not dissolved in a solvent but mix uniformly together if the product is

shaken therefore heterogeneous Over time, if the mixture is left to stand, suspensions settle out or form layers The particles are large enough to be filtered out and to be seen by the naked eye The forces of attraction between the solvent particles and the large particles is not strong and over time

they are pulled downwards by gravity A beam of light can shine and is scattered due to the many particles which the light is reflected off Examples include dirt in water and others include

Solid particles suspended in a liquid: soluble aspirin Liquid particles suspended in a liquid: fresh milk

Emulsions Mixture of two substances that don’t normally mix well, such as water and grease Two types of emulsions

Oil in water: when the oil molecules disperse in water Water in oil: when the water disperses in the oil

The forces are continually braking and reforming and ‘holds’ molecules in liquid state. There are also forces that attract particles of one substance to particles of other substances. These are

called adhesion forces. Water has a high degree of surface tension which is why pond skaters and many other insects can run

about on water without sinking.

Surfactants

Cleaning products rely on surfactants to make oil dissolve in water.

Molecules of surfactants have both polar and non-polar pasts. The non-polar end wants to ‘get out’ of the water which is why surfactant molecules tend to pack together and lie across the oil-water interface

The non-polar end ‘hydrophobic’ molecule dissolves easily in the oil while the polar ‘hydrophilic’ end dissolves easily in the water. This is how surfactants lower the surface tension of water and makes it ‘spread out’ and make more contact with the dirt particles – Making it ‘wetter’

The tails of surfactants make contact with greasy dirt particles, while the heads form a layer around the dirt and draw water onto the fabric fibres and the dirt particles. The dirt can be separated from the surface with the help of agitation and heat. The solution containing the dirt/surfactant complex is then washed away.

Emulsion: Possibly the most important industrial role for surfactants is the formation of emulsions. An emulsion is a dispersion of one liquid in a second, immiscible liquid.

Emulsions are multiphase systems, continuous phase and the disperse phase. Allows oily material and water to be applied at the same time. Two liquids that do not normally mix are called phases To make two phases mix we need an emulsifier or emulsifying agent to reduce the difference in surface

tension; examples include cosmetics, foods, lubricants, medicines and paints. Emulsions are not permanently stable. In many emulsions, the liquids will separate after a certain time.

The finer the particle size, the more stable and the more viscous the emulsion is. For example: milk is an emulsion of butterfat (oil) in water. The emulsifying agent that enables the

butterfat and water to mix together is a protein called casein.

-Soaps and detergents are emulsifying agents because they assist two immiscible substances, such as oil and water, to mix. Soaps and detergents allow oil to disperse in water. -Soaps and detergents are surfactants because they act at the surfaces between two immiscible substances, such as oil and water. Detergents-Surfactants prepared from sulfuric acid and petro chemicals. Also called soap-less detergents-Are more versatile cleaning products because they can be adapted to perform well under a variety of conditions, are less affected by water hardness (therefore lathering more easily) and doesn’t form scumsSoaps-Also called soapy detergent-Good cleaning agent but soap molecules are not very versatile and cannot be adapted to today’s range of fibers, washing temp and water conditions.-Effectiveness of soap is reduced in hard water – water which contains a high level of calcium and magnesium salts. Hard water and soap produces insoluble soap scum and make the soap difficult to lather. Cleaning agents must be surfactants because they interact at the interface between two immiscible substances, creating an emulsion.

Cleaning agents must be emulsifiers because they maintain the emulsion. They act as emulsifying agents by causing the drops of oil to break up and remain suspended in the water. This means that the grease or oil can be washed or rinsed away with the water that is holding them.

To be effective as cleaning agents, soap and detergents must be effective both as surfactants and emulsifiers. Not all emulsifiers are good cleaning agents, for example egg yolk provides the emulsifying agent for the oil and vinegar to make mayonnaise.

Two important properties of surfactants:Adsorption

The taking up of a gas or liquid at the surface of another substance, usually a solid (for example, activated charcoal adsorbs gases). It involves molecular attraction at the surface. The adsorption properties of surfactants mean that surfactant molecules are usually found at the interface between an oil phase and a water phase or a water phase and an air phase. This molecular property leads to the macroscopic properties of wetting, foaming, detergency and emulsion formation.

Self-Assembly

Self-assembly is the tendency for surfactant molecules to organize themselves into extended structures in water. This includes the formation of micelles, bilayers and liquid crystals. These structures are formed by when the hydrophobic tails of the surfactants cluster together, forming small aggregates such as micelles, or large layer structures (bilayers) which are similar to a cell wall. These properties make surfactants very interesting study, and are areas of current research.

Biodegradability; term used to describe how micro-organisms such as bacteria act to decompose carbon compounds.

Biodegradable products are less harmful to the environment than non-biodegradable ones because they do not accumulate in the environment

Soap biodegrades very rapidly and takes only a few days for the micro-organisms to do their work. This is because, the bacteria used in sewage treatment plants digest unbranched linear chain molecules, such as those in soap. Soap is commonly the sodium or potassium salt of a natural long chain fatty acid.

The Skin

The skin is an organ to separate the body from the external environment. The epidermis forms an effective barrier to separate the rest of the body from the external environment. The stratum corneum consists of the dead skin cells that have died from lack of food and oxygen. These dead cells are firmly attached to one another. They protect the living cells beneath them and help reduce water loss. The dead cells flake away; form most of the dust that collects in our houses.

The skin is an organ assisting body temperature control. Sweat glands, found in the dermis, produce a liquid that is released through the pores in the epidermis. When this liquid is released on the surface of the body it evaporates and this in turn cools the body surface. When the body becomes hot, the rate at which these glands produce sweat or perspiration increases. As well as this, when the body becomes hot, the blood vessels dilate and fills with blood which allows loss of heat through the epidermis. These processes help to maintain the body temperature at 37oC.

The skin is an organ to protect against entry by disease-causing organisms.

The skin protects our body against disease in a number of ways:

Shedding of top layer of skin (the stratum corneum) helps prevent entry of disease causing organisms. The film on the surface of our skin, that contains a mixture of sweat, sebum and microflora, is acidic.

The acidity comes from the fatty acids that are present in the sebum and from the acids present in sweat. The acidity is increased by the presence of Staphylococcus epidermis, bacterial microflora that break down fatty acids in the sebum. Many other bacteria cannot survive in such acidic environment.

The high concentration of salt in sweat creates an environment that is inhospitable to many bacteria. The presence of skin microflora holds in check the small number of pathogenic organisms that are on

our skin surfaces. Different parts of the body have different populations of microflora, in balance with the small number of pathogens. This balance can be disturbed by variations in the diet, the use of antibiotics, the use of personal hygiene products and by physical injury.

Different parts of the skin

Epidermis

Layer of growing cells that lies at the bottom. It continuously moves upwards to replace those above. Most cell division takes place at night.

Contains the pigment-producing cells which give the skin its colour

Stratum Corneum

Barrier where the dead cells lie, flat and firmly attached to each other. Protects the underlying cells and acts to prevent water loss from the body.

Dermis

Contains the sensory nerves, hair follicles, sweat and oil glands and blood vessels. Has plentiful supply of blood vessels which keep the tissues alive but also assist in the regulation of body temperature.

Hair follicle

Each one in the skin grows one hair. Contains several sebaceous glands which excrete an oily substance called sebum which controls the oiliness of the skin.

Sebum mixes with sweat and forms a film over the skin near each hair follicle which slows moisture loss from the keratin and keeps foreign material out of the follicle.

At the base of the follicle is a muscle which contracts with cold or fright causing the hairs to rise and ‘goose pimples’ to form.

Sweat Glands

Made up of a tube which coils at one end, then becomes a duct leading to the surface of the skin where it opens as a pore. The coiled base is surrounded by blood vessels which bring the water, urea, and minerals to the sweat gland where they mix together and move up the duct. 99% is water.

Glands on our palms and soles react only to fright, pain or stress and begin producing sweat shortly after adrenaline is released into the blood.

Glands in the armpits, groin and around the nipples are called apocrine glands which excrete milky substance into the hair follicles.

Microflora are microorganisms, including bacteria, fungi, algae, protozoa and viruses that live in harmless association with our skin. They are able to survive the acidic nature of our skin and sometimes actually help us against the entry of pathogens. Microorganisms that cause disease are referred to as pathogens. The microflora also increases the acidic nature of the skin therefore making it even more inhospitable to many pathogens.

The number and type of microflora found on the skin varies in different parts of the body and between different individuals.

If the epidermis is unbroken, it provides an effective barrier against microflora. The surface of the skin is an inhospitable place as it is salty, acidic and the surface constantly breaks away to float off into the air. Drier parts of the body such as the scalp support fewer micro-organisms but moist areas such as the armpit support a larger population.

The highest populations of microflora are found on the surface in the stratum Corneum and below the surface in the hair follicles.

Skin in the linings of body cavities, such as the mouth, nasal passages, lungs and urinary, genital and gastrointestinal tracts have specialised ways to control microflora populations. Mucous membranes are often acidic, tears contain an enzyme which destroys the cell walls of certain bacteria.

Once a resident population of microflora built up on skin, it makes it harder for pathogens to survive.

Two main families of bacteria live on the skin

Small spherical cocci which depend on oxygen are harmless on the surface of the skin but Staphylococcus can cause serious disease if they enter bloodstream via broken skin or by medical procedures.

One species of micro flora, Corynebacterium acnes, live in the hair follicles, usually without harm to a person. However, when the dead skin from the epidermis occasionally blocks a sebaceous gland of a hair follicle, the bacteria may infect surrounding tissue resulting in inflammation and causing a pimple.

Role of microflora on different parts of the body

Although the skin is generally an inhospitable place for most micro-organisms, some microbes are established as part of the normal flora. Some aerobic bacteria produce fatty acids from sebum.

Microflora that can withstand dry, acidic and salt conditions can thrive on the skin. Washing the skin can reduce the numbers of microflora on the skin but those remaining in hair follicles and sweat glands will soon re-establish normal populations.

The pH scale can be used very effectively to describe the degree of acidity of a substance. The pH scale commonly has the range of 0-14. Indicators such as litmus paper, universal indicator paper or universal indicator solution, can be used to determine the pH of a substance. Alternatively pH meters or probes can be used to determine the pH electronically.

The natural oil in the skin; Sebum is produced by sebaceous glands and is slightly acidic.

The sweat or perspiration on our skin is produced by the sweat glands and is also slightly acidic. The composition of sweat varies according to the stimulus that produced its secretion. Sweat produced by heat is more acidic than sweat in response to exercise. A ‘cold-sweat’ that is secreted in response to intense excitement or fear has a more acidic ph.

Most bacteria can survive in a narrow pH range. The bacterial microflora on our skin are able to survive acidic conditions with a pH range 4-6. Other harmful bacteria cannot usually survive this environment and so our acidic skin protects us from harmful bacteria or pathogens. Some of our microflora are able to breakdown the fatty acid molecules (from the natural oils) in our skin and thereby increase its acidity.

The common components of most skin soaps, cleansers, shampoos are surfactants, oils, and fragrances and dyes. The pH of these products should be compatible with that of the skin.

Skin Soaps coats the skin grease-removing chemicals. Soap cleans because it consists of a hydro-carbon chain which is repelled by water but attracted to oil, grease and dirt, and a carboxylic (fatty) acid which is attracted to water. Skin soaps also contain coloring and perfume. They do not react badly when in contact with skin.

Cleansers are emulsions of oil-in-water designed to remove surface dirt and oil from the skin. The oils in cleansers absorb the oil and grease on our skin. Common components include mineral oil, water and a stearate and a moisture absorber. Cleansers dissolve sebum and loosen particles of grime and dirt.

Shampoos are pH adjusted to be neutral and most conditioners also mimic the action of sebum by smoothing the surface of the cuticle. The formulations of shampoos usually contain ingredients such as detergent to clean the hair, oils to coat the hair and prevent it from drying out, germicides to kill the bacteria which causes dandruff and coloring thickening agents and perfume.

The surfactants are needed to assist water to attach to oil particles, including sebum that is produced by sweat glands. The surfactant allows water to carry oil and dirt away from the skin surface.

Oils are included to replace the natural skin oil that is removed by the surfactant in the product. The oils can also protect skin surface or hair from drying.

Because these products are for use on the skin, the pH of the products must be compatible with that of the skin, which lies in the range 4-6.

Water and alcohol (ethanol) are commonly used solvents, particularly for use in products that are applied to the skin of or ingested by people.

Many carbon based solvents are usually referred to as ‘organic’ solvents, an example is ethanol (alcohol), turpentine and kerosene.

Water and alcohol are

common choices for use in cosmetics as they are both polar substances and dissolve a wide range of substances. Both are neutral and so will not affect the pH of the mixture and both are safe to apply to the skin.

Water is used as a solvent for facial cleaners, hair shampoo, conditioners, moisturizers, some creams (oil-in-water emulsions) and some emulsions like calamine lotion. Antiseptic solutions (e.g. Dettol) are dissolved in water before being used to bathe wounds. Water is used in substances which need to flow.

Alcohol is a drug and poison but in small doses, it can be safely used as a solvent. It evaporates at a lower temperature than water, so it gives a cooling effect when used on the skin. Alcohol dissolves fat, and therefore can dry the hair and skin when some products are used in excess. Alcohol is used as a solvent for astringents such as facial toner and aftershave, some antiseptics, perfumes, hair sprays and hair revitalizes and personal insect repellents. Iodine is dissolved in alcohol for use as a common antiseptic called tincture of iodine. Alcohol is also used in spray on pain killers.

Alcohol is a solvent that is used in preparing some cosmetics and external preparations because it has the capacity to dissolve some organic substances. It can do this because one end of the alcohol molecule is non-polar.

Some products such as antiseptic solutions use alcohol as a solvent because of its ability to dissolve some components that will not dissolve in water.

Some cosmetics and external preparations use alcohol because it evaporates quickly when applied to the skin or hair. Hairspray is a good example.

MOUTH p.H 6-8 Tongue and teeth do physical break up of food. Saliva: amylase (enzyme) breaks down starch

EPIGLOTTIS Flap of skin that closes over the trachea when you swallow, i.e. prevents choking.

OESOPHAGUS Food pipe. Peristalsis muscular movement which pushes the food down

STOMACH p.H 1-3 Contains hydrochloric acid and is highly acidic and enzymes eg. pepsin (protein). At either end of the

stomach: sphincter muscles keep acid inside the stomach.PANCREAS

Contains pancreatic juices which are released into the small intestineLARGE INTESTINE

Absorption of water and some vitamins.RECTUM

Final collection of fecesLIVER

Makes the bile, changes glucose into glycogen, i.e. controls sugar level in the bloodGALL BLADDER

Stored bile (breaks down fats/emulsifies). Contains lipases.SMALL INTESTINE pH 7-9

Where most of the digestion takes place. Pancreatic juices, Bile and Intestinal juices are added to food. The simple molecules are absorbed through the thin walls.

ANUS Opening where feces leave the body. Sphincter muscles.

CAECUM

The stomach has the role of beginning the breakdown of protein into amino acids. It does this by churning the food with gastric juice. The gastric juice, which is excreted from the walls of the stomach, contains enzymes, to break down the proteins, and acid, to kill harmful bacteria.

The small intestine produces enzymes that complete the digestion process. It is also the organ from which digested foods are absorbed into the bloodstream. In the first section of the small intestine, called the duodenum, the partly digested food is mixed with bile and pancreatic juice. The bile helps to break down fat and oil drops into smaller droplets. The pancreatic juice helps to break down carbohydrates to simple sugars, helps to complete the digestion of proteins and to break down fats into fatty acids. The pancreatic juice also helps neutralize the acid from the stomach.

The stomach has a pH of around 3, owing to the presence of hydrochloric acid. The small intestine has a pH of around 8.

The low pH of the stomach allows it to kill harmful bacteria. Also, this pH provides the conditions necessary for the enzyme pepsin to begin the breakdown of the proteins present in the food that has been ingested.

In the small intestine, on the other hand, bile from the gall bladder emulsifies the fat present in the food. This bile is alkaline and helps to neutralize the stomach acid in the food.

When drugs are being designed, scientists consider carefully where in the digestive tract the drugs should be dissolved, ready to be absorbed into the bloodstream. Scientists may need to ensure that a drug:

dissolves when it reaches a location with a specific pH

reaches its destination without being broken down. It may have been dissolved but it must still be chemically effective

is released within an appropriate timeframe.

The solubility of a drug can be affected by the nature of solvent, the amount of agitation and the temperature.

Soluble tablets will dissolve rapidly in water producing a liquid solution. Liquids entering the digestive system are absorbed more rapidly than solids. This is useful when fast-acting medication is desirable.

Some substances that are not very soluble in water can be dissolved by the addition of other substances to produce a solution without changing the therapeutic effect of the drug itself.

Drugs that dissolve in acidic solutions will be absorbed through lining of the stomach and are then taken to other parts of the body by the bloodstream. Those that dissolve in alkaline conditions will be absorbed through the walls of the small intestine and are similarly carried by the bloodstream.

Medication may be designed especially to dissolve in the intestine rather than the stomach.

It is important for scientists to test medicines thoroughly because the digestive tract can affect the drug and because the drugs may cause damaging side effects. Some drugs are broken down in the presence of acids and this may alter their effectiveness.

Some drugs may cause damage to the lining of the stomach. For example, some common drugs used in the treatment of arthritis are enteric-coated to prevent their solution in the stomach, where they may cause irritation or gastric upset.

Medication may be designed to dissolve over a period of time in order to provide access to the drug without further ingestion.

Generally, the more soluble a drug, the quicker will be its absorption and the quicker the action on the body. A drug must be stable enough to survive the body digestive system.

Drugs taken orally may be soluble in water, soluble in alcohol or not soluble in either. When an acidic drug is given in the form of a salt, it may precipitate in the stomach initially but

can be readily redissolved in the intestine and be absorbed. Some drugs are prepared as sprays to act directly on the surface of the throat or nose, or to be

absorbed through the lining. Some sprays are designed to be inhaled into the lungs. This type of administration can be very fast-acting. Nasal sprays are usually aqueous solutions. Some sprays are very fine particles of powder; others are a fine mist of dissolved particles.

Highly soluble drugs can be easily carried in the bloodstream; can act more quickly on the body. If a drug is soluble in water, it may be administered conveniently in a number of ways, including

orally (as solutions, or in capsules or tablets), by inhalation, or eye-drops, nose-drops, ear-drops.

Capsules

hard capsules contain powdered drugs in a shell of hard gelatin. soft capsules contain semiliquid and liquid in a shell of soft gelatin long acting slowly release their contents into their patient’s intestinal tract

Enteric coated are coated with a polymer substance that only breaks down in the small intestine.

Tablets most common method of administration; usually mixed with substances designed to ensure that

the drug disintegrates in the body. lubricants are used to ensure that the mixture flows through the body

coatings protect tablet, disguise taste, control rate of release; sugar coatings, enteric coatings, layered tablets.

Some drugs will dissolve better in water-alcohol or glycerol solvents and may then be administered as solutions, suspensions or emulsions.

In some circumstances, a skin application may be intended to be absorbed into the blood stream by passing through the lining of the glands. To help penetrate the lining they need to be fat-soluble. In this case, transdermal patches are used which have been impregnated with drugs such as oestrogen or nicotine.

Subdermal implants, on the other hand, are implanted into the body and the drugs are released into the lymphatic system, not the bloodstream. They may be placed inside the thigh or arm or in the stomach. This system ensures a continuous slow release of the drug required.

Some vitamins are water-soluble (including the eight B-group vitamins and Vitamin C) and some are fat-soluble (including Vitamins A, D, E and K).

Water Solublepolar water soluble excreted in urine constant supply

Fat SolubleNon-polar fat soluble stored in fat cells can reach toxic levels

MEDICAL BIONICSBiomedical

device/implantWhat its used for Biomaterials used Example

Pins, screws and plates Replace bones and repair damaged joints.

Titanium, titanium-coated stainless steel.

Titanium plate inserted into damaged skull to protect brain.

Artificial joints Replace damaged joints to allow movement.

Metals, polyethylene. Knee, wrist, shoulder, hip and elbow joints.

Pacemaker Send electrical signals to the heart to maintain a regular beat.

Titanium, polyurethane, silicon semiconductors.

Pacemaker.

Artificial valves Replace damaged or faulty valves.

May be from a human donor or pig’s valves. Mechanical valves use stainless steel and strong polyester.

Artificial valve.

Crowns and dentures Used to replace damaged or lost teeth.

Metal, porcelain, plastic and ceramics.

Artificial teeth.

Lenses Repair and aid eyesight. Silicone, Glass. Contact lenses.

Prosthetic limbs Replace damaged or unusable limbs.

Metals (titanium, alloy), polymer.

Arms, legs.

Cochlea implants Artificial hearing device that helps with hearing problems.

Bionic ear.

Biomaterials often used include:Material Example of how the material is

usedProperties that make material

biocompatibleMetals Aiding bone healing, replacement

joints.Titanium is biocompatible and doesn’t react with the body, stainless steel is strong and cheap but can rust, and cobalt alloys are expensive but last longer.

Ceramics Dentistry, joint and bone segment replacement, temporary bone repair.

Strong, non-flexible, resist corrosion, low density, and biocompatible

Plastics Repair and enhance the human body.

Can be created to suit almost any application, needs to be strong, and suited to body temp.

Polyethylene Replacement parts e.g. hips and knees

Dense. Resistant to abrasion and cutting, self-lubricating.

Silicone Breast implant, replace cartilage in small joints.

Stable, heat resistant, not damaged by light, long life span.

Historical development of artificial valves – the first implantable artificial valve was invented in 1952 but it was not until the invention of the heart-lung machine that surgeons could safely enter the heart and repair or replace hearts. In 1961, the first successful replacement of a human valve was implanted. It was made from a steel cage surrounding a silicon rubber ball.

Function of the heart:

o Valves – ensure a one way flow of blood. Prevent backflow of blood into the ventricles and aria.o Atria- the in-flow chambers, collect incoming blood and contract to transfer the blood to the ventricles.o Ventricles- the out-flow chambers. They contract and force blood away from the heart.o Major arteries – aorta and pulmonary artery. Arteries carry blood away from the heart. It is pumped

with strong pressure therefore arteries have thick muscular walls.

o Major veins – caval veins and pulmonary vein. Veins carry blood to the heart. Veins have thin walls because of low pressure. Valves are in the veins to prevent the back-flow of blood (no valves in arteries).

Heartbeat: cardiac muscle contracts and relaxes involuntarily (we don’t think about it). The average heart beat is approx. 70 beats/min. Electrical signals start in the sinoatrial node (heart’s natural pacemaker) and travel quickly from cell to cell in the muscles of the atrium causing it to contract before the ventricle does.

Interruptions to the normal rhythm of the heart:o Heart murmur – if the flow of blood is disturbed by obstructions or vibrations of the muscle walls the

flow can become turbulent and may be heard with a stethoscope. Murmurs can be an indication of leaky valves.

o Ischemia and fibrillation – the blood supply to the heart muscle is inadequate or interrupted (Ischemia). Lack of sufficient oxygen then cause the heart to cramp and shudder in an uncontrolled manner called fibrillation. May result in heart attack or death.

o Tachycardia and bradycardia – heart is either beating too fast (tachycardia) or too slow (bradycardia).o Damage to pacemaker region of heart – if the sinoatrial node is damaged or malfunctioning, or if the

electrical signals are blocked, the pattern of the heart muscle contractions becomes interrupted. Pacemakers: o Helps produce regular electrical signals and a regular heartbeat.o Battery powered generator (pulse generator) held in small titanium case.o Is powered by a special long lasting lithium battery.o Leads connect the pacemaker to the heart. Leads are made of metal coil conductor covered in a soft

plastic coating.o Where the leads attach to the heart small metal electrodes are present. Early pacemakers were unsuccessful and dangerous as they delivered electric shocks to the heart

during emergency such as a heart attack. Developments that helped the advances in the modern day pacemaker included:

o Reduced amount of voltage in devices.o Pacemakers with leads directly attached to walls of heart.o Battery power source.o Surgically implanted rather than being worn externally.o The first artificial pacemaker was implanted in 1958.o Smaller pacemaker unit.o Improvements in design, electrical circuitry, longer lasting batteries and computer technology. Faulty valves in the heart mean that the heart must work harder which can cause a heart attack or

death. If the Valves are leaky a heart murmur is heard. Symptoms include shortness of breath, tiredness, continual cough and chest pain. When heart valves become inflamed it can result in adhesions, rheumatic fever is a common cause of this type of damage.

Stenosis: The valve opening becomes narrow. Insufficiency or regurgitation: the valve does not close completely, which allows backflow of blood

and extra pressure on vital organs. Teflon/pyrolytic carbon must be biocompatible (not rejected by the body). Teflon is used for artificial

blood vessels because it is elastic, absorbent and strong. It is able to function like real blood vessels, dilating and contracting with changing blood flow.

Effects of build-up of plaque. Plaque is composed of fat and cholesterol. A build-up of plaque in the arteries can be caused by smoking, high-fat diet, being overweight and having high blood cholesterol. If a build-up of plaque occurs the following problems may become present:

o Narrowing and blockages of major vessels such as coronary arteries.o Erosion of artery walls, make them less elastic, as well as effecting blood flow.o Blood clots.o Cardiovascular disease e.g. stroke, heart attack.o Atherosclerosis- building up of the artery wall of fatty deposits which harden to form plaque. Reducing the risk- your blood carries two forms of lipoproteins, (Low density lipoproteins) LDL

transports cholesterol around the body in the blood stream. High density lipoproteins (HDL) are good cholesterol; HDL assists in removing LDL from artery walls. Removing plaque can be done in several ways:o Bypass Surgery involves taking a vein for the leg and using it to construct a new pathway for blood

around the blocked vessel.o Angioplasty: refers to repair of a blood vessel. o Ectomy; refers to the removal of the part at the start of the word.o Artificial vessel o Laser angioplasty uses a laser beam to remove plaque.o Balloon angioplasty widens the artery. The role of the skeletal system is to :

o Provide a framework to support the body.o Maintain posture.o Protect internal organs.o Provide bone for muscle attachment.o Provides movement.o Maintains calcium for bones growth and repair.o Produce blood cells in bone marrow.

The spongy bone at the end of bones is surrounded by cartilage. Bones are made of collagen (very strong, flexible protein) and calcium phosphate salt which hardens

the bone.

SYNOVIAL JOINT FUNCTION

Ball and Socket Allows movement in many directions. For example the hip joints and shoulder joints.

Hinge Movement is restricted to one plane only. For example the elbow, knee and finger joints.

Double Hinge Allows movement backwards and forwards and side to side. For example the base of a thumb.

Sliding Allow sliding movements in all directions. For example some joints in the spine and tarsal bones in the feet.

Pivot Provides rotation. For example the base of the skull and between the forearm and wrist.

Cartilage lines the end of bone and reduces friction. This allows smoother movement but if the cartilage is damaged or worn, movement becomes less smooth and may result in pain.

Synovial Fluid helps lubricate the joints. Damage to the synovial membrane can cause excessive amounts of synovial fluid to be excreted and will cause swelling of the joint.

Silicone is suitable for the use in bionics because it is biostable, has low flammability and is acid resistant and flexible over most temperature range. Some are completely insoluble in water and because they contain no carbon, they are less likely to be rejected by body tissue.

Silicone joints are more suited to small joints the fingers and toes that carry little weight because silicone can be bent and stretched many times without breaking. It is not suitable for use in heavy weight bearing joints of the body.

Ultra High Molecule Weight Polyethylene (UHMWPE) is a suitable alternative to cartilage surrounding ball and socket joints as it is biocompatible with surrounding tissue, durable (can be bent many times without wearing) and has low friction which allows ease of movement.

Artificial joints use polyethylene to reduce friction, absorb shock and lubricate the joint. Super alloys made from metals such as iron, cobalt, titanium. They are high in strength, low weight,

compatible with body tissue and corrosion and wear resistant, extremely high-impact resistance. Artificial implants can either be cemented in or not un-cemented into place. Millions of people have

been relieved of pain and disability. The glue used in cemented joints is acrylic cement, the glue eventually dried and cracked and the shaft

became loose. Un-cemented joints are hammered into place and cause trauma to the bone. As a result of this trauma the bone responds by growing into the porous surface of the implant which forms a bond between the bone and implant.

In artificial joints; ‘polyethylene’ is used to withstand wear and tear. A person cannot live if blood does not continuously flow through the body, supplying oxygen to the

cells and removing wastes; therefore life support systems are needed to sustain life during operations or while the body repairs itself.

Respiratory system involves the intake of oxygen and removal of carbon dioxide and water vapor. The exchange of oxygen and carbon dioxide gases takes place in the lungs. Air is forced into the lungs

through a process called inhalation. Air is forced out of the lungs through exhalation. Trachea – the breathing tube that brings air from the nostrils to the bronchi. Bronchi – the trachea divides into two bronchi; each bronchus leads to a lung. The bronchi divide into

smaller tubes called bronchioles. They end in tiny sacs called alveoli. Alveoli – highly folded micro-structures, the actual exchange of oxygen and carbon dioxide takes place

in the alveoli. Provides a large surface area for efficient gas exchange. Around each alveolus is a capillary network which provides an extensive supply of blood.

Air we breathe in contains 21% oxygen and 0.03% carbon dioxide. Immediately exhaled air contains about 16% oxygen and 4% carbon dioxide.

All living cells require oxygen. When the heart stops, circulation stops and cells do not receive oxygen. Cardiopulmonary resuscitation techniques (CPR) can maintain life when the heart has ceased beating.

CPR is a combination of Expired Air Resuscitation (EAR) and External Cardiac Compression (ECC). EAR, mouth to mouth or mouth to nose resuscitation aims to re-establish or maintain breathing by

artificially inflating the lungs. ECC provides artificial blood circulation by putting a rhythmic pressure on the chest at regular

intervals. This compresses the heart between the breastbone and the spinal column. ECC along with EAR may be enough to keep the heart and brain alive by providing oxygenated blood

even when the heart has stopped. Artificial lungs remove carbon dioxide from the blood and replace it with oxygen. Oxygenated blood is

pumped back into the aorta through another tube. The heart and lungs must be temporarily stopped during surgery for heart transplants and heart

implants. A heart-lung machine is used during these operations to perform the functions of the heart and lungs.

Life support systems include; Heart-lung machines, respirators, renal dialysis machines and ventilators. Monitoring devices such as ECGs and echo-cardiographs which allow heartbeat to be recorded and

problems anticipated. Ventilators – when a person can no longer breathe naturally, an artificial ventilator is used. Respirators – machines which induce artificial breathing. Air is transmitted to the lungs via a tube

inserted in the trachea.

Non-invasive or Minimally-invasive medical techniques

Non-invasive

Non-invasive diagnostic techniques include X-rays, ultrasound, thermography and MRI. X-rays – x-rays travel through some but not all materials. For example, they pass through skin tissue

but not bone. It is used to get a clear picture of internal structures, such as the skeletal system and organ placement, without invasive, exploratory surgery. This is used to diagnose limb or joint injury, fractures of the bone, large tumors and enlarged organs.

Disadvantages of X-rays – they only provide a two-dimensional view; bones often hide other tissues that cannot be seen with X-rays; over-exposure to radiation can damage tissue and cause cancer.

Ultrasound – uses ultrasonic (ultra-high frequency) sound waves. The sound waves, transmitted from a probe, penetrate the body and are reflected off internal structures. The echoes are received and analyzed by the probe and converted into an image on the screen. Ultrasound is used in diagnosis and to study fetuses in the uterus.

Thermography – uses infra-red waves and differences in body temperature to create images, and is useful in locating cancerous tumors as tumors are more active metabolically and therefore produce more heat. Thermography helps identify areas where there is restricted blood flow.

MRI – also called nuclear magnetic resonance. MRI uses radio waves and the body’s water molecules to create images. The MRI machine produces a powerful magnetic field which causes hydrogen atoms in water to line up parallel to the direction of the field. The machine then releases radio waves which cause a shift in the hydrogen atoms. This brief change is recorded and analyzed.

MRI can be used for diagnosis because not all body tissue contains the same amount of water. MRI is used to clearly identify soft tissue such as the brain and spinal cord which are encased in bone.

Minimally invasive surgery techniques

Endoscopy and keyhole surgery, laser and ultrasound technology and microsurgery. Advantages of non-invasive surgery; less risk to patient; fewer side-effects and less chance of

complications that can occur as a result of invasive surgery; faster recovery and less time needed in hospital; less need for medications, or after-surgery care, or nursing.

Endoscopy and Keyhole surgery – an endoscope is a thin plastic tube that contains flexible bundles of fibres, light is shone down one of the bundles and reflected back up another bundle to the surgeon’s eye. This illuminates the area, allowing the surgeon to carry out the necessary procedure. A tiny camera can also be placed in the tip of the endoscope.

Endoscopes are used in a number of ways; as a diagnostic tool to carry out observations or biopsy (taking a tissue sample for analysis). ; to treat minor problems using other special tools that are clipped to the end of the endoscope tip.

Endoscope Advantages – allow the surgeon to view inside the body without having to make large incisions and in some cases without having to make an incision at all.

Endoscope Disadvantages – endoscopes allow only a small area to be illuminated at a time. Endoscopy may not detect some conditions.

Laser technology – uses a very thin, high-intensity beam of light to cut and seal tissue. Advantages – laser surgery can be used with great precision to treat areas without damaging surrounding tissue. There is minimal bleeding and minimal pain and scarring from the incision.

INFORMATION SYSTEMS

Forms of energy; light, sound, mechanical, electrical, heat, kinetic, potential, nuclear potential and chemical potential.

Energy cannot be created or destroyed; only to be changed from one form to another. Example in a light bulb; electrical energy transforms to heat and light energy. Waves carry energy – waves transmit energy from one place to another. Waves can be measured in terms of their wavelength, frequency or amplitude. Frequency – the number of waves past a certain point in a given time. Hz Amplitude – the loudness or softness of a sound is determined by the energy carried by the wave. Sound waves are created by vibrating objects. A changing magnetic field produces an electric field, the energy produced by these changing fields

radiates out as waves, called electromagnetic waves. Waves can be refracted – bent, through glass.

Waves can be reflected – bounced off objects; mirror. The information transfer process involves; a code common to both parties; encoding – creating the

message so that it is in a form which can be easily sent (transmitted); the transmission of the coded message – the message must be sent and received; a decoder which puts the message into a form which can be understood.

The speed depends on the speed of encoding, the speed of transmission and the speed of decoding. Verbal and non-verbal information systems – spoken and written language are the most basic forms of

communication. Non-verbal includes pictures, symbols, body language and voice tone. Short distance and long distance – talking to one another and in small groups. Electronic and non-electronic – telephone, fax, email which require electricity. Non-electronic

communication includes mail and print media such as newspapers, books and magazines. Telecommunications – refers to methods used to instantaneously send messages and information over

long distances. Occurs through coaxial (shielded, single strand metal) cables, microwave circuits and telephone lines that transmit information using electrical signals and optic fibre cables that transmit information using light energy. Applications include telephones and satellite communications.

Transformation of energy in information transfer – Land connected telephones – have a mouthpiece (microphone) that converts sound to electric current

variations and an earpiece that converts electrical signals to sound. Sound = Electrical energy = Sound. Mobile phones – self-contained transmitters and receivers of radio waves. They function like a

telephone without being connected by wire. A local antennae transmitter (tower picks up the radio waves in a certain geographical area called a cell. Microwaves are also used to relay transmission of the message. Sound energy (you talk)= electrical energy = radio waves = transmitted via microwaves= electrical energy = sound energy (you hear message).

TV – a TV camera transforms light energy (visual images) into electrical signals (energy). The signals are amplified and transmitted in the broadcasting network. The TV detects the signals and produces an image on the screen. Audio information (sound) is transmitted simultaneously. Light and sound energy = electrical energy = light and sound energy.

Radio – consists of a microphone linked to a transmitter and a receiver linked to a loud speaker. CDs – store information (sounds) digitally. The digital signals are coded as binary patterns on the CD.

CD players use light from a laser instead of the tone arm or cartridge to read the coded message. Sound energy = electrical energy = sound energy.

Having a range of information systems enables us to communicate with many different ways. We can send and receive sounds, pictures, written words and data in a range of forms over different distances.

Radio/Fax, TV and CD players are all electronic (require electricity) and are capable of transmitting information over long distances.

Information transmission and waves

Electromagnetic radiation comes from the sun, stars and galaxies. It can also be made by humans, for example, use in microwave ovens, walkie-talkies, CB radios and infra-red remotes for controller doors.

EM waves can travel through empty space (a vacuum) at a uniform speed. Therefore, EM waves act as wireless conductors of energy and can be modulated to carry different types of information.

The EM spectrum shows the range of different types of electromagnetic radiation (or waves). These wave types all travel at the same speed through the same material.

They differ only in their frequency and therefore their wavelength. Our eyes can detect a range of particular frequencies of EM radiation – we call this light.

Radio waves = micro waves= infra-red = visible light = UV = X-rays = Gamma Advantages of microwaves and radio waves in communication technologies – can travel through air

without a wire; can be broadcasted to a huge audience over large distances. Disadvantages – broadcasting over a wide area means that a lot of energy is wasted.

Uses of different wave properties used in communication systems

The properties of energy from the electromagnetic spectrum that make it useful in communication technologies include; all energy from EM spectrum travel at the speed of light (3*10^8m/s). ability to travel in a straight line.

Visible light (we see). The wavelength is 7*10^-7 m to 3*10^-7. But to see someone we need light-of-sight transmission.

Radio waves (TV, FM and AM) have the longest wavelength = lowest frequency of the EM waves. 300kHz to 3 000 000 000 kHz. Radio waves do not penetrate all objects. They can easily be reflected and bend around large obstacles such as buildings and hills. Radio waves do not need line-of-sight transmission.

Micro waves also have a long wavelength = 10^-2 meters to 10^-4 meters. Microwaves have limited penetration.

A radio’s receiver is the antenna. The antenna picks up many different signals but its length will be more suited to particular frequencies.

An AM radio wave can carry a coded message by changing its amplitude. An FM radio wave can carry a coded audio signal by changing its frequency. The quality of reception of

FM radio is better than AM. A pure radio wave has a constant frequency and amplitude. If modulation involves changing the

amplitude, AM radio wave are produced. TV uses both AM for picture and FM for sound.

Geostationary satellite

Geostationary satellite revolves at a height of 36 000 kms above the Earth’s surface, staying above the same place on the equator. The satellites orbit takes 24 hours and therefore it is stationary relative to the movement of the rotation of the Earth.

The speed of the radio signal is given by the equation SPEED = distance/time The speed of travel is 3x10^8 m/s. The satellite must be at a height where its revolution period is the same as that of the Earth’s period

of rotation. This is because satellite must always face geostationary satellite communicating with it. Each geostationary satellite can see a third of the globe, but they have a poor view of polar-regions. An Earth-based satellite dish must face a fixed direction if it remains in the same location with respect

to the geostationary satellite. The parabolic shape of the dish focuses signals into the central point. The largest provider of international satellite services is Intelsat.

Information transmission and electrical impulses

Computer-based communication systems used in faxes, barcodes, digital recording and so on, are examples of communication technologies that transform one type of energy (sound or light) into electrical energy.

To transmit images using digital technologies, the images are scanned along very thin lines and the information is converted to digital signals.

The signals travel by a telephone line and is received by a fax at the other end, which decodes the signal and makes a replica, then prints the message.

Faxes – light energy is transformed into electrical signals (digitalized) and transmitted through the telephone line where it is converted back to light. Light energy = electrical energy = light energy.

The numbers used are binary; 1s or 0s. each binary digit is called a bit. Digitalization involves converting sound or light into computer language (a code), transmitting it and

converting it back to its original form at the receiving end. Digital circuits such as those in computers, cannot process information in the form of waves.

Computers can process numbers. In an analogue system, information is transmitted in the form of a wave. Analogue circuitry is able to process the information into a wave, its amplitude must be measured and

converted into a number – but the amplitude is continually changing. A digital circuit cannot process a number that keeps changing.

Optical fibre communication systems

In optical fibre communication systems, electrical energy is converted to light energy. An optical fibre is a single hair-like fine filament made from molten silica glass. The fibres are

constructed in such a way that light can be transmitted through them with minimal loss of light energy by total internal reflection.

A fibre optic cable is made up of a large number of individual optic fibres, bound together around a central core.

Light cannot travel around corners unless it is reflected. The principle of total internal reflection occurs when the rod (fibre) is made up of different substances

with different densities, such as glass and air. In an optical fibre, a transparent glass rod forms the inner core and there is an outer coating of

different density. The properties mean that optical fibres allow images to be transmitted around corners and increase

the quantity and accuracy of the transmission of information. Optical fibres are replacing metal wire as the transmission medium for high-speed, high-capacity

communication. Fibre optic cables – carry information as light energy. They can therefore transmit enormous amounts

of information per second. Are able to send more than one call on the same link with the same quality of signal at both ends. The transmission is very fast and it is not subject to electrical interferences from external sources. However they do require boosters at intervals along their length in order to maintain signal strength.

Metal cables – carry information as electrical energy. The transmission can therefore be subject to electrical interference from external sources, making it a less reliable means of transmission.

Greater carrying capacity through fibre optic cables than through copper cables. Much faster rate of information transfer through fibre optic cables than through copper cables. Better security in optic fibre (no interference). Cost – more for fibre optic cables than copper cables.

DISASTERS

Disasters are catastrophic events associated with large-scale environmental or structural damage and loss of life, often occurring without warning.

Natural disasters include drought, earthquake, storms and floods. In December 2004; the entire earth experienced an undersea megathrust earthquake in the Indian

Ocean, magnitude was 9.1 and 9.3; killed around 250 000 people in fourteen countries. Cyclone Tracy – Darwin December 1974 – 49 people died, 16 missing at sea. Hundreds of millions of

dollars’ worth of damage. Floods – Queensland in late 2010/2011, causing mass evacuations and killing 35 people. Cost billions

of dollars from damage. Disasters associated with human activity include fires, maritime disasters, nuclear and industrial

accidents, air crashes and rail accidents. Major terrorist attack by Al-Qaeda on the US 11 September 2001 killed nearly 3000 people.

Granville train disaster – January 1977; 80 people dead. Some disasters are a combination of nature and human activity – dust storms, shipwrecks, landslides,

bushfires. Black Saturday bushfires – February 2009 in Victoria – extreme weather conditions, 46.7 C. fire travelled up to 100km/h left 173 dead, 414 injured and thousands homeless. They were a result of human activity and a combination of high temps, low humidity, high wind speeds, years of drought.

Technologies used to reduce damage and future monitoring: Research in the study of earthquakes and their effects, where they occur, how big and how often and

the study of the nature of bushfires. Development of building designs aimed to prevent collapse and able to withstand large force. Better warning and alerting of people in anticipation of disasters. Warnings to give estimate of impact and intensity of the effects and the time they will occur. A natural disaster refers to an event or occurrence resulting from natural causes, independently of

human intervention and either could not be foreseen and could not be guarded against.

Monitoring and predicting weather patterns

Atmospheric pressure is the force per unit area exerted on a surface by a liquid or a gas. Air exerts pressure, air pressure decreases rapidly with height. Hectopascals is the unit of air pressure. An aneroid barometer is used to measure air pressure. When a wind storm or rain storm is about to occur or when a cold front or warm front moves through.

Weather stations and observers around Australia make their observations and measurements at the same time each day. Weather maps show how air pressure changes. Isobars on weather maps join places having the same atmospheric pressure.

In the southern hemisphere, air currents move anti-clockwise around centers of high pressure and clockwise around centers of low pressure.

Winds are strong when isobars are close together. Pressure in the center of a tropical cyclone or tornado is much lower than normal air pressure, the air

bursts out toward the area of low pressure. At the surface of a tropical cyclone, winds spiral inwards towards the eye of the cyclone in a clockwise

direction and form an intense vortex around the eye. Wind speed increases dramatically, as the cyclone moves away or decays, the air pressure rises again.

Technological advances include satellites, radar and laser technology and computer technology. First weather satellite was launched by the USA in 1960. There are now a number of weather satellites in orbit which together, provide cloud pictures for the

entire globe twice a day. Satellite photographs of cloud patterns and cloud formations enable weather forecasters to detect

fronts such as major cold fronts and cyclone systems. Radar waves are used to observe cloud formation, predict storm movements and measure variation of

wind velocity.

Some Disasters are still not easy to predict

Earthquakes happen as a result of the shock of (seismic) waves of energy which are released by the movement or fracturing of rock in the Earth’s crust and volcanic eruptions.

Earthquakes, produce different types of seismic waves; P, S and L waves. P waves or primary waves are the first seismic waves to arrive, they travel the fastest about 8km/second. P waves can travel through any kind of material whether solid, liquid or gas. S waves follow P waves, travel at 3.2-4.5km/s. can only travel through solids. L waves are surface waves which travel at 2 km/second. Most destruction comes from the slow moving L waves.

L waves are longitudinal type waves which cause the material through which they travel to vibrate in the direction of the wave. The energy carried by L waves is transferred to the Earth’s surface and to buildings, roads, bridges and other structures; the energy is transformed into sound energy.

The epicenter of an earthquake is point on the Earth’s surface that lies directly above the focus or of an earthquake. Towns; cities in the area of the epicenter will feel the most impact of an earthquake. The difference in time of arrival of P and S waves can be used to locate an earthquake’s epicenter.

Seismic waves travel out from the focus in all directions. The further a seismometer is from the earthquake, the greater the time lapse between each type of wave.

A seismometer receives seismic waves. A seismograph records seismic waves, they measure the shocks and vibrations caused by the movement of rocks.

The Richter scale provides the most common description of an earthquake’s intensity. The scale is a world-wide standard which ranges from 0-9.

The Mercalli scale ranges from level 1 to level 12. Even though the nature of earthquakes and major earthquake regions of the world are well

understood, scientists cannot predict with certainty the movements of the Earth’s crust. Seismic waves travel quite fast, and therefore earthquake warnings are usually too slow to alert people to them. Many earthquakes give no warning sign.

Bushfires

Uncontrollable wildfire which can destroy life and property occurs in very specific conditions on certain days. The conditions that can combine to trigger a bushfire include dry weather, high temperatures, strong winds, low humidity, and dry vegetation.

Speed of a bushfire is determined by factors such as slope of the land and the intensity of the wind. Fire travels twice as quickly up a 10 C slope as it does on level ground. Chemical potential energy is the energy stored in fuel (vegetation). The ignition point is triggered by

something (match) the heat energy is transformed to light and sound energy.

Controlled burns are also known as prescribed burns, fuel management or hazard-reduction burning. Controlled burns are usually done at times of the year when fires can be controlled. They are cooler burns which aim to; minimize risk of bushfires; make wildfire easier to control by thinning or removing some of the vegetation; reduce the chances of fire starting.

Backburns refer to burning that is done to manage a fire that has already started. Some native plants require hot fires for seed germination. These natural fires vary in frequency, severity, season and patterns of burning.

Eucalyptus promotes the spread of fire as they contain oil. Leaf litter that tends to accumulate on the ground and may assist in the spread of fire. The tough leaves and branches are both flammable and slow to decompose. Eucalypts with rough bark provide a ready-made fuel ladder to the leaves in the crowns of trees. Resources which are used to retard the progress of fire; Water – is pumped from tankers and

backpacks or dropped from the air by helicopters, fixed-wing aircraft and water-scooping air tankers. ; natural plants – most eucalypts forests and rainforests can retard the progress of fire, examples – swamp oak, river oak, brush box, cedar wattle.

Precautions to minimize damage by bushfires; clearing litter and wood piles, clean gutters, removing household rubbish and garden clippings, store flammable liquids in metal containers.

Fire regulations and precautions for urban planning which aim to avoid inappropriate development in areas of high fire risk.

Radiated heat and smoke are the main dangers in a bushfire. If caught in a bushfire in the open – assess the distance, direction and velocity of fire,, avoid dense

scrub, stay in a cleared area, cover the body and exposed skin, cover nose and mouth with wet cloth to lessen the effect of smoke.

If caught in bushfire in the house – fill the bath and buckets with water, close windows, draw blinds, stay in the house, turn off electricity, put out small embers.

Warning devices can be used to detect disasters – a trigger turns a switch on and electrical energy is converted to sound and or light

Smoke detectors – sense presence of smoke in a building and warn occupants with an alarm. Light energy – electrical energy – sound energy.

Fire alarms sense the presence of flaming fires (with little smoke) Sprinkler systems detect heat. Fire extinguishers should be based on the most like source of fire in the area – A type – for rubbish,

wood, and paper. B type – for liquids such as oil and grease. E type – for electrical fires. A fire alarm is made up of a small electronic alarm that usually operates on a 9 volt battery, a printed

circuit board, a sensing chamber and a small alarm such as a bell or horn. Smoke alarms and fire detectors should not be installed near appliances such as air vents and air

conditioners where the air flow could prevent the smoke alarm from sensing smoke particles. They should be installed in stairwells and in bedroom and in areas that are most accessible.

Emergency services assist in the prevention and/or minimization of disasters. Help services include the police, fire brigade, ambulance, State Emergency Service, Rural Fire Service

and community organizations. Technological developments have improved our ability to prepare for disasters. Bushfires – speed of data collection and analysis of weather patterns. This enables prediction of bad

fire seasons. Earthquakes – a global network of more than 3000 seismographs helps scientists to locate the

epicenter of an earthquake quickly. Meteorology – the precision and detail of observation from weather satellites has improved

enormously. Individual thunderstorms can now be identified, and disasters associated with weather systems more close monitored. Satellite also observe complete cloud formations associated with cyclones, cold fronts and other weather systems.