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Senior science - All core topics covered
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Chapter 1 Lifestyle Chemistry
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1. The use of a substance depends on its physical and chemical properties
1.1. Identify that a wide range of substances are used daily as part of our: -‐ Food -‐ Hygiene -‐ Maintenance of our health Food
• Consists of substances such as simple and complex carbohydrates, protein, fats and oils, vitamins, minerals, water, acids, bases, alcohols, esters and many others.
Hygiene
• Soap, shampoo, deodorant, toothpaste, cleansing creams and lotions, are mixtures of chemicals like glycerol, fats and oils, salts and water.
Maintenance of our Health
• Household cleaners and pesticides may be mixtures or compounds and often contain methylated spirits, sodium hydroxide and salts
1.2.Process and analyze information to identify the range of chemicals used in every day living including: Detergent, Lubricant, Pesticide, Solvent, Metal cleaner, Body hygiene chemicals, Cosmetic And outline any precautions when using them
Chemical Use Precautions Detergents • Cleans dishes and
clothes • Corrosive = keep away
from eyes • Toxic = do not ingest
Lubricants • Reduces friction e.g. in bikes, cars and machinery
• Flammable = keep away from flames
Pesticides • Kill insects Toxic = do not swallow, inhale, spill on skin
Solvents • To dissolve other stuff e.g. turps, water
• Some are flammable, toxic, corrosive
Metal cleaners
• Removes tarnish from metals
• May be toxic or corrosive
Body hygiene chemicals
• Soap, deodorant = reduce body odour. Antiseptics = kill bacteria
• Many are toxic and will cause allergic reactions if swallowed
Cosmetics • Perfume = change smell. Make up =
• Sprays may be dangerous to inhale
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1.3.Explain that mixtures can be: -‐ Solutions that contain dissolved substances and are uniform throughout -‐ Suspensions containing particles that settle out, or form layers quickly -‐ Colloids with particles that remain suspended for long periods of time and include: Liquid-‐in-‐liquid (emulsion): oil-‐in-‐water + water-‐in-‐oil Gas-‐in-‐liquid (foams) Solution
• Is when a solvent and a solute completely mix and form a uniform or homogenous mixture.
• They allow light to pass through them without scattering Types
• Solid dissolved in a liquid = saltwater • Gas dissolved in a liquid = oxygen in water • Liquid in liquid = soft drink
Suspension
• A mixture of fine particles suspended into a liquid, which can be called a heterogeneous mixture.
• The particles will settle on standing and can be filtered with filter paper. • Light doesn’t pass through
Types -‐ Solid particles suspended in a liquid = soluble aspirin -‐ Liquid particles suspended in a liquid = fresh milk
Colloid
• A homogenous uniform suspension Emulsified suspension • Light scatters
Types -‐ Emulsions:
-‐ Oil in water = homogenized milk -‐ Water in oil = mayonnaise
-‐ Gas particles suspended in a liquid (foam) = shaving cream -‐ Solid particles suspended in a liquid = paint
change appearance Preservatives • Prevent bacteria
growing in food • Eat minimal amounts
because they can have negative effects
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1.5. Plan, select appropriate equipment or resources for and perform a first-‐hand investigation to produce a range of suspensions and colloids that are used by consumers including -‐ Beaten or whisked eggs -‐ Salad dressing (oil/vinegar) -‐ Mayonnaise Beaten or whisked eggs
• When an egg is cracked and whisked it forms a homogenous mixture even though before being cracked it a suspension (the egg yolk is suspended in the egg white
• Therefore beaten or whisked eggs is a colloid Salad dressing
• The vinegar was poured into the oil and it was shaken until the mixture looked uniform
• After 1 minute of rest the mixture became suspended, with the olive oil hovering over the vinegar
• Therefore salad dressing is a suspension. Mayonnaise
• Therefore mayonnaise is an emulsified colloid with the egg yolks acting as
the emulsifier for the vinegar and the oil.
1.6. Use first-‐hand or secondary sources to gather, process , analyze and present information to identify examples of suspensions and colloids and outline one advantage of a mixture being in each form
Ingredients Method -‐ ¼ teaspoon of sugar -‐ ½ cup of vegetable oil -‐ ¼ teaspoon of salt -‐ ½ teaspoon of mustard -‐ 2 egg yolks -‐ ½ cup of vinegar
1. Mix dry ingredients and mustard
2. Beat egg yolks 3. Add step 1 and 2 together and
mix well 4. Add half the vinegar slowly and
mix well 5. Add 3 tablespoons of oil one
drop at a time, beating vigorously each time
6. Beat in the remaining vinegar 7. Add the remaining oil a
tablespoon at a time -‐ beating at the same time
8. Cover the beaker with glad wrap and leave to rest
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Suspension • Pot of tea with tealeaves. • Advantage because parts can be separated easily, after a while the
leaves will fall to the bottom making it easy to pour the liquid into another mug
Colloid • Margarine • Advantage because of the smooth texture, allows the margarine to be
spread easily 1.7. Perform first-‐hand investigations to demonstrate the effect of surface tension on: -‐ The shape of liquid drops -‐ The formation of menisci -‐ The ability of some insects to walk on water
• Surface tension is the result of strong forces between molecules in a liquid, pulling them inward.
Shape shape of liquid drops
• Unbalanced forces on particles at the surface pull the liquid into around spherical shape
The formation of the menisci • Meniscus is the curve in the upper surface of a liquid I a container. • Concave menisci is when molecules have a stronger attraction to each
other (cohesion) • Convex menisci is when molecules have a stronger attraction to the
container (adhesion) The ability of some insects to walk on water
• Pour some water onto a watch glass until it is full. • Carefully place a needle, horizontally, on the surface of the water. • The needle floats because of the surface tension, a combination of the
water pushing up and the strength of the surface film that holds up the needle.
1.8. Explain surface tension in terms of the forces experienced by particles at the surface of a liquid
• Forces of attraction between the particles in a liquid hold it together • At the surface of the liquid, particles in contract with the air are attracted
downwards to other liquid particles but there is no balancing attraction upwards
• Thus the result is for particles to pull together as if there is a skin on the surface
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1.9. Describe surfactants as substances that affect the surface tension of a liquid
• Surfactants = surface acting agent, one that lowers the surface tension of a liquid
• E.g. Soap or detergent • Surfactants are useful as they break the surface tension of the water
which allows the them to clean surfaces
1.10. Process and present diagrammatic information to describe the effects of soaps, skin cleansers and shampoos on the solubility of oil
• The process of removing dirt from surfaces using a surfactant is shown:
Step 1
• The surfactant is added to the water containing the dirty substance • The soapy water wets the surface and the grease covering it
Step 2 • The hydrophobic end of the molecule attaches its self to the grease, whilst
the hydrophilic end pulls against it Step 3
• The grease then becomes detached from the surface and remains suspended in the soapy water until it is washed away
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2. A wide range of cleaning products are made from colloids and
surfactants 2.1. Perform a first-‐hand investigation to prepare an emulsion and compare its properties to those of a solution and suspension
• Emulsions are mixtures of two immiscible liquids such as oil and water that are suspended in one another indefinitely.
• They contain emulsifying agents that stabilize them.
2.2. State the relationship between the properties of an emulsion and the types of molecules present Water based (oil in water)
• Such as hand lotions, face cleansing lotions and conditioners, contain some oil or fat.
• They are used to moisturize or protect the skin and hair by placing oil onto the surface.
• These are miscible with water this means that if a small amount is placed into water and shaken or stirred it will remain suspended.
• The types of surfactant molecules present are large molecules with very polar chemical groups at one end.
• This end becomes attracted to the polar
Homogenous
Homogenous
Homogenous
Heterogeneous
No
Yes No
Yes
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water molecules. • The other non-‐polar end of the surfactant is attracted to the non-‐polar oil
molecules. • Many of the surfactant molecules become positioned around the very
small droplets of oil, preventing them from merging together Oil based (water in oil)
• Such as cold creams, night creams and hair creams, contain some water.
• These are immiscible with water and so if a small amount is placed into water, the emulsion will not be maintained.
• They are useful to cleanse the skin, moisturize very dry skin and hold hair in place.
• The types of surfactant molecules present in water-‐in-‐oil based emulsions are long starch molecules or protein chains.
• The chains wind among minute water droplets and prevent them from merging together
2.4. Outline the purpose of the emulsifying agent in a range of consumer cleaning products Anionic
• The molecules in emulsifying agents that are used in dishwashing and laundry detergents have a negative end when they dissolve.
• This allows them to keep oily substances away from any article that has negatively charged surfaces, such as glass and crockery.
Cationic • The molecules in emulsifying agents that are used in fabric softeners and
hair conditioners have a positive end when they dissolve. • This allows them to keep oily substances away from any article that has
positively charged surfaces, as is often the case with plastic. Non – ionic
• They do not ionize in solution meaning the molecules are polar but do not contain electrically charged ions.
• Suitable for detergents in front loading machines that depend largely on friction for cleansing and not so much on the detergents cleaning ability
Amphoteric • These are molecules in emulsifying agents that are used in personal
cleaning products. • They can have positive ends in alkaline solutions and negative ends in
acidic solutions. • This allows them to keep oily substances away from some objects that
have positively charged surfaces or negatively charged surfaces they are not strong cleaners.
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2.5. Identify that soaps and detergents are emulsifying agents and surfactants
• Soaps and detergents are surfactants because = they lower the surface tension allowing water to come into closer contact with grease/oil/dirt
• 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
2.6. Explain why cleaning agents must be surfactants and emulsifiers • A surfactant is needed to reduce the surface tension and allow the water
to wet the surface thoroughly • An emulsifier is needed to remove the grease/oil/dirt from the surface
and keep it suspended in the water so it can be washed away
2.7. Define the term biodegradable • The ability of Substance to be broken down under the action of bacteria
and the other decomposers in the environment.
2.8. Discuss the biodegradability of soaps and soapless detergents
• Microorganisms break down soap to smaller naturally occurring molecules.
• Soapless or synthetic detergents were not broken down by microorganisms and remained in water systems creating foam.
• Modern detergents, although still produced synthetically, can be broken down by micro-‐organisms and so are considered to be biodegradable
• They have an added advantage over soap in that they are effective as cleaning agents in hard water and in cold water
Not in the syllabus: Long (more than 18 atoms) hydrocarbon chain = hard soap doesn’t mix well with water: sodium Short hydrocarbon chain (less than 18) = soft soap irritable to the skin: Potassium
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3. Cleaning products used on the human body must be compatible with the physical and chemical properties
of the skin 3.1. Perform a first-‐hand investigation to examine prepared slides of human skin
Part of skin Function
Sweat glands • Excretion of water, minerals and urea
• Control body temp Nerve endings • Collect info about temp and
pressure from the environment Hair follicles • Growth of hair Oil (sebaceous) glands • Make slightly acidic oil to
protect skin Hair muscles • Contract to make hairs stand up
in the cold Blood vessels • Supply food and oxygen to all
skin cells and remove their wastes
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3.2. Identify the role of the skin as: an organ to separate the body from the external environment, an organ assisting body temperature control and an organ to protect against entry by disease-‐causing organisms 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 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, 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: -‐ The shedding of the top layer of skin helps prevent the entry of disease
causing organisms. -‐ 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.
3.3. Define the term microflora and discuss the role of the microflora on skin in different parts of the body
• 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).
• The presence of the microflora limits the resources available for pathogenic bacteria that may be able to survive the acidic, salty environment.
• The microflora also increase the acidic nature of the skin therefore making it even more inhospitable to many pathogens.
• Dry areas have a smaller population as opposed to moister areas such as the armpits
3.4. Discuss the term pH in terms of its ability to describe the acidity of a substance
• The pH scale can be used very effectively to describe the degree of acidity of a substance.
• The pH scale has the range of 0-‐14, where a pH of 7 is regarded as neutral. • Substances with a pH below 7 are regarded as acidic and substances with
a pH above 7 are regarded as alkaline.
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• Indicators include: litmus paper, universal indicator paper or universal indicator solution, methyl orange or phenolphthalein
3.5. Perform first-‐hand investigations to measure the pH values of a range of skin and hair products
• Used products such as soaps, shampoos and detergents • We dissolved a measured amount of each substance into water and added
a couple of drops of universal indicator and tested with pH paper.
3.6. Explain the relationship between the natural pH of the skin and the action of: microflora, natural oil produced by glands in the skin and perspiration
**Remembering the skins pH is 5.5, so it is slightly acidic** Microflora
• Pathogenic microorganisms do not survive in an acidic environment • The natural microflora are adapted to the acid conditions of the skin so
they are able to live there they contribute to the maintenance of the acidic environment
Natural oil produced by glands in the skin • The slightly acidic pH of the skin is largely as a result of the production of
oil by oil glands • Also the microflora feed on this oil and produce acids to also help
maintain the acidity Perspiration
• Sweat contributes to the natural pH of the skin. • Sweat from exercise is not as acidic as from heat and heat is not as acidic
then from fear
3.7. Identify data sources, plan, choose equipment or resources for, and perform a first-‐hand investigation to test manufacturers’ claim(s) on a commercial product such as soap, shampoo or shower gel and use the available evidence to analyze the results and discuss the validity of the claim(s)
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Johnston’s moisturizing body wash claimed to have pH of 5.5 • Dissolved a small amount of the product into water and tested it first with
pH paper and then used the universal indicator solution. • Then compared the colors obtained from the tests to the pH scale • Claim was valid because both tested showed pH of 5.5
3.8. Identify and explain the use of common components of body soaps, cleansers and shampoos and the reason for their use
• The common components of most skin soaps, cleansers and shampoos are: surfactants, oils, and fragrances, dyes, pH balances and ant microbe agents.
• The pH of these products should be compatible with that of the skin. Common components of soap, cleansers
and shampoos Reasons for their use
Surfactants/emulsifiers To help water attach to and remove oil particles and dirt and allow the water to carry these away
Oils To replace natural skin oils and protect the skin or hair from becoming dry
Fragrances To make the product more attractive to customers
Dyes To make the product more attractive to customers
pH balances To maintain the skins pH of 5.5 Ant microbe agents To destroy or slow the growth of
unwanted microbes
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4. The nature of a solvent plays an important role in the application of a
mixture 4.1. Perform an investigation to gather data comparing the rate at which capsules, tablets, enteric-‐coated tablets and slow release tablets dissolve Capsules
• Contain the active drug within a hard or soft gelatin covering • The gelatin capsule dissolves readily I the stomach fluids and the contents
are released Tablets
• Designed to hold together until swallowed • After entering the stomach they disintegrate quickly
Slow release tablets • Release their contents slowly into the digestive tract so that the effect of
the drug can be maintained over a much longer period of time Enteric-‐coated tablets
• Are specifically designed to stay intact when in the stomach so that the active ingredient does not irritate the stomach
• The active ingredient is released into the alkaline environment o the small intestine and then absorbed into the blood stream
Experiment
• Placed each one in both alcohol and water. • As soon as placed in the liquid the stopwatch was started recording the
times
4.2. Identify water and alcohol as commonly used solvents
• Substances that dissolve in water: sugar and salt • Substances that dissolve in alcohol: grease and oil
4.3. Identify cosmetics and external medications where water is the solvent • Water is used as a solvent for facial cleaners, hair shampoo, conditioners,
moisturizers and some creams (oil-‐in-‐water emulsions). • Antiseptic solutions (e.g. Dettol) are dissolved in water before being used
to bathe wounds.
**Remembering** -‐ Solution = solvent dissolves solute -‐ Solute = substance that gets dissolved -‐ Solvent = does the dissolving
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4.4. Identify cosmetics and external medications where alcohol is the solvent
• Alcohol is used as a solvent for astringents such as facial toner and aftershave, some antiseptics, perfumes, hair sprays and hair revitalizers and personal insect repellents.
• Iodine is dissolved in alcohol for use as a common antiseptic • Alcohol is also used in spray on painkillers.
4.5. Explain the relationship between the properties of solvents and their use in cosmetics and external medications Water
• Is a polar substance and is able to dissolve a wide range of polar and ionic substances.
• This makes water very useful for -‐ The base for emulsions in many cosmetics and medicines -‐ Dissolving many medicines before swallowing -‐ Diluting medicines so they are in the correct concentration
Alcohol • Has a non polar end and a partly charged end this makes it a useful
solvent as it can mix with water, dissolve polar substances, ionic substances and also some non polar substances
• It dissolves some medicines that are not soluble in water • Has a lower boiling point than water and thus evaporates more readily,
and better for some situations
4.6. Identify data sources, gather, process, analyze and present information from secondary sources to identify how subdermal implants release their medication
• Subdermal implant = device placed under the skin to release drugs into the body at a controlled rate
• Advantages: -‐ Receive drug regularly at a controlled rate -‐ No need to remember to take the drug -‐ The drug goes directly into the bloodstream • Examples: contraceptive purposes, insulin for diabetics • Dermal patches = do the same as a subdermal implant but on the outside
of the skin only useful for drugs with molecules small enough to pass through the skin e.g. nicotine
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5. The solubility of materials used in drugs has an effect on the way in which the body responds to them 5.1. Identify the parts of the digestive system
• the function of the digestive system is to break up food molecules until they are small enough to pass through the walls of the blood vessels and into the blood and furthermore into the cells
Part of digestive system Function Teeth Physically break up food into small pieces Salivary glands Produce an enzyme which starts the chemical
digestion/breakdown of starch into glucose Oesphagus/food pipe Carries food from the mouth to the stomach Stomach Produces hydrochloric acid and an enzyme called
pepsin which digests/breaks down proteins into amino acids
Small intestine Secretes enzymes to digest food. Completes the digestion of food. Absorbs digested food through its
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wall into blood vessels and lymph vessels Large intestine Undigested food passes out of the body as fasces.
Absorbs water and some vitamins Anus Ring of muscle at the end of the large intestine. Liver Produces bile which emulsifies fats into small droplets
so they can be digested Pancreas Produces enzymes to digest food in the small intestine Gall bladder Stores bile until it is needed
5.2. Outline the role of the stomach and the small intestine in breaking down food 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.
5.3. Discuss the difference in pH of the stomach and the small intestine Stomach
• Has a pH of around 3, owing to the presence of hydrochloric acid. • 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.
Small intestine • 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. • The alkaline environment allows other enzymes like lipase, amylase and
protease to continue the digestion of the protein, starch and fat molecules present in the food.
5.5. Account for the absorption of a drug and its action on the body in terms of its solubility
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Orally (tablet, capsule etc.) • 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's digestive system. • Absorption can also be affected by the presence of other substances and
the nature of membranes through which the drug must be absorbed. • 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.
Sprays • 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.
Creams • Skin applications are usually intended to reach the skin surface or the
lining of the sebaceous glands under the skin. • Many ingredients of skin applications are soluble in fats and oils, such as
the type found in the layers of the skin.
5.6. Identify that the manner of administration of a drug may be related to its solubility Oral application
• 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 as eye-‐drops, nose-‐drops or eardrops.
• Some drugs will dissolve better in water-‐alcohol or glycerol solvents and may then be administered as solutions, suspensions or emulsions.
Skin application • 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 estrogen 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.
5.7. Explain why the knowledge of the solubility of materials can be used to design drugs for specific purposes
• 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.
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• 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 -‐ Is released within an appropriate timeframe. • 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.
5.8. Identify vitamins that are water-‐soluble and those that are fat-‐soluble • A, D, E and K are fat soluble • B and C are water soluble
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Chapter 2 Medical Technology:
Bionics
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1. Increases in Scientific understanding and technological advances have broadened options for
maintaining humans as Functioning organism
Biomaterials • Biomaterials are substances that can be safely placed in contact with
living tissue without the tissue reacting against it. • They are synthesized from commercially available materials or purified
from naturally occurring substances like coral. • Biomedical device is an implant or device, made from biomaterials, which
can be placed in the body and will function there • The main biomaterials are:
Metals • Also known as alloys • The main alloys used in biomaterials are:
Titanium alloy: Biocompatible, unreactive, strong, easy to mold or shape, wears out easily Iron alloy (stainless steel): Strong, easy to work with, cheap to manufacture, tendency to corrode, same tensile strength as titanium but more denser Cobalt alloy: more expensive than stainless steel but more resistant to corrosion
Ceramics • Strong, non–flexible, resist corrosion, low density, easily shaped when
wet, heat = permanently rigid
Plastics • Also known as polymers • The main polymers are:
Polyethylene: linear molecule = ultra high molecule weight polyethylene (UHMWPE). Very strong, denser than normal polyethylene, resistant to abrasion and cutting, impact and corrosion resistant, self lubricating, tends to stretch under heavy loads Silicones (experiment): withstands pressure, flexible, stretchy, strong, easy to cut but not to tear, unreactive, becomes weak and falls apart when rubbed against metal
Replaceable parts
Eyes • Cataracts are when the lens of the eye becomes cloudy, so that the person
can not see clearly • Cataract surgery = a small cut is made near the front of the lens –
ultrasound dissolved the damaged lens – vacuumed away – replacement is inserted
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Teeth • Crowns are used to cover broken teeth, or teeth were the nerve has died
Ear • Cochlear implant is a bionic ear, pioneered by a group led by Aus scientist,
Graeme Clarke. It is not the same as a hearing aid because implanted are surgically implanted.
• Some people are deaf because the inner ear is damaged. • Cochlear implants replaces the damaged part by converting sound to
electrical impulses and sending them to the brain. • There are five main parts of the bionic ear: 1. Microphone: picks up sound 2. Speech processor: select and arrange sounds picked up by the
microphone 3. Transmitter: receive signals from the speech processor and pass them
through the skin to the receiver/ stimulator 4. Receiver/stimulator: transform signals to electrical impulses 5. Electrodes: collects the impulses from the stimulator and sends them to
the brain via the auditory (hearing) nerve • Historical developments od cochlear implants: 1950’s: auditory nerve stimulated 1961: William house implemented device 1978: Graeme Clark implanted first multi-‐channel cochlear implant 1980’s: many cochlear implants used, with speech processor in pocket
1990’s: miniaturization Today: external component of implant fits behind the ear
Heart • Valve is a device that controls the direction of flow of blood through the
veins of the heart. • The valve allows the blood to flow from left to right but if it try’s to go
right to left (backwards) it will not be able to get through.
• It is able to get through backwards an artificial valve is available • Historical developments of the artificial valve: 1950’s: structure of heart valves studied using cadavers 1960: ball-‐in-‐cage valves implanted 1962: valves transplanted from cadavers with healthy hearts 1971: artificial tilt valves implemented 1978: valves that work like a bileaflet disc implanted
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1990’s: wide use of transplants of valves from pulmonary veins to aorta
Biomedical Devices
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2. The regular beating of the heart and continuity of the flow of blood through the heart and around the
body is needed to maintain good health
The heart
Structure of the heart • Top two chambers = atria. Bottom two chambers = ventricles. • Atria pumps blood from the cells of the body through the veins • Ventricles pumps blood into arteries which carry the blood around the
body • The ventricles have thicker walls because they have to pump blood
around the body • Diagram of the heart:
• Valves prevent blood from flowing backwards • The valves have strong flaps which are attached to cords connecting with
contracting muscles allowing them to only open one way • There are three types of blood vessels: Artery: carry blood away from the heart (thick muscular wall)
Vein: carry blood back to the heart (thinner) Capillary: substances diffuse in and out of them (tiny)
Circulation of blood • The five steps of the circulation of blood are: 1. Deoxygenated blood comes into the right atrium, then to the right
ventricle of the heart.
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2. From the right ventricle it is pumped to the lungs where it becomes oxygenated.
3. Once oxygenated, it returns to the left atrium and then moves to the left ventricle.
4. From the left ventricle it is pumped to the rest of the body. 5. After circulating through the body it is returned to the right atrium.
Heartbeat • Heart beats because: when ventricles contract they pump blood at a high
pressure into the arteries, causing the walls to stretch and create a pulse. • Measure a pulse in our wrists, temple or neck, by every time an artery
stretches and crosses an area of bone close to the surface • Experiment: When we exercise our pulse rate is higher this is because: -‐ The muscles use more energy -‐ To get this energy the muscle cells must burn more glucose using oxygen -‐ To do this the blood must flow faster, thus the heart must pump faster. • When listening through a stethoscope we hear: -‐ Lub noise: valves closing between the atria and ventricles -‐ Dub noise: valves in the arteries closing • The contractions of the heart are controlled by electronic impulses. • These impulses are measured by an electrocardiograph and printed out
as electrocardiograms • Part of an electrocardiogram:
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• P wave: electrical signals make atria contract causing blood to be forced into the ventricles
• QRS wave: electrical signals makes ventricles contract and at the same time the valves between atria and ventricles close (lub) so blood can not flow back into the atria and it is pumped into the arteries
• T wave: electrical signal spreads back over the ventricles in the opposite direction causing valves between ventricles and arteries to close (dub)
• The cardiac muscle is contactable tissue that makes up the walls of the
heart • The heart beats when the cardiac muscle contracts and relaxes. • Specialized cells in the wall of the right atrium called the sinotrial node
and A/V node send out electrical impulses to make the muscle contract and relax.
Problems with heartbeat • Artificial Pacemakers can be used for life threatening abnormalities in
heart contraction rates • Tachycardia = heart beats too fast (100 beats per minute) • Bradycardia = heart beats too slow (50 beats per minute) • Cardiac arrest: heart stops pumping effectively – muscles of the ventricles
start beating fast and irregularly without pumping blood • Arrhythmia occurs when conduction of impulses from the sinotrial node
is impaired
Pacemakers • The natural pacemaker of the heart is the sinotrial node • Artificial Pacemaker: a small electrical device, implanted in the chest to
help the heart beat at a regular rhythm through electrical pulses. • There are two types of pacemakers: • Fixed rate: continually sends out electrical impulses at the same rate • Demand: sends out impulses if the heart beat is irregular • Historical developments of artificial pace makers: 1920: William Einthoven invented the electrocardiograph 1931: first artificial pacemaker 1950: external cardiac pacemaker developed 1958: first internal pacemaker: operated by a battery –needed frequent charging 1960: mercury zinc battery capable of lasting 1 – 2 years 1969: first demand-‐ pacemaker 1970: lithium iodine batteries were developed 1990-‐2007: smaller, longer lasting pacemakers
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• Advantages of technological advances for pacemakers:
Technological advance Development Advantage Long lasting batteries Implemented under the
skin No wires passing through the skin
Casing that does not corrode
No corrosion Last longer
Flexible electrical leads Leads can be pushed through blood vessels to reach the heart
No need for surgery
Biocompatible substances Implemented without rejection
No infections
Miniaturization Smaller Smaller and lighter Integrated circuits/microchips
Smaller Less effected by external radiation
Transmit and sense and store information using electromagnetic radiation
Can be calibrated by remote control
Reduces the need for further surgery
• The two main materials used in pacemakers are:
-‐ Titanium alloys: biocompatible, corrosion resistant, low density, non –toxic, smooth, flexible
-‐ Polymers: biocompatible, corrosion resistant, low density, non –toxic, strong
Heart valves • There are four valves in heart:
1. The entry to the aorta (aortic valve) 2. The entry to the pulmonary vein (pulmonary valve) 3. The right atrium (tricuspid valve) 4. The left atrium (mitral valve)
• The function of these valves is to allow blood to flow in one direction • Faulty valves can arise from:
-‐ Damage by infection -‐ Deformed from birth
• They cause blood to flow backwards, meaning that the heart can not pump blood effectively causing tiredness and shortness of breath
• Experiment: A ping pong ball inside a funnel symbolizes a heart valve: -‐ Exhaling: ball is suspended symbolizing blood flowing forward -‐ Stop exhaling: ball covered the hole symbolizing blood being stopped to
not allow it to go backwards • There are two main types of manufactured heart valves:
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Ball in cage • The blood pushes the ball out of the way as it flows through. If the blood
try’s to flow backwards it pushes the ball against the ring sealing the space
Bileaflet valve • Opens to allow the flow of blood and then closes prevent its backflow • Less turbulence than ball in cage
Materials • There are three main materials used in artificial heart valves:
Pyrolytic carbon: durable, strong, lightweight, smooth to allow the even flow of blood to prevent clots Metal alloys: durable, strong, lightweight, corrosion resistant Teflon: durable, strong, lightweight, forms a smooth non-‐sticky surface, which allows blood to flow smoothly without, clots.
Blocked Arteries • Arteries are often blocked by plaque. • Heart arteries are Conarary arteries. • Conarary arteries supply oxygenated and nutrient filled blood to the heart
muscle • Plaque are fatty deposits the build up inside the walls of blood vessels • Plaque can cause diseases, block blood vessels, harden the artery walls
(arteriosclerosis) and weaken the walls of blood vessels = effecting the blood flow to and from the heart.
• The two main ways of unblocking arteries:
Angioplasty • This involves a thin,
flexible catheter (tube) with a balloon at its tip and a stent around it, is threaded through a blood vessel to the affected artery.
• Once in place, the balloon is inflated to compress the plaque against the artery wall.
• The catheter is then removed with the stent remaining, allowing blood flow through the artery.
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Bypass surgery • Involves getting a saphenous vein from the patient’s leg a using it to
bypass the plaque build up in the Conarary artery. • By doing this it completely diverts the direction of blood flow around the
plaque build up.
• If you have blockages in three or more coronary arteries, your doctor is likely to recommend bypass surgery. But if you have one or two blocked arteries and neither is the vital left coronary artery, you may chose either.
Heart Transplants • An artificial heart is a device that keeps the heart beating for a short
amount of time while the patient waits for a donor. • When the donor heart is transplanted a constant immune rejection
medication must be taken to combat contracting other diseases • Impact on society of heart transplants: -‐ People can live longer and have a better quality of life -‐ Because people live longer the older age will live longer and hence need
care (health care and elderly homes)
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3. The wide range of movements, continual absorption
of shocks and diseases make the skeletal system venerable to damage but new technologies are
allowing the replacement of some damaged structures
The skeleton • There are four parts of the skeletal system: -‐ Bones: The dense, semi rigid, porous, calcified connective tissue forming
the major portion of the skeleton of most vertebrates. -‐ Muscles: A tissue composed of fibers capable of contracting to effect
bodily movement: -‐ Tendons: A flexible
but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone
-‐ Ligaments: a band of fibrous tissue connecting two bones at a joint.
-‐ Cartilage: the smooth covering over the ends of joints
• Function of skeleton = provide support and shape for the body, protect internal organs and allow movement
• Diagram of the human skeleton
• Experiment: when placing chicken wings in hydrochloric acid for two days, they were taken out and were: rubbery, soft and easy to bend. This was because:
-‐ The hydrochloric acid dissolved minerals such as calcium from the bones. -‐ Since calcium makes bones hard and strong, the bones were flexible
because they lacked it
Spongy and compact bones • Compact bone provides for support, it has little ability to absorb shock.
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• Spongy bone is not as hard or strong as compact bone but it is lighter and is able to absorb shock better
Joints • Joints allow bones to move in different directions.
Synovial Joints
• Synovial joints: are a joint enclosed in a capsule and lubricated by a fluid. • Synovial joints, their location, and the type of movemnt they allow:
• Cartilage forms the layer between bones, allows a smooth movement of joints -‐ reducing friction and cushioning impact between two bones
• Synovial Fluid comes from the synovial membrane, it lubricates the joint to reduce friction
Replacing joints • The most common materials for replacing joints are:
Type of joint Locations Movement Ball and socket Shoulder, hip Circular motion Hinge Fingers, elbow knees To and from, single plan,
like a door Double hinge Thumb Side to side, to and from Sliding Spinal bones, tarsal
bones on the foot Flattened or slightly curved surfaces move across each other in two planes
Pivot Neck One bone rotates around the other
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Silicones • The properties of silicone that make it suitable for use in biomaterials
include: -‐ Flexible -‐ Elastic -‐ Insoluble -‐ Impervious -‐ Inert (acid resistant) -‐ Absorbs impact -‐ Low friction surface • Silicone would be the most suitable substitute in coating small joints in
fingers and toes • This is because it is biocompatible and is as strong and flexible as natural
joints
UHMWPE • Ultra, high, molecule, weight, polyethylene, is a polymer made from
thousands of ethylene joined together. • It is mostly used to replace cartilage in joints because:
Polyethylene Coating
• Artificial joints are coated in polyethylene because: -‐ Smoother = reducing friction -‐ Easier to compress = helps absorb impact -‐ If they weren’t coated the metal would rub against the bone and
accumulate joint problems
Superalloy’s • A superalloy is made from a mixture of metals such as: -‐ Titanium alloy -‐ Molybdenum alloy -‐ Cobalt chromium • It is suitable for the ball and stem of large joints because: -‐ High strength = to be able to support weight -‐ Low density = to feel the same as the natural joint -‐ Biocompatible = so it doesn’t react -‐ Inertness = so it doesn’t corrode or rust
Properties of UHMWPE Reasons for suitability Biocompatible Will not be rejected Similar density to living tissues Will not cause problems because it has
the same weight Durable Lasts a long time with out
replacements Low friction Reduces friction in the joint Hard, strong and resists deformity Will maintain its shape Highly elastic Stretches with joint and will absorb
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• Superalloys are much stronger than polyethylene materials such as UHMWPE but additionally have higher density and much lower flexibility.
• Therefore making them useful for different parts of an artificial joint
Implementation of artificial joints • Joints can either be cemented or un-‐cemented into place
Cemented • The cement is a chemical called ‘methyl methacrylate’ • This is mixed with a catalyst which makes the cement form long polymer
chains into the surrounding bone tissue • This makes a strong bond between the replacement and the surrounding
bone
Uncemeted • Implants that aren’t cemented are made with microscopic pores so the
body’s own tissue can grow into and around the implant to hold it in place
Advantages and Disadvantages • Cemented implants don’t last as long as uncemeted • Recovery after the operation is much quicker with cemented
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4. Life support systems can be used to sustain life during operations or while the body repairs itself
• The respiratory system is the biological system that introduces respiratory gases to the interior and performs gas exchange.
• A diagram of the respiratory system:
• The alveoli are the final branching’s of the respiratory tree (end of the bronchioles) and act as the primary gas exchange units of the lung.
• Experiment: balloons representing lungs attached by a glass tube representing the trachea, in side of a glass jar representing the chest, with rubber across the opening of the jar representing the diaphragm.
• Pulling down on the rubber: the size of the inside cavity of the chest is increased so pressure inside is less than outside air pressure, the air
Parts of respiratory system Functions Nasal passages Warm and filter air Trachea (windpipe) Carry air from throat to bronchi Larynx (voice box) Allow for speech Bronchi Carry air from trachea to lungs Alveoli Fill with inhaled air so exchange of
gases can occur Capillaries Form a network of blood vessels
around alveoli Epiglottis Prevents food entering the trachea
when we swallow
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rushes to equalize and the balloons fill up. • Pushing up on the rubber: the inside cavity of the chest is deceased, so
pressure inside is greater than outside pressure, air is pushed out and balloon empties
Cardio-‐pulmonary Resuscitation • Cardio-‐pulmonary Resuscitation (CPR) consists of two parts: -‐ EAR (expired air resuscitation): supplying air to the lungs when the
person is not breathing -‐ ECC (external cardiac compression): maintaining heartbeat by external
compression, so as to keep the blood circulating around the body • CPR can maintain life when the heart has stopped beating because
exhaled air contains some oxygen (17%) • Therefore oxygen can be supplied to lungs by expired air resuscitation • Experiment: limewater goes cloudy (milky) with inhaled air and very
cloudy with exhaled air -‐ Therefore exhaled air has more CO2 than inhaled air
Artificial lungs • When the patient has functioning lungs the artificial lung used: -‐ Is a mechanical device that forces air in and out of the lungs -‐ To ensure carbon dioxide is removed and replaced with oxygen at the
same concentration. • When the lungs are diseased or not functioning: -‐ An IMO (intravenous membrane generator) is used. -‐ This device is inserted into one of the large veins that lead into the right
atrium -‐ The blood is oxygenated and CO2 removed before the blood reaches the
heart -‐ This bypassing the lungs, allowing them to recover • The operations that would require an artificial lung are: -‐ Lung surgery
Life support systems • Life support systems is medical equipment that assists or replaces
important bodily functions, enabling a patient to live who otherwise might not survive
• Two of these include: Heart lung machine -‐ A Heart lung Machine consists of a chamber that receives the blood from
the body, which is then pumped by the machine through an oxygenator. -‐ The oxygenator removes the CO2 and adds oxygen. The pump then
pumps this newly oxygenated blood back to the body -‐ Used in Heart and lung transplants and bypass surgeries (because they
need to stop blood pumping in the heart) when a person has a very diseased heart
Kidney dialysis machine
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-‐ Is a machine, which takes over the role of the kidneys if they are damaged, diseased, or undergoing a kidney transplant.
-‐ Blood is diverted through the dialysis machine, waste such as urea is filtered from the blood and the blood is then returned to the body
5. The use of non – invasive or minimally invasive, medical techniques has greatly reduced risks to
patients and has increased our understanding of how the body works
Tools for diagnosis • There are two types of medical techniques for diagnosis:
Minimally Invasive medical techniques • Techniques that use very small incisions or have a minor effect on the
body • These include techniques such as:
Keyhole surgery (endoscopy)
• An endoscope is a tube, which can be inserted into the body through small incisions or body openings.
• Which contains optical fibers to study the inside of the body • Advantages: -‐ Endoscopes 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 (nose, mouth, anus)
• Disadvantages: -‐ Endoscopes allow only a small area to be illuminated at a time -‐ A picture of the whole diagnostic area must be built up from smaller parts -‐ Endoscopy may not detect some conditions • Used to: study areas of problems in the body, remove gall stones, to look
for cancer, look for blockages in the fallopian tubes • Impact on understanding of how the body works: -‐ Real life image of the inside of the body -‐ Therefore helping doctors understand what it looks like
Non -‐ invasive medical techniques • Techniques that investigate the human body without surgery or that do
not affect the body’s normal functioning • These include techniques such as:
X-‐ray machines
• X-‐ray machines are high frequency electromagnetic radiation, that passes through soft tissues and leaves an image of hard tissues, such as bones, on photographic film
• Advantages -‐ Quick and painless
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-‐ They help radiologists identify cracks, infections, injury, and abnormal bones.
-‐ They also help in identifying bone cancer. -‐ X-‐rays help in locating alien objects inside the bones or around them.
• Disadvantages -‐ X-‐rays makes our blood cells to have higher level of hydrogen
peroxide, which could cause cell damage. -‐ A higher risk of getting cancer from X-‐rays. -‐ The X-‐rays are able to change the base of the DNA causing a mutation.
• Used to: detect bone abnormalities and to detect breast cancer • Impact on understanding of how the body works:
-‐ For the first time doctors were albe to see inside the body without cutting it open
-‐ Allowed doctors to see bone fractures and study the healing process
Ultrasound • Ultrasound uses high frequency sound waves to form pictures of organs
inside the body, which reflect the sound waves. • Advantages:
-‐ Quick, painless and inexpensive -‐ Safe =sound waves are low energy/harmless
• Disadvantages: -‐ Ultrasound pictures are not always clear -‐ A technician is needed to conduct it
• Used to: monitor valve problems, monitor the development of embryos and to look for the presence of gall stones
• Impact on understanding of how the body works: -‐ Provided great info about the development of the human embryo -‐ Helped doctors understand the actions of heart muscles and valves
Magnetic Resonance Imaging (MRI)
• An MRI is a technique where large magnetic fields are used to obtain 3D images of the inside of the body
• Advantages: -‐ Can provide cross sectional images, building up a 3D image of the area -‐ Provides more information than x-‐rays
• Disadvantages: -‐ Affected by movement -‐ Very expensive -‐ Makes some patients feel claustrophobic
• Used to: detect spine, joint or muscle problems, detect Brain tumors and abnormalities and Heart or blood vessel problems
• Impact on understanding of how the body works: -‐ Improved understanding of the structure and functions of the body
components -‐ Increased knowledge of how the brain functions
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Chapter 3 Information systems
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1. Information systems are many and varied and depend on the transfer of
energy from place to place 1.1 Identify a range of information systems used daily
• Some information systems used daily include: -‐ Talking and listening: in person, telephone, radio and television -‐ Reading written info: in newspapers, magazines, letters -‐ Electronic: using computers and faxes
1.2 classify information systems as: Verbal and nonverbal, Short distance and long distance, Electronic and non-‐electronic
• Verbal: includes words both spoken and written (email, talking) • Non-‐verbal: no words (smoke signals, sign language) • Short distance: in person (facial expressions) • Long distance: not in person (radio) • Electronic: uses electricity to communicate (TV) • Non-‐electronic: doesn’t need electricity (photographs)
1.3 Outline the basic pattern of the information transfer process as: code common to both parties, message, transmission of coded message and decoder
• Code common to both parties -‐ Pictures, words and music are examples of codes. -‐ The sender deliberately uses agreed conventions or codes, which must
be learned, to construct a message. • Message:
-‐ A message to be transferred electronically may have to be coded again, so that it can alter the carrier current or wave in a systematic and consistent way.
-‐ The two ways of doing that are by either analog or digital means. • Transmission of coded message
-‐ Once the carrier current or wave has been coded, it is sent to the required destination.
-‐ Modern communication systems use either an electric current or electromagnetic waves to carry messages.
• Decoder -‐ Two steps are now involved in extracting the message -‐ The first detects and separates the code from the carrier current or
wave. -‐ The second involves converting that code into a form that the
receiver’s senses can detect and interpret to make meaning.
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1.4 Recall phenomena and events where different forms of energy are used • Different types of energy include: Chemical, heat, light, magnetic
electrical, kinetic, potential, solar, sound, electromagnetic and nuclear • Energy changes that occur:
Appliance Energy change Electric kettle Electrical Heat Toaster Electrical Heat and light Solar cell Solar Electrical Microwave Electrical Electromagnetic radiation and heat Torch battery Chemical Electrical Car using petrol as fuel
Chemical kinetic and heat
1.5. Gather and process first-‐hand and secondary information on the basic pattern of the information transfer process in the following systems: -‐ Land connected telephone -‐ Mobile phones -‐ Television -‐ Radios -‐ Compact Disc players To outline features that the systems have in common and use available evidence to discuss the applications of these systems Land connected telephone Info transfer process
• Sound → coded by microphone to electrical signals → transmitted through electrical cables → Speaker in receiver → Decoded to sound
Application: Communication Mobile Phones Info transfer process
• Sound → coded in microphone → transmitted via microwaves from tower to tower → detected by receiving mobile → decoded → sound.
Situation Code Transmission Decoding Talking to another person
Language Sound waves Ear and brain
Sending a fax Digital signals Electric current Printer Watching TV Language Electric current,
radio waves Aerial and TV
Listening to radio
Language Electric current, radio waves
Areal and radio speakers
Remembering the information transfer process refers to: code → message → transmission → decoder
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Application: Communication Television Info transfer process
• Sound and light → coded by camera and microphone → transmitted through electricity cables → converted to radio waves and transmitted at transmitting tower → detected by aerial → decoded by TV → sound and light pattern
Application: Entertainment Radio Info transfer process
• Sound → coded by microphone → transmitted through electricity cables → converted to radio waves → detected by aerial → decoded by radio → sound
Application: Mass entertainment Compact disc players Info transfer process
• Sound → coded by microphone → laser light → decoded by player → electrical → sound.
Application: entertainment What they all have in common
• They all involve energy transformations, coding of information, electric currents and decoding devices.
• They are all electronic, that is, they require electricity. • They are capable of transmitting information over long distances (except
compact disc player)
1.7. Gather and process information from secondary sources to develop a timeline of communication systems introduced to society and use the available evidence to analyze the impact these systems have had on society and predict possible future directions in communication technologies Communication
system Impact on society
Land connected telephones
• Long distance communication • Increased speed of communication • People could work from home
Mobile phones • People could keep in touch easier • People could call for help if they were in trouble
Television • Rapidly spread news events to people i.e. impending disasters
• Entertainment • Advertisements
Radio • Up to date news bulletins
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• Music • Two way communication i.e. talkback
Compact disc players
• Different types of music could be stored in one device • Fast access • Increased capacity to store info in a small space
Future directions in communication technology
• Decrease size = more portable • Increase in schooling/education through computers • More shopping will be done electronically rather than physically
1.8. Discuss the advantages of using a range of information systems • Some systems lend themselves better to specific applications.
-‐ For example, the coding systems used in FM radio are not destroyed by natural phenomena, such as electrical storms, during transmission.
-‐ AM radio can be transmitted over greater distances than FM radio but the signals may be interfered with by electrical storms and other nearby communication equipment.
• Access to a choice of systems is inherently more reliable. For example, international telephone calls can go via cable or satellite. If one fails, the other can take over.
• If you are an advertiser, the choice of radio, TV, print or Internet means that your message is more likely to be received and appropriately interpreted by the receiver.
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2. Electromagnetic radiation can be modulated to carry different types of
information 2.1. Identify the types of waves in the electromagnetic spectrum currently used for communication systems as: -‐ Visible light -‐ Infra-‐red -‐ Microwaves -‐ Radio waves, which include: TV, FM radio waves and AM radio waves Properties of a wave
• Waves are produced by vibrations. • They carry or transmit energy.
• A wavelength is the distance between two successive points on a wave (crests)
• The frequency is the number of waves passing a point each second, measured in hertz (Hz).
The electromagnetic spectrum
• Is a series of waves, which consist of fluctuating electric fields and which vary in frequency and wavelength
Types of waves used for communication systems are:
• Visible Light: optical fibers • Infra-‐red: laser optical fibers and remote control devices • Microwaves: satellites and mobile phones • Radio waves: TV, FM and AM radio
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2.2.Perform a first-‐hand investigation to observe ways in which waves can be modulated to carry different types of information
• Modulated waves are modified or changed. • Radio waves are modulated because:
-‐ An unmodulated wave would be very weak, with only very long aerials being able to detect them
-‐ Everyone would transmit at the same frequencies – so there could only be one radio station in each area
• The carrier wave is the basic wave being transmitted from a radio station • The modulation in AM and FM radio is different:
-‐ AM (amplitude modulation): carrier wave is modulated by adding the wavelengths of the sound wave from the microphones to the carrier wave
-‐ This then changes the amplitude of the carrier wave producing an AM signal
-‐ FM (frequency modulation): carrier wave is modulated by adding the frequency of the sound wave from the microphones to the carrier wave
-‐ This then changes the frequency of the carrier wave producing an FM signal
2.3. Compare the advantages and disadvantages of using microwaves and radio waves in communication technologies
2.4.Identify communication technologies that use energies from the electromagnetic spectrum for communication purposes
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Electromagnetic wave Communication technologies that use
these electromagnetic waves Visible light Faxes, phones, computer-‐based
communication transmit digital information at the speed of light through optical fibers in the phone line
Infra-‐red Remote control devices for TV and radio
Microwaves Land based telephone systems, satellite TV communication and mobile phones
FM radio waves TV, FM radio stations AM radio waves AM radio stations and two-‐way radios
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3. Electromagnetic waves have different properties which are utilized in a range of communication systems through air and space 3.1.Identify that where information systems cannot be physically linked the information may be transmitted in wave form through the atmosphere or space
• Communication systems that have a physical link include: landline phones and faxes
• Communication systems that don’t have a physical link are transmitted in waveform as electromagnetic radiation passes through the atmosphere or space
3.2.Identify the properties of energy from the electromagnetic spectrum that make it useful in communication technologies including its: -‐ Speed of travel -‐ Ability to travel in a straight line -‐ Ability to be reflected
3.3. Describe the individual properties of visible light, radio waves (AM, FM, TV waves) and microwaves and relate these to their use in communication systems Visible light
• Travels at the speed of light, in straight lines and can be reflected along optical fibers: so it can scan pages in fax machines and transmit digital info through optical fibers almost instantly.
Microwaves
• Travel at high speeds and can be reflected: instantaneous communication • Travels in straight lines: so the repeater stations must be in sight of each
other Radio waves (FM)
Property Application Travels at 300 000 000 ms-‐1 Information is relayed almost instantly Travels in a straight line in a uniform medium
If the medium changes, the waves will be refracted. If the medium is uniform, waves can travel directly to their target
Can be reflected Waves can be reflected off satellites and along optical fibers.
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• The audio signal changes the frequency of the carrier wave producing an FM signal: affected less by electrical interference and produce a higher quality transmission of sound.
Radio waves (AM)
• The audio signal changes the amplitude of the carrier wave producing an AM signal: allowing it have a greater range than FM
Radio waves (TV)
• A wider bandwidth than radio stations: Carry both sound and visual information
3.4. Plan choose equipment or resources for, and perform a first-‐hand investigation to compare the quality of reception of AM and FM radio waves Method
1. Set the radio at AM 2. Wrap the radio in foil. Test its signal. Test it with no foil 3. Set the radio to FM. Repeat step 2 4. Record results
Variables Independent: AM and FM radio waves Dependent: quality of reception as measured by the range of frequencies detected by a cathode ray oscilloscope. Results Quality of reception (loudness) Radio station Wrapped in foil Not wrapped in foil AM 954 kHz Soft Loud AM 1170 kHz Soft Loud FM 104.1 kHz Loud Loud FM 96.9 kHz Loud Loud Conclusion AM Amplitude
changes when audio signal added
AM greater range than FM (longer wavelength)
Lots of interference from electrical appliances
FM Frequency changes when audio signal added
FM usually narrow range (shorter wavelength)
Less interferences (electrical appliances use frequencies closer to AM)
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4. Geostationary satellites relay and transmit information from the other side of the world 4.1. Gather, process and analyze information from secondary sources to identify the satellites used for ‘live’ telecast from other regions of the world to Australia and vice versa and to present reasons why communication satellites have different aerials and positional orbits
• A satellite is an object that moves around the planet in a circular or elliptical path (this path is called an orbit)
• Four functions of satellites: 1. Communication 2. Prediction of weather 3. To obtain military info 4. Monitoring the environment in scientific research
• The first use of satellites: in 1962, Telstar, was put in orbit to transmit telephone calls and transatlantic TV broadcasts
• The speed of the satellite being placed in orbit is important = the speed must be correct for their altitude so it can stay in orbit.
• For AUS, satellites are used for live telecasts and telephone calls from other regions of the world.
• Uplink: info transmitted to the satellite from earth Downlink: a signal which has been collected, boosted, had its frequency changed and sent to earth
• Satellites absorb energy from the sun by solar panels which store it as chemical energy for during the night
• Satellite footprint = area it can send and receive messages • Satellites have different aerials and positional orbits because:
-‐ Aerials: because they use different frequencies to transmit and receive on
-‐ Positional orbits: low: below
Type of satellite orbit
Typical altitude (Km)
Satellite use
High earth orbit
36 000 • TV and telephone transmission • Provides continuous contact for an area
Medium earth orbit
10 000 • Land images • Weather forecasts • Telephone communication (changes to
different satellites as one moves out of range
Low earth orbit 1000 High altitude, artic + Antarctic communication
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4.3.Explain why the satellite must be at a height where its revolution period is the same as that of the Earth’s period of rotation
• A geostationary satellite is a special geosynchronous satellite, and is one that orbits the Earth at the same period as the period of rotation of the Earth so that its position in the sky relative to any position on Earth is always the same
• An object in such an orbit has an orbital period equal to the Earth's rotational period (one sidereal day), and thus appears motionless, at a fixed position in the sky, to ground observers
• Thus, if they are travelling with exactly the correct speed they never actually get any closer to the Earth’s surface.
• Tracking stations on Earth use radio signals to activate small rockets on the satellite to keep them in the correct orbit.
4.2. Explain why an Earth-‐based satellite dish must always face the geostationary satellite communicating with it
• The receiving dish on earth must be large as the signal is relatively weak -‐
-‐ due to the satellite dish being quite distant at approximately 36,000 km. • As a result of this the satellite dish must face the same direction at all
times to ensure that signals are received and retransmitted in the correct directions to the intended receivers.
• These satellites are used for communication because they always have the same line of sight access to a specific region of the earth
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5. Information can be transmitted in the form of electrical impulses
5.1. Gather, process, analyze and present information from secondary sources to identify energy transfers involved in coding and decoding information by digital technologies.
• There are two types of info systems: -‐ Analog: info is transmitted as a wave -‐ Digital: info is transmitted as numbers
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• Digital technology uses pulsed electrical or electromagnetic signals as the transmitting code. -‐ For example, computer based technology is coded into a series of
zeros and ones (binary) • Energy is transferred in computer dial up internet through the telephone
line, the receiving computer modem changes the analog electrical signal back to a digital electrical system
• Energy is transferred in optical fibers by the message being sent as a series of digital energy pulses, which are then changed to digital electrical pulses and analog electrical signals
5.2. Identify communication technologies that transform one type of energy into electrical energy
• Some examples of communication technologies that transform different types of energy into electrical energy are:
5.3. Describe the transmission of images using digital technologies in terms of scanning of the input image along very thin lines
• Info is copied in a fax machine: -‐ The page is read a series of very fine lines. -‐ Laser light is shone onto the page in very thin lines and light reflected
from each point is detected. -‐ The reflection or absorption of light at each point is recorded as a
digital electrical signal by the fax machine.
• This image is transmitted by: -‐ The reflected light is converted to electrical signals.
-‐ The input digital signal is transmitted through the landline telephone -‐ It is received by the targeted fax machine as a digital electrical signal -‐ Using a printer, this receiving machine converts the digital signal back
to an image on a page
5.4. Explain how the coding of the image into a series of zeros and ones allows its transmission and ultimate decoding
• Binary code is a number system that uses only zeros and ones to represent any number
• For example the number 10 is: 1010
Communication Technology Type of energy transformed into electricity
Microphone, telephone, radio, TV, music
Sound
Faxes, bar codes, CD’s, DVD’s, TV camera
Light
Electric keyboard Kinetic
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Because: 16 – 8 – 4 – 2 – 1 8 + 2 = 10 and the number one in each code represents a number that ha been used, any that haven’t been used are kept as zeros
• Electronic digital devices work by digitizing an image, i.e. dividing it into a
grid of dots. -‐ Each dot is either on or off, depending on whether it is black or white. -‐ Electronically, each dot is represented by a bit that has a value of
either 0 (off), or 1 (on). -‐ In this way, the device translates a picture into a series of zeros and
ones (called a bit map) that can be transmitted like normal computer data.
-‐ On the receiving side, a device reads the incoming data, translates the zeros and ones back into dots, and reprints the image.
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6. Electrical energy can be converted to light energy for use in optical fiber
communication systems 6.1.Perform a first-‐hand investigation to demonstrate the transmission of light through an optic fiber
• We had a light with optical fibers connected to it, when the lights shone through we were able to see the pinpoint of light.
• This showed how small they are, as well as how light can be transmitted through a piece of fiber
6.2.Outline properties of optical fibers as communication carriers
• An optical fiber is a thin strand of material, that allows light to be passed through it.
• An optical fiber cable is may optical fibers, each with its own cladding, embedded in insulating material and coated with plastic to form a single cable
• The glass in optical fibers is made so that light is unable to emerge side ways from the glass.
• This is achieved by covering the glass with a cladding of denser glass or plastic.
• As light travels from the inner glass core to the denser cladding, it bends so much that, instead of leaving the glass, it is reflected back into it -‐ this process is known as total internal reflection.
• Properties of optical fibers that make it relevant as communication carriers: -‐ Transparent to light
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-‐ Cheap -‐ Tough -‐ Flexible -‐ Easy to install even a over long distances -‐ Durable -‐ Non-‐corrosive
• However if a fiber is damaged it is very difficult to fix
6.3.Outline the principle of total internal reflection and relate this to the advantages of fiber optics over more conventional carriers of information
• Total internal reflection occurs when: -‐ Light travelling from a more dense to a less-‐dense medium hits the
boundary between them. -‐ Some degree of reflection back into the denser medium (internal
reflection) always accompanies refraction. -‐ When the angle of incidence is greater than the critical angle, total
internal reflection occurs, i.e. all the light is internally reflected. • Optical fibers, using laser-‐generated light, can transmit many more
messages at one time than coaxial cable or microwaves. • The pulses of light are produced millions of times per second and pass
along the optical fiber being reflected from the walls several thousand times per meter.
• Glass and plastic fibers as thin as a few micrometers in diameter can be used to transmit light with very little loss of intensity.
• Even if the fibers are bent the critical angle is rarely exceeded and the signal will be transmitted.
6.4. Outline the differences and the relative merits in the use of fiber optic cables and metal cables to transmit and receive information
• The advantages of optical fibers over metal and coaxial cables are: -‐ Have a much greater bandwidth than metal cables. This means that
they can carry more data per second, e.g. can transmit several gigabytes of data per second.
-‐ Are not affected by radio waves, so there is no static -‐ Are much thinner and lighter than metal wires -‐ Are less susceptible to corrosion than metal cables -‐ Can handle digitally coded light (the natural form for computer data),
as well as analog signals -‐ Can multiplex thousands of voice channels together over a single
optical fiber -‐ More secure, as information cannot be intercepted easily.
• The disadvantages of optical fibers are: -‐ The main disadvantage of fiber optics is that the cables are expensive
to install. -‐ They are more fragile than wire and must be spliced together
precisely and carefully.
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-‐ Repeaters need to be added every 55-‐65 kilometers to boost the signal strength.
• Telephone companies are steadily replacing traditional metallic telephone lines with fiber optic cables.
6.5. Process and analyze information from secondary sources to compare and contrast copper cables with fiber optic cables in relation to: -‐ Carrying capacity -‐ Cost -‐ Rate of information transfer -‐ Security Property Copper cables Fibre-‐optic cables Carry capacity • Carry less info • Carry enormous
amounts of info several GB’s per second
• Lots of messages can travel at once (multiplexing)
Cost • Similar costs at present to manufacture cables
• Cost of copper expected to rise as it becomes rarer
• Price of fibres should fall
• Fewer repeaters needed (so less costs)
• Overall cost is less (and decreasing)
Rate of info transfer • Electrons travel more slowly along copper cable
• Faster it uses visible or infra red light which travels at a speed of 300000000 m s-‐1
Security • Relatively easy to tap info
• More secure almost impossible tap into info as cables cannot be split and rejoined
• Info is transmitted more precisely – there is less distortion and loss of info
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Chapter 3 Disasters
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1. Disasters may be natural or caused by human activity
1.1. Identify disasters as events associated with large-‐scale environmental or structural damage and/or loss of life
• Disaster = an unfortunate event that involves large – scale environmental or structural damage. It may not involve loss of life
1.a. Gather and process information from first-‐hand and secondary sources to identify insurance compensation for natural disasters to discuss the definitions and terminology used in insurance contracts
Insurance Term Meaning Home Fully enclosed, used for domestic
purposes, can be locked up Fixtures Permanently attached or fixed to the
home Contents Not permanently attached to home. Fittings Any item that can be removed without
damaging the home Specified items Contents that are listed separately i.e.
jewellery Collectables Have to be insured separately i.e. CD’s Replacement valve The cost to rebuild on the site at todays
prices Sum insured Amount of insurance cover purchased
for the home
1.2. Identify a range of natural disasters, with the aid of specific Australian examples Type of natural disaster Aus example Info Bushfire Ash Wednesday fires in
Vic and SA 1983. • The highest
recorded bushfire death toll ever in Australia (period).
• Killed 72 people, and destroyed more than 2000 homes
Drought Droughts in parts of south-‐eastern Australia 2003 to 2007 and still ongoing in many areas.
• Farmers were worried because lack of rain can quickly lead to destruction of
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crops, food and water running out and stock dying.
Cyclone Cyclone Tracy in Darwin 1974
• Hundreds of millions dollars of damage to buildings
• 49 people killed Hailstorm Sydney hailstorm, 1999 • Most costly Aus
disaster but no lives lost
• 1.5 billion dollars of damage
Earthquakes Newcastle earthquake, 1989
• 5.5 on the Richter scale
• 14 people killed
1.3. Identify a range of disasters associated with human activity using specific Australian examples Type of disaster associated with human activity
Aus example Info
Landslide Thredbo, 1997 • The road, above the lodge that slid down, appears not to have been maintained properly.
• 18 people died Transport accidents Glenbrook train crash,
1999 • Inadequate
training of personnel, unclear procedures, with greater priority being given to 'on-‐time running' than safety.
Salinity Salinity in the Murray Valley
• Caused by over watering by irrigators, resulting the raising of the water table that contains saline water.
Bridge collapse Derwent River in • A ship hit a pylon
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Tasmania in 1975 of the bridge, causing one span to collapse.
• Twelve people died
1.4. Identify specific Australian examples where nature and human activity have combined to produce disasters such as dust storms, shipwrecks, landslides and accidents
• An activity may have been well planned or carried out but a change in conditions could cause a disaster.
• Examples of this are: Dust storm in Melbourne in 1983
-‐ Resulted from a change in conditions. -‐ The farmland around Melbourne had been farmed and managed well. -‐ After a dry period, a freak storm built up which carried millions of tones
of topsoil off the farms into the centre of Melbourne. -‐ It caused damage in the city.
Floods in Illawara in 1998
-‐ In cities, flooding can occur if the drainage systems built by people cannot cope with the storm water.
• Disasters associated with human activity can be caused by: -‐ Equipment breaking down -‐ Poor maintenance leading to equipment failure -‐ People not following instructions or regulations properly -‐ Communication systems failing.
1.b. Gather, process and analyse information from secondary sources to create a database of natural disasters that have occurred within Australia since 1970 to include: when it occurred, where it occurred, consequences of the disaster, techniques employed to reduce the ���incidence of damage next time, techniques employed to monitor ���disaster in the future. When it occurred: Cyclone Larry march 2006 Where it occurred: QLD around the Innisfail area Consequences of disaster: Thousands of home and businesses destroyed and banana crops wiped out Techniques employed to reduce the incidence of damage next time: improving warning systems and building structure that will withstand cyclones Techniques employed to monitor disaster in the future: Satellite observations of emerging weather patterns and analysis of data obtained and analysis of evacuation plans to improve them
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2. Technological developments have improved our ability to monitor and
predict weather patterns 2.1. Define the term ‘atmospheric pressure’ and describe the movement of air currents between areas of high and low pressure
• Atmospheric pressure is the force per unit area due to the weight of the atmosphere (a layer of gases).
• These gases are kept in place by the force of gravity. • The pressure of the atmosphere is measured in hectopascals. (1
hectopascal = 100 Pascals 1 Pascal is a unit of pressure equal to one Newton per square meter)
• Air moves from a place with high air pressure to a place with low air pressure -‐ This movement of air is what we notice as a breeze or wind.
• On a weather map the air pressure in different places is shown by lines, called isobars, drawn through points with the same air pressure.
• High pressure system = air movies anticlockwise, hectopascals increase towards the centre
• Low pressure system = air move clockwise, hectopascals decrease towards the centre
2.2. Identify that the distance between isobars on a weather map indicates the relative change of atmospheric pressure in an area
• Isobars close together places that are not far apart experience a large difference in air pressure. As a result, the winds in this region will be strong.
• Isobars far apart the difference in air pressure between two places is not very large. As a result, the winds will be quite gentle.
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2.b. Gather secondary information and use the available evidence to compare changes in the relative air pressure in an area over time and relate changes to changing weather patterns
• Map indicates for Sydney: -‐ Light winds: isobars are far apart -‐ SE/NE winds: the high-‐pressure system off the coast insinuates
anticlockwise winds around the centre of the system. With winds coming from the southwest and then north east directions
-‐ Some showers: diagonal lines represent patches of rainfall. And the south west winds will bring moisture laden air from the ocean which may cause some showers
2.3. Describe the relative pressures involved in the formation of tropical cyclones and tornadoes
2.c. Perform an investigation using second-‐hand data and use the available evidence to trace the movement of a tropical cyclone
• Tropical cyclone Larry occurred in northern QLD in 2006 -‐ Originated: The coral sea off the coast of QLD -‐ Date classified as a cyclone: 4am March 18th -‐ Where it crossed the Aus coast: Innisfail, QLD -‐ Path of the tropical cyclone:
Cyclones Tornadoes
Cause Warm, moist air is rising and more air id being drawn in to replace it. This causes the air pressure at the surface to drop
Fast moving, cold, dry air moves across warm air. The warm air tries to move upwards quickly, causing a tall, twisting column of air
Pressure at the centre Low Low
Where they from Over oceans near equator
Over a small area of land
Winds Strong winds blow in a spiral pattern
Strong winds blow in a spiral pattern
Associated weather Heavy rain, floods, huge seas and storm surges
Usually rain, hail and violent winds
Time it lasts Days to several weeks 10 – 15 minutes
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2.4. Describe technological advances that have contributed to increased understanding of meteorology
• Meteorology is the study of the weather and climate. • To predict the weather, meteorologists need to measure quantities like: -‐ Air pressure -‐ Humidity -‐ Temperature -‐ Wind speed and direction. • These measurements have to be carried out not just in one place, but over
the whole country. • The basic tools for measuring these characteristics include: -‐ Thermometer for temperature -‐ Barometer for air pressure -‐ Anemometer for wind speed -‐ Hygrometer (or wet and dry bulb thermometer) for humidity. • The methods for measuring characteristics of the weather (and their
accuracy) have improved thanks to electronics and computers: -‐ Data logging equipment allows unstaffed stations to carry out
measurements at regular intervals 24 hours per day. This data can then be retrieved when needed. As a result, 'weather stations' may be placed in the most inhospitable places and left to record information without a person to run it.
• Satellites orbit the Earth and make measurements of the atmosphere.
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This includes simply taking photographs to show cloud movement as well as remote sensing technology to measure other characteristics of the atmosphere.
2.5. Describe the relationship between the monitoring of weather patterns by radar and laser light and the analysis of reflected wave patterns by computers
• Radar uses radio waves it excels at piercing bad weather, but it needs raindrops, hail or snow to get a signal.
• Lidar uses laser light it struggles to go through thick clouds or heavy rain, but it can get you wind (measurements) in clear air, because it relies on aerosols.
• From the collection of this data, wind speed and direction can be determined over large areas.
• Lidar’s higher frequency radiation will be reflected by smaller particles than lower frequency radiation of radar, allowing it to determine wind characteristics in clear conditions.
2.6. Explain why satellite photographs of cloud patterns have improved the reliability of interpretations of weather regularities and knowledge of global weather patterns
• Full-‐earth images of satellites help Australian weather forecasters trace the life cycle of weather systems, particularly those approaching from surrounding oceans.
• Satellites provide Australian forecasters with better data about air pressure, cloud patterns and solar radiation estimates.
• With this info scientists are able to predict more accurately their behaviour in the future
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3. Even with current technology, disasters such as earthquakes and bushfires are not easy to predict
3.1. Outline differences in P, S and L energy waves produced by an earthquake
• An earthquake is a movement in the Earth's crust. -‐ The crust is made up of a number of plates, which float on the material
beneath. -‐ While the continents feel like 'solid ground' they are in fact rafts that are
afloat. -‐ As the plates move into different positions, they cause tremors or
earthquakes. • An earthquake produces a number of waves in the earth's crust. There are
three types, P, S and L waves: -‐ P (Primary) waves: are compression waves they travel fastest and
can travel through both liquids and solids. -‐ S (Secondary) waves are transverse waves they travel slower than
the P waves and cat go through liquid. -‐ L waves are the slowest waves they are surface waves, which travel
along the surface of the crust as a ripple. They cause most of the damage. P waves S waves L waves Where they travel Through the body
of the earth Through the body of the earth
Along the surface of the earth
Relative speed Fast-‐ 8 km/h 4.5 km/h 3.2 km/h Type of wave Compression Transverse Transverse
• Compression: • Transverse: ↓↑
3.2. Identify energy transfers and transformations involved in L waves as they travel along the earth’s crust
• Potential energy in rocks kinetic energy in rock vibrations • Kinetic energy of rocks kinetic energy of buildings swaying and
vibrating
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3.a. Gather and process information from secondary sources on the use of: seismographs, Richter scale and Mercalli scale to record and monitor earthquakes
• Seismograph = produces a picture called a seismogram which represents the movement of the Earth's crust at the observation station.
-‐ Richter scale = rates earthquakes on the magnitude of the energy released Determined by the amplitude of the waves from the seismogram
• Mercalli Scale = subjective measure of the intensity of an earthquake based on the effects as observed by onlookers
3.3. Explain how the difference in time of arrival of P and S waves can be used to locate an earthquake epicentre
• The P-‐S time is the amount of time that passed between the arrival of the P-‐waves and the arrival of the S-‐waves.
• The speed of the two waves is well known and so the P-‐S time can be used to calculate how far the centre of the earthquake was from the observatory
• Time = Distance/ Speed
3.4. Describe the difficulties of monitoring and predicting earthquakes
• They happen deep underground, usually impossible to reach with measuring equipment.
• We cannot get measuring equipment into the right place so predicting exactly where and when they will occur is almost impossible
• Furthermore, the earthquake may be so severe that it will actually destroy the equipment set up to measure it.
3.5. Identify some of the conditions that can combine to trigger a bushfire, including dry weather, high temperatures and flammable vegetation
• Conditions that trigger a bushfire: 1) Dry weather 2) High temperatures 3) Flammable vegetation
• Conditions in our country can produce situations where all three requirements for fire are abundant:
-‐ Periods of hot dry weather can leave plants dead and dry -‐ Materials left in and around homes provide a fuel source. -‐ Hot weather is often associated with strong winds. This wind provides a
great oxygen supply for the fire and can carry sparks, starting new fires in other places.
-‐ Many of our native trees and shrubs contain chemicals in their sap which are very flammable.
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-‐ Some areas of our country are hilly or mountainous. A fire started at the bottom of a hill will quickly race uphill since hot air rises.
3.c. Gather, process and analyse information to identify types of native vegetation that promote the spread of bushfires
• Eucalypts: constantly shed bark and leaves which are slow to decompose, causing an accumulation of fuel. Also the leaves have oils in them which are highly flammable
• Acacias (wattles): tend to explode in a hot fire
3.d. Gather, process and analyse information on the use of natural resources to retard the progress of fire including: water and natural plants
• Plants that show resistance: kurrajong, white cedar and South African butterfly iris
• Water can be used to retard fires: -‐ Large planes can drop large volumes of water onto a fire -‐ Homes can be protected by filling gutters and drainpipes with water -‐ Water cools the combustible material below its ignition point so the
oxygen needed for combustion is not available
3.6. Describe the effect of the slope of the land and intensity of the wind on the speed of the bushfire
• The wind: -‐ Supplies oxygen for the fire -‐ Blows the fire across the landscape. • The landscape can be flat or hilly. A hilly landscape is more
dangerous: -‐ It makes access for fire fighters more difficult -‐ Hot air rises so that the heat from a fire at the foot of a gorge will rise and
dry out vegetation higher up possibly igniting it. -‐ Fires, which have reached the top of a ridge, can 'jump' from one ridge to
the next, sometimes hundreds of metres away, as sparks are carried across by wind
3.e. Gather, process and analyse secondary information to identify precautions that can be taken to minimise the likelihood of damage by bushfire including the removal of flammable material and shrubs
• Precautions that can be taken: -‐ Fire resistant building materials -‐ Have a source of water available -‐ Clearing gutters of shrubs -‐ Back burning when weather conditions are favorable -‐ Clearing land to produce firebreaks -‐ Early detection: lookout towers, infra red photog, satellite remote sensing
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3.f. Perform an investigation to compare the flammability of dry and fresh leaves
• Dry vegetation is more flammable than fresh vegetation as it ignites quicker
3.7. Identify and describe some of the energy transfers and transformations associated with bushfires
• Plant matter burns: chemical energy heat and light energy • Hot air moves upwards: chemical energy of plants kinetic energy of air
3.8. Discuss the reduction of fuel by controlled burns and backburns in reducing the risk of bushfires
• There are two ways in which fire fighters fight fire with fire: 1) A controlled burn
• Should only be done on days of little or no wind • is lit in an area where natural growth has produced plant material which
may become a fire risk in hot weather when it has dried out. • The job of the fire is to burn up all the plant material which may pose a
risk in summer so that there will be less fuel around when summer comes.
2) A back burn
• Is intended to help put out a bushfire • Is lit to make the bushfire run out of fuel faster. • Is lit in front of the bushfire as the bushfire burns. • A back burn is successful if it is lit close enough to the main fire so that, as
the main fire approaches, the wind it generates draws the flames and heat of the backfire into itself
• This will then mean that, as the main fire and back burn join together, the fires run out of fuel and can be brought under control.
3.g. Gather and process information to explain what steps should be taken if caught in a bushfire If you are driving a car
• Stay in your car • Pull over to the side of the road • Stop the car and turn off the engine • Wind up all the windows and close all the vents • Keep down lo • Use blankets or towels to cover up exposed skin • Sound the horn at intervals
If you are in the bush
• Seek shelter: creek bed, behind a rock
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• If you have time remove as much fuel from around you • Stay low to the ground = hot air rises • Cover all exposed skin • Don’t try to outrun it = the fire is faster • Don’t go uphill = fires travel faster uphill
If you are at home
• Stay in the house = protect yourself from the high radiant heat levels and flames
• Close windows and vents = prevent embers entering the house • Close heavy curtains and shutters = restrict the entry of heat • Turn off all electricity and gas = prevent explosions • Move furniture to the centre of the room = reduce the risk of it catching a
light • Wet the roof, walls, garden and lawns = reduce the risk of spot fires
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4. Warning devices can also be used to detect disasters associated with
human activity 4.1. Describe the energy transformations involved in the operation of a range of commonplace warning and protection devices, including: smoke detectors, fire alarms and sprinkler systems Smoke detectors
• Atomic energy kinetic energy of alpha particles kinetic energy of electrons electrical energy sound energy
Fire Alarms
• The sprinkler system detector senses the change in heat or light energy electrical energy kinetic energy of bell sound energy
Sprinkler systems
• Heat or light energy of fire electrical energy kinetic energy of running water
4.a. Analyse information and use available evidence to identify appropriate locations for smoke and fire detectors in a workplace
• Located on the ceiling away from any kitchens or bathrooms and near areas of high fire risk. E.g. near fuels
4.c. Plan, choose equipment or resources for, and perform a first-‐hand investigation to construct a working alarm or safety device
• A fire alarm has a bimetallic strip inside of it. • A bimetallic strip is two flat pieces of metal glued together. When the strip
is heated, each metal expands at a different rate causing the metal to bend so it makes contact and completes the circuit ringing the bell.
• As it cools down the bimetallic strip will straiten back out, stopping the bell
• Gold rod = bimetallic strip. Red circle = bell. Blue box = will hit the bell when the circuit is closed
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4.d. Gather information from secondary sources to identify evacuation drill procedures and assess their appropriateness in an emergency situation Evacuation drill procedure Essential Features An alarm such as continuously ringing bell
• This must be clearly audible and recognised
Escape routes • Must be simple, easy to follow and remember, clearly marked and there must be alternatives available in case of blockages
Meeting place • Must be safe, central, known to all people, able to be safely reached by everyone, be away from high risk areas and be accessible
• Must be a list of all people and a designated role caller
Practice drills • Should be held at regular intervals with everyone participating
First aid • Designated first aid people must ensure that there is equipment available at the meeting place
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5. Emergency services also assist in the prevention or minimization of
disasters 5.1. Identify the role of and account for the need for coordinated help services in times of potential disaster including: police, fire brigade, ambulance, State Emergency Service, Rural Fire Service and community organisations
• The coordination of essential services in times of potential disaster is important because:
-‐ It ensures that the maximum use can be made of each service and they don’t overlap
-‐ Helps ensure a rapid and effective response to as many people as possible
Service Roles Police • Providing specialist rescue
services • Crowd and traffic control
Fire Brigade • Putting out fires • Preventing fires • Land based rescue services
Ambulance • Directs medical operations • Treating injured people • Transporting the injured to
hospital State emergency service (SES) • Organising flood and storm
relief • Search and rescue options • Temporary repairs to homes to
prevent further damage Rural Fire Service • Putting out and preventing fires
in rural areas • Land based rescue services • Communication • Catering and welfare
Community Organisations • Salvos: Food supplies and temporary shelter
• Vinnie’s: Provides clothes and blankets
• Red Cross: personal/welfare info as well as medical supplies
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5.a. Gather and process information from first-‐hand and secondary sources to identify: the phone numbers for the relevant services in the local region, the disasters that each service deals with, the sequence of coordinated help involving these services Fire Brigade
• Phone call (000) closest brigade to the incident is notified fire engine(s) sent to the site.
• Land based rescue services and preventing and putting out fires
5.2. Assess impacts of technological developments on the warning that can be provided about impending disasters
• Some technological developments help provide warning of impending disasters while others help with activities during and after the disaster.
• Warning systems include: -‐ Better monitoring systems to help predict weather -‐ Earthquake dangers -‐ Flood and bushfire danger -‐ Improved communications networks using satellite systems, radio and
telephone to detect and warn people of changing conditions. • Support systems during and after disasters include: -‐ Improved infrastructure such as roads to help transport -‐ Improved paramedic facilities such as ambulance and search and rescue
services. • Technology has greatly improved the way in which society copes with
disasters by providing early warning signs. -‐ Technology has allowed warnings through early recognition of potential
hazards in weather conditions, flooding, and even volcanic activity -‐ These early warnings rely on availability of broadcasting techniques such
as radio and television.
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