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1. Diversity:
Chapter 5
Exploring
Materials
By Ms Agnes

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Contents
1. What are Materials
2. Classification of Materials
3. TypesofMaterials
4. Properties ofMaterials
5. Choosingthe RightMaterials for Objects

3. What are Materials
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• Materials are thingsthatare usedtomakeobjects.
• All theobjects aroundus are madeof somekindof materials
• We usematerialsto buildhouses, shops, schools and othertypes of buildings
• Onetype of materialcan be usedtomakemanydifferentobjects
• e.g. glass bottles, glass bowls. glass tumblers, glass vases, mirrors etc
• Differenttypes of materialscan beused tomakethesametype of object
• e.g. A spatula can be madeof metal,wood or plastic
• A combination of differentmaterialscan be usedtomakea singleobject
• e.g. A fanwhich is madeof plastic andmetal
• Differentmaterials have differentproperties. Theseproperties helpus decide
which materialis suitabletomakeanobject.
• We willstudy about theclassification of materials,differenttypes of materials,
theirproperties andchoosingtheright materialsto makeobjects

4.  Natural
• Materialsfrom Plants:Wood, Rubber,
*Fabrics(Cotton, Linen)
• Materialsfrom Animals:*Fabrics
(Leather, Wool, Silk)
• Materialsfrom Ground: Metal,Rock
 Man-made
• Materialsmade by Man:
Plastic,*Fabrics (Nylon, Polyester),
**Glass,**Ceramic,
*Fabricscanbeboth natural orman-made
**Although glass andceramic areman-made
materials, the raw materials used to make
them arenatural. Glass madefrom sand while
ceramicmadefrom clay that arefound
naturally
Classification ofMaterials
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• Materialscomes from various sources and canbe naturalor man-made
• Naturalmaterials are materialsthat comes from plants, animalsandground
• Man-madematerials arematerials obtained from naturalmaterialsand made through chemical
processes artificially.

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Natural Materials
Materials that come from plants, animals and ground
Fabric: Cotton
(cotton plant)
Rock
Fabric: Leather (cow)
Fabric: Wool (sheep)
Wood (trees)
Metal
Plants Animals Ground
Rubber
(rubber tree’s latex)
Fabric: Silk (silkworm)

6. Objects madefromNatural Materials
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Sources Natural Materials Uses/Objects
Plants Wood chair, table, cupboard, paper
Rubber balloon, tyre, glove, eraser
Fabrics Cotton shirt, towel, scarf, curtains
Animals
Fabrics
Leather handbag, belt, shoes, wallet
Wool sweater, blanket, cardigans
Silk dress, nightgown, neckties
Ground Metal spoon, kettle, jewellery,
electrical appliances
Rock (e.g clay and sand) house, road, bridge, wall

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Man-made Materials
Materials obtained from natural materials and made through
chemical processes artificially
bottle
Plastic Glass Ceramic Fabrics
chair
cup
windows
bowl
flower vase
swimwear (nylon)
Dri-FIT shirt (polyester)

8. Objects made from Man-made Materials
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Man-made Materials Sources Uses/Objects
Plastic petroleum bottle, chair, containers,
straws, bags
Glass sand, lime, soda cup, fish tank, windows,
mirrors, spectacle lens
Ceramics clay bowl, vase, flower pot,
teapot, walls and floor tiles
Fabrics Nylon coal, air, water swimwear, stockings, socks
toothbrush bristles
Polyester petroleum Dri-FIT shirt, pants, jackets
windbreakers, tote bags

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Types ofMaterials
• We are goingto study the differenttypes ofmaterials, their sources,
properties,disadvantages, uses and examplesindetails
• We willbefocusingon7 groupsofmaterials
1. Metals
2. Wood
3. Glass
4. Ceramics
5. Rubber
6. Fabrics(cotton,linen,leather, wool,silk,nylon, polyester)
7. Plastics

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1. Metals
Source
• Metalsarenaturalmaterialsthatcomesfrom
ground
• They exitsin theformofores withother
mineralson Earthwhich areseparatedto
obtainpure metal
• Therearemanydifferenttypesofmetalssuch
asiron, nickel,silver andgoldintheEarth’s
crust
Disadvantages
• Corrode (rust) easily
• Metalsarelimitedresources
• Weneedtoconserve metalby recycling
Properties
• Have shiny surface
• Malleable(can beeasilyhammered)
• Ductile(canbe pulled,stretchedandpressed
intosheetsandmadeintowires)
• Hard,stiffandstrong
• Can besoftandflexiblewhenthinandflat
• Goodconductors ofheatandelectricity
• Opaque(do notallow lighttopassthrough)
• Waterproof
• Sink inwater

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Uses
• Metalshave awide variety of usessuchas inbuildings, coins,
jewellery,kitchenware, electricalappliances and vehiclesbodies
• Some metals are soft andrust easily whenthey are pure, for
example, pure iron isvery soft and rust easily
• Tochangethisproperty of pure metal, a smallamountof other
metals or non-metals are added to it. Thenew metalis calledan
alloy.
• Alloysare strong hard and do not corrode easily
• Some examples ofalloys are brass, bronze andsteel
• Metals are used to makemagnets

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Examples
Aluminum Copper Iron and Steel Gold and Silver
• Coins
• Jewellery
• Ornaments
• Trophies
• Plaques
• Electrical
wires
• Alloys
e.g bronze and
brass
• Aircraft bodies
• Vehicles’ bodies
(car, train,buses)
• Cookingpots
• Kitchenfoil
• Drinks and food
cans
• Electrical
appliances
• Nails
• Kitchenware
• Cutlery
• Rods
• Pipes

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2. Wood
Source
• Wood is naturalmaterialwhich comes
from trunks,stemsand roots of trees
• Wood is thehard substancesfound
insidethebark in trunksandthick
branches of trees
• Good wood is obtainedfrom pine,teak,
oak androse wood
Disadvantages
• Can beeasily destroyed by fungiand
termites
• Catchesfire easily
Properties
• Light,strongandhard
• Durable(long-lasting)
• Can becut easily andmadeintodifferent
shapes
• Float on water
• Poor conductor of heatandelectricity
• Opaque(does not allowlight topass
through)
• Not waterproof (absorbs water)
• Somewood are soft whilesome are hard

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Uses
• Wood are usetomakehouses,buildings,hutsand furniture
• Somespecial wood are usetomakemusical instrumentssuch as violins, piano and
guitars
• Hard wood is used tomakehouses,boats andferries
• Soft woods such as wood pulp is usedtomakepaper
• We usepaper tomakebooks, envelopes, disposable cups and paper plates
• Paperis anothermaterialwhich has its own properties differentfrom wood
Examples
house table stool guitar

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3. Glass
Source
• Glassis man-made material
• It ismade upof a mixtureof
sand(foundnaturally),lime and
sodawhichare naturalmaterials
andheatedtovery high
temperature
Disadvantages
• Glassis easilybroken
• It isnot flexible
Properties
• Can betransparent (allow alllightto
pass through)or translucent(allow
somelight topass through)
• Brittle(breaks easily)
• Poor conductor of heatand
electricity
• Does notcorrode (does not rust)
• Rigidand stiff(not flexible)
• Can bemouldedintoshapes
• Waterproof (does not absorb water)

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Uses
• Glassis usedto make glassware/kitchenwaresuchas plates,cups andbowls
• It isuse tomake laboratoryapparatus,lenses,medicine bottles,vases,
ornaments, windowpanes,lightbulbs,mirrors
Examples
cup light bulb laboratory
apparatus
mirror

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4. Ceramics
Source
• Ceramics are man-made materials
• They are made from clay(found
naturally)andother non-metallic
solidsby heatingathigh
temperature tohardenit
Disadvantages
• Breaks easily
• Heavy
Properties
• Strongandhard
• Brittle
• Do notcorrode(does notrust)
• Poor conductor ofelectricity(do
notconductelectricity)
• Poor conductor ofheat(some
ceramicsare usedfor cooking)
• Canbe mouldedintoshapes
before beingfiredinovens
• Opaque (nolightpassthrough)
• Waterproof

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Uses
• Ceramics are used tomake ceramic tiles(floor tilesandwalltiles)
• They are used tomake vases, pots,mugs, plates,cups, andfoodcontainers,
decorativepieces, bricks, flowerpots, claypotandteapot
Examples
bowl vase teapot floor tiles

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5.Rubber
Source
• Rubber is naturalmaterialfrom plant
• Rubber comes fromlatex(a milkyliquid
(sap)) obtainedfromrubber trees
• Thelatexis processed toobtain different
types of rubber
Disadvantages
• Rubber is soft andeasily damagedby
heat
• It produces poisonous gases whenburnt
Properties
• Elasticandflexible
• Tough
• Durable(long-lasting)andableto
withstandwear and tear
• Waterproof
• Opaque(no lightcan pass through)
• Poor conductor of heatandelectricity

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Uses
• Rubber is usedtomake tyres of motor-vehicles
• It isused tomake boots, solesofshoes, water hoses, erasers,elasticbands,
mattresses,gloves, balloonsandtoys
Examples
tyre water hose gloves eraser

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6.Fabrics
Source
• Fabricscanbe naturalor man-made
• Fabricscancome fromanimals,
plants,mineralsandsynthetics fibers
Disadvantages
• Fabricscatchfire easily
• They canbe easilytorn
Properties
• Softandlight
• Flexibleandrelativelystrong
• Durable
• Poor conductorsof heatand
electricity
• They canbe cutandsewneasily
• Not waterproofsoitableto absorb
dyes
• Canbe either smoothor rough
Uses
• Differentfabricsare usedto make differentclothes
• Towels,curtains,bedsheets andblanketsare made offabrics

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Examples
Fabrics
Natural
Plants
-cotton
-linen
Animals
-leather
-wool
-silk
Man-made
(artificial)
Man-madefibers
(plastics)
-nylon
-polyester

23. NaturalFabricsfrom Plants
cotton linen
• Comefromcotton plant
• Made fromthefruit thatprotects the
seeds of cotton plant
• Use tomakethreads which are woven
intocottoncloth
• Soft,flexibleandabsorbent
• Cheap,cool andcomfortable towear
• Can bewashedanddried easily
• Creases easily unlesstreatedwith
chemicals
• E.g: CottonT-shirts
• Comes from the stem of flaxplant
• Rougher texture thancotton
• Naturallinencreases easilyunless
treatedwithchemicals
• E.g Fine linenuse tomake delicate
tableclothswhilethicklinenuse to
make suitsanddresses

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wool silk
leather
• Comes from skin of animals such as
cow, pigs, snakes, crocodiles etc
• Strong and durable
• Soft and flexible
• Poor conductor of heat
• Waterproof
• Has the animal natural patterns on
it to makethe design
• Can beeasily damageby fungus
• Needs to take careto maintain
texture
• E.g wallets, belts, bags,
shoes, jackets, sofa
• Comes from fur of sheep
• Wool fibre sheared from the sheep’s
body is spun into woollen threads
• Threads areknitted or woven into
clothes
• Poor conductor of heat
• Warmand suitable for winter wear
• Soft, flexible, elastic and crease-resistant
• Will shrink if not washed carefully
• Expensive
• E.gcardigans, gloves,
blankets, sweaters, coats
• Comes from silkworms of moth
• Silkworms spins long thread of silk
around its own body to form a
cocoon
• When the cocoons areharvested,
they areplacein water, silk treads
loosen andthe farmer unwinds
them
• Soft, smooth, flexible, strong and
has attractive shine
• Cooling to wear
• Can beexpensive
• E.gscarf, neckties, nightgowns,
Chinese cheongsams, dress
NaturalFabricsfrom Animals

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Man-made Fabrics
nylon polyester
• Made fromchemicals obtainedfrom
coal, air andwater
• Flexibleandelastic
• Soft andlight
• Strongandsmooth texture
• Do notshrink
• Crease-resistant(do not needto iron)
• Waterproof, not absorbent
• E.gstockings, socks, swimsuits,clothes
• Made fromchemicals obtainedfrom
petroleum
• Stronganddurable (do not teareasily)
• Do notshrink
• Winkle-resistant(do not needtoiron)
• Waterproof, not absorbent
• Dries quickly
• E.gOuterwearsuch as parkas,
windbreakers, suits,pants, sports wear

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7. Plastic
Source
• Plasticis man-madematerial(synthetic
andartificial)
• Made frompetroleum(crude oil) and
chemicals thatcomes from fossil fuels
from underground
Disadvantages
• Easily damagedby heat
• Releaseharmfulgases intoatmosphere
whenburnt
• Non-biodegradable (cannot be
decomposed) andwill causeland
pollution
Properties
• Strongandlight
• Durable
• Water proof
• Poor conductors of heatandelectricity
• Do notcorrode(do notrust)
• Can beeasily coloured andmadeinto
shapes
• Can betransparent,translucentor
opaque
• Can beflexibleor stiff,rigid
• Can besoft or hard

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Uses
• Basedontheir texture andproperty, plasticsare used tomake a wide range of
products
• The mostimportantpropertyofplasticisits lightweightandstrength
• Comparedto other materialsofthe same size, plasticsnotonlyweigh lessbut
canalsowithstandheavyload
• They have been usedto replacemany materialslikeglass,wood, metaland
rubber
• They are use tomake foodcontainers,grocery bags, table,chairs,
compartmentinaircraftsandcars, footwearandclothing
• They are alsouse tomake casingofmany electricalappliancessuchas fans,
televisionas they does not allowelectricitytopassthrough, sowe won’tget
electricshock fromtouchingthem

28. Examples
Polythene Polyvinyl chloride(PVC) Polystyrene
• Grocery bags
• Clingfilm for
food wrap
• Pails
• Milk bottles
• Cups
• Water pipes
• Raincoats
• Insulationmaterials for
electrical wires
• Floor coverings
• Sofa upholstery (stuffing
to add padding to
furniture)
• Packingmaterials
• Food containers
• Disposables
utensils
• Boxes to keep
thingscold
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Bakelite
• Plugcovers
• Bottlecaps
• Handles of
cookware and
electrical
appliances
• Cameras
Plastic foam (Styrofoam is type
of polystyrene)
Nylon
• Mattresses
• Cushions
• Paddings
• Artificialsponges
• Clothes(nylon)
• Socks and
stockings
• Strings
• Ropes
Examples

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Properties ofMaterials
• Apropertyofa materialis adescriptionof thecharacteristics
whichithas.Theyareadjectiveswhichtellusaboutthe
material.
• Materialshavedifferent propertiesand characteristics
dependingonwhattheyareusedfor.
• Somematerialsarehard,others aresoft.Somearestrong,
othersareweak.
• Knowingthephysicalpropertiesofamaterialisvery
importantinhelpinguschoosetherightmaterialtomakean
object

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List of properties of materials
1. Waterproof
2. Transparency
3. Flexibility
4. Strength
5. Ability to float or sink (buoyancy)
6. Thermal conductivity
7. Electricalconductivity

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1. Waterproof
• Materialsare classifiedbasedonweather they are waterproofor absorbent
• A waterproofmaterialdoes notabsorbwater atall (alsoknownas water-resistant)
• An absorbentmaterialabsorbsandtakes upwater
• Examplesofwaterproofmaterialsare plastic,glass,metal, ceramics
• Examplesofabsorbentmaterialsare fabricssuchascottonandwoolas wellas
wood
• Waterproofmaterialsare usedwhenever water needs to be kept inor out
• Raincoatsandtents are made ofwaterproofmaterialstokeep rainout
• Boatsneed to be completelywatertighttokeep water out
• Aquariumsare made of waterproofmaterialsto keep water in
• Cardboardandpaper are absorbentbut canbe made waterproofby rubbingwax
over itor sprayinga clear spraysuchas acrylicsprayontoit

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2. Transparency
• Transparency is the ability of the material to allow how much light to
pass through it
• Materials are classified basedon their degree oftransparency to light:
• Transparent: Allows all/most light to pass through
• E.gGlass usein car windscreenand plastic inspectacle lens
• Translucent: Allows some light to pass through
• E.gFrosted glass use inbathroom window,fabrics useinlampshade, plastic in
plastic bag, tracing paper
• Opaque: Allows no light to pass through
• E.gMetal andceramicuse incooking pots, wood useinfurniture,
rubber use intyre andleather use inhandbag

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3. Flexibility
• Flexibility isthe abilityof a material to bend without
breaking
• Materials canbe classifiedinto flexible or rigid(stiff)
• Flexible materials are easy tobend
• Rigid materials are difficult tobend
• Examples of flexible materials are rubber, fabrics, some
plastics,paper
• Examples of rigidmaterials are wood, ceramics,glassand
metal

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4.Strength
• Strength is the ability of material to withstand heavy loads without breaking
• Materials can be classified into strong or weak
• Materials that are strong are difficult to break
• Materials that are weak are easy to break
• Examples of strong materials are metal, wood, plastics, leather
• Examples of weak materials are glass, ceramics
• The strength of materials is relative. For example a metal spoon is stronger
than plastic spoon while a plastic bag is stronger than paper bag
• Most pure metal are weak. However, they can be make stronger combining
with other metals or non-metals. For example, steelis made from iron and
carbon and ismuch stronger than pure iron

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5. Ability tosinkor float (buoyancy)
• Buoyancyisthe abilityofthe materialto sinkor floatinwater
• Materialsthatsinkgo downtothe bottom ofwater
• Materialsthatfloatstay on the surfaceof the water
• Examplesof materialsthatsink aremetals,ceramics,glass,leather
• Examplesof materialsthatfloatarewoodandplastics
• Weatheramaterialsinksorfloatsin waterdependson its density
• For example,apebbleandametalballsinkin waterbecausethey
havehigherdensitythan water.On the otherhand,acorkfloats
on waterbecauseitislessdensethan water

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Sink Float
Materials that go down to the bottom of water Materials that stay on the surface of water
piggy bank marble glass cup
metal spoon leather purse
cork tree branches Ping Pong
ball
plastic spoon rubber duck
paper clip pencil

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6. Thermal conductivity
• Thermalconductivity is thematerialability toallow heattoflowthroughit easily
• Materials are classified as good conductors of heator insulatorof heat
• Good conductors of heatare materialsthatconduct heatvery quickly, allow heattopass
througheasily
• Insulators of heatare materials conduct heatpoorly, do not allow heattopass through
easily (also knownas poor conductor of heat)
• Examples of good conductors of heatare metals usein cookingappliances/utensilsand
electric iron
• Examples of insulatorof heatare wood andplastics usein handleof cooking utensilsand
cooler box

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7. Electrical conductivity
• Electrical conductivity refers to thematerialabilityto allowelectricity topass through
• Materials can beclassified as good conductors or insulatorof electricity
• Good conductor of electricity conducts electricity which is allow electricity topass through
• Insulatorof electricity does notconducts electricity which is does notallow electricity to
pass through
• Examples of good conductor of electricity are metals usein electricalwires andfilamentin
lightbulb
• Examples of insulatorof electricity are ceramic, glass, wood, rubber andplasticusein
casingof plug,wires andswitch

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Electricalconductivity

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When choosing a materialto make an object, the properties of materialmust match the uses andfunctions
of the objects
Choosingthe Right Materials forObjects
No. Material Uses Functions Reasonsfor choosingmaterial
1. Metal Electrical wires Conduct electricity Good conductor of electricity, strong, ductile
2. Plastic Raincoats Keeprain out Waterproof, light, strong, durable
3. Glass Laboratory
apparatus
To dochemical
experiments
Transparent, light, conducts heat to a certain extent
4. Leather Jackets Keepwarm Durable, strong, light, poor conductor of heat
5. Rubber Car tyres To support and
direct vehicle
Hard, strong, flexible, waterproof, durable
6. Ceramics Mugs and cups To contain water Strong, hard,poor conductors of heat
7. Wood Furnitures To hold objects Strong, durable, easily madeinto different shapes
8. Fabrics Clothes To beworn Light, canbedyed, smooth, soft

47. THE END
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