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Name: Class: Date:
Herearetwohypothesesabouthowweseethisbook:
• Lightmusttraveltooureyesfirstandthentothebook.
• Lightmusttraveltothebookfirstandthenisreflectedintooureyes.
Whichhypothesisdoyouthinkiscorrect?
Activity 9.2 How Do We See this Book?
Aims• Totesttwohypothesesabouthowwe
seethings
Apparatus and materials• Torchorlamp,cardboardtubeorlargeboard
Key skills and competencies• Skills:using apparatus and equipment,
observing
• CIT:creativity (planning an investigation),
sound reasoning
Link i t
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Plananexperimentthatwilldeterminewhichofthetwohypothesesiscorrect.You
maywishtouseatorchandacardboardpapertubeorlargeboard(toblockoutlight).
1. Method
Describeyourmethodinthespacebelow.Besuretoexplainhowtocarryoutafair
test.Usediagramstohelpyou.
Checkyourmethodwithyourteacher.Next,carryoutyourexperiment.
2. Observations
3. Conclusion
Whichhypothesisdotheresultssupport?
E.g.
To test hypothesis A, use a cardboard tube or a board to block out light and make the light travel asshown. Observe if the book can be seen clearly.
To test hypothesis B, set up the cardboard tube or board as shown. Again, observe if the book can beseen clearly.
The book can be seen clearly when light from the torch is shone directly at it but not seen clearly when
shone directly into the viewer’s eyes.
Hypothesis B
tube
board
or
tube
board
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Name: Class: Date: Activity 9.3 Investigating Reection in a Plane Mirror
Aims• Toinvestigatethereectionoflightina
planemirror
Apparatus and materials• Rayboxwithslitandpowersupply,paper
sheetwitha180°protractordrawnonit
Forthisexperiment,youwillbegivenasheetofpaperwitha180°protractordrawnonit.
1. Placethebackofaplanemirroronthepaperasshown.
Thelineatrightanglestothemirroriscalledthenormalline.
Key skills• Skills:using apparatus and equipment,
measuring
Link i t
2. Usearayboxtoshinearayoflightontothemirrorat20°fromthenormallineas
showninthediagram.
Thisrayiscalledtheincident ray.
Theangleof20°iscalledtheangle of incidence(i ).
3. Canyouseeareflectedrayoflight?
Measuretheanglebetweenthenormallineandthereflectedray.
Thisiscalledtheangle of reflection(r ).Recordthevalueofr inthetableonthe
nextpage.
normal line
ray box
0
0 1 8 0
9 0
1 8 0
Yes
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4. Repeatusingotheranglesofincidence.Recordyourresultsinthetable.
5. Prediction Iftheangleofincidenceis35°,whatwilltheangleofreflectionbe?
Testyourpredictionbydoinganexperiment.
Whatwastheresultfortheangleofreflection?
6. Conclusion
Completethefollowingsentence:
Theangleofincidenceis (equalto/largerthan/smallerthan)theangleofreflection.
Angle of incidence (i ) Angle of reection (r )
35˚
35˚
20˚ 20˚
equal to
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Name: Class: Date: Activity 9.4 Investigating Phases of the Moon
Aims• Tobuildamodeltoinvestigatethe
appearanceoftheMoonatdifferenttimes
ofthemonth
Apparatus and materials
• Tennisball,torchorlamp
Key skills and competencies• Skills:using apparatus and equipment
observing
• CIT:creativity (designing a model)
Link i t
(A) Observing the Moon
1. LookattheMooneachnightatabout9.00pm.
2. Inthetablebelow,drawhowthephasesoftheMoonchangeover30days.Write
inthedateasshownintheexample.
Day 1 3 52 4 6
Phase
Date
Day 7 9 118 10 12
Phase
Date
Day 13 15 1714 16 18
Phase
Date
Phase
2 May Date
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(B) Modelling the phases of the Moon
Method
Questions
1. HowareweabletoseetheMoon?
2. ExplainhowweareabletoseethedifferentphasesoftheMoon.
Day 25 27 2926 28 30
Phase
Date
You are given a tennis ball and a lamp or torch. In groups, discuss how you would be able
to demonstrate the phases of the Moon as seen on Earth. Describe your method below or
draw a diagram to show your set-up.
Day 19 21 2320 22 24
Phase
Date
1. One student should hold the torch (represents the sun). Another student should hold the tennis ball
(represents the Moon). Another student can represent the Earth.
2. The students representing the Sun and the Earth should face each other. The student with the ballshould stand in between them.
3. The student representing the Earth should rotate on the spot. As he or she does this, the student withthe ball should revolved around the student representing Earth.
We are able to see the Moon because it reects light from the Sun.
We see different phases of the Moon because as the Moon orbits the Earth, different parts of it reect light
from the Sun.
8/3/2019 PWB Chapter 9
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Name: Class: Date: Activity 9.5 Investigating Images in Plane Mirrors
Aims• Toinferthecharacteristicsofimagesformed
inplanemirrors
Apparatus and materials• Sheetofglass,mirrorholder,whitescreen
(orsheetofpaper),twoBunsenburners,smallplanemirror,plasticsheet
Inthisexperiment,asheetofglassisused.Theglassactspartlyasaplanemirroralthoughit
istransparent.
1. Placeasheetofglassuprightonthetable.
PlaceaBunsenburnerinfrontofit.
2. Lookintothe‘mirror’toseetheimageofthe
Bunsenburner.
(a) Istheimageuprightorinverted?
(b) Istheimagebigger,smallerorthesamesize
astheobject?
3. Placeawhitescreenorsheetofwhitepaperbehindtheglass.Moveitbackwardsand
forwardstotrytogettheimageonthescreen.
Key skills and competencies• Skills:using apparatus and equipment,
observing
• CIT:sound reasoning
Link i t
sheet of glass
white screen
Canyougetanimageonthescreen?
The image is upright.
The image is the same size as the object.
No
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Istheimageinthemirrorturnedsideways?
Whatisthiscalled?
6. Conclusion
Fromyourobservations,statefivecharacteristicsoftheimageformedbyaplane
mirror.
4. (a) MoveanotherBunsenburnerbehindtheglassuntilitisexactlyalignedtotheimage
ofthefirstBunsenburner.MeasurethedistancesofthetwoBunsenburnersfrom
theglassmirror.
Whatdoyounoticeaboutthedistancesoftheobject(thefirstBunsenburner)and
theimage(thesecondBunsenburner)fromtheglass?
(b) RepeatwiththeBunsenburnerplacedatdifferentdistancesfromtheglassmirror.
Istheresultthesame?
5. (a) Writeawordonaclearplasticsheet.
(b) Holdthesheetinfrontofaplanemirror.
Canyoureadtheword?
Onthediagram,drawwhatyouseeontheplasticsheetandinthemirror.
plastic sheet plane mirror
1. The image is upright.
2. The image is the same size as the object.
3. The image cannot be formed on a screen that is behind the mirror.
4. The distances of the image and the object from the mirror are equal.
5. The image is laterally inverted.
Yes
Lateral inversion
The two distances are the same.
Yes
Yes
8/3/2019 PWB Chapter 9
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Name: Class: Date:
narrow beam
of light
Activity 9.6 Investigating Refraction
Aims• Toobservewhathappenswhenlightpasses
throughablockofglass
Apparatus and materials• PartA: Round-bottomedask,highintensity
torchorlaserlight,uorescein(orcoffee-mate)solution,sourceof
smoke(e.g.stickofincense)
(A) [DEMO] Bending light
1. Setuptheapparatusshowninthediagram.
Tomakelightvisible,addfluorescein(orcoffee-mate)tothewaterandintroducesomesmoketotheairabovethewater.
2. Allowanarrowbeamoflighttopassfromairtowater.
Thebeamoflight
(bends/doesnotbend).
• PartB: Rectangularglassblock,raybox,
sheetofwhitepaper(A4),pencil
Key skills and competencies• Skills:using apparatus and equipment,
observing
• CIT:sound reasoning
Link i t
(B) How does light move through glass? o p t i o n al f o
r
N ( A )
1. Placeaglassblockonasheetofwhitepaper.Useapenciltodrawtheoutlineofthe
block.
2. Usearayboxtoshineanarrowbeamoflightintotheglassblockasshownbelow.
sheet of white paper
sheet of white paper
ray boxglass block
bends
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Canyouseetherayinsidetheglassblock?
Doesthelightbendwhenitenterstheglassblock?
Lookfortheraycomingoutoftheglassblock.
Doesthelightbendagainwhenitcomesoutoftheglassblock?
3. Lookthebeamsoflightonthepaper.Onthepaper,drawtwocrossestoshowthe
pathoflightgoingintotheblockandtwomorecrossestoshowthepathoflight
comingout.
4. Removealltheapparatus.Usearulertojointhecrossestoshowthemovementof
thelight.Also,drawthetwonormalsatrightanglestotheglassblock.
5. Conclusion
Completethefollowingsentences.
(a) Lightmovingfromtheairintotheglassisbent(orrefracted)
(towards/awayfrom)thenormal.
(b) Lightmovingfromtheglasstotheairisrefracted
(towards/awayfrom)thenormal.
away from
towards
Yes
Yes
Yes
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Name: Class: Date: Activity 9.7 How Are the Colours in a Rainbow Formed?
Aims• Toobserveaspectrumofwhitelight
Apparatus and materials• Raybox,twoglassprisms,whitescreen
1. Setuparayboxandaprismasshowninthediagram.
2. Shineabeamoflightthroughtheprismandontothescreen.
Youshouldseesomecoloursonthescreen.(Youmayhavetoturntheprismtoseethe
coloursclearly.)
Listthecoloursyouseeonthescreen,startingfromthecolournearestpointX.
3. Placeasecondprismasshowninthediagrambelow.
Key skills• Skills:using apparatus and equipment,
observing, inferring
Link i t
X
ray box
prismscreen
(a) Whatcolourisformedonthescreennow?
White
Red, Orange, Yellow, Green, Blue, Indigo, Violet
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(b) Whathasthesecondprismdone?
Questions
1. Whatismeantby‘whitelight’?
2. Whatwordisusedtodescribethesplittingofwhitelightintoseparatecolours?
3. (a) Whichcolourisbentthemostbytheglassprism?
(b) Whichcolourisbenttheleastbytheglassprism?
4. Nameoneeverydayphenomenonthatinvolvesthesplittingofwhitelightintocolours.
Light that is a mixture of all the colours of the spectrum (and which we see as colourless)
Dispersion
Violet light
A rainbow/Colours on (soap) bubbles
The second prism has recombined the colours of the spectrum.
Red light
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Activity 9.8 How Do Objects Appear in Light of Different Colours?
Aims• Toobservehowobjectsappearinlightof
differentcolours
Apparatus and materials• Rayboxortorch;red,greenandbluelters
tottherayboxortorch;white,red,greenandblueobjects
1. Shinewhitelightfromarayboxortorchontowhite,redandgreenobjects(ina
darkenedroom).Notethecolourstheobjectsappearin.Recordyourresultsinthetable
givenbelow.
Key skills and competencies• Skills:using apparatus and equipment,
observing, predicting
• CIT:creativity (testing predictions)
Link i t
Colour of light shining on the object
White Red Green Blue
White White
Red
Green
Colour of object
in daylight
o p t i o n al f o
r
N ( A )
Name: Class: Date:
2. Placearedfilterinfrontoftherayboxoroverthetorch.Shinetheredlightontoeach
objectandagain,notethecolourtheobjectsappeartobe.
3. Repeatusinggreenfilters.
4. Results
Completethetablewithyourobservations.
ray box
object
Red
Red
Black
Green
Black
Green
Blue
Black
Black
Red
Green
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5. Making and testing predictions
Youwillnowuseyourunderstandingofcolouredlighttomakepredictions.Youwillthen
doanexperimenttotestthepredictions.
(a) Whatcolourwillablueobjectappeartobeinlightofthefollowingcolours:white,
red,greenandblue?Recordyourpredictionsinthetablebelow.
(b) Testyourpredictionsbydoinganexperiment.Recordyourobservationsinthetable.
(c) Wereyourpredictionscorrect?
Questions
1. Inwhatcolouroflightisanobjectthesamecolourasitisindaylight?
2. Underwhatconditionsdoesacolouredobjectappearblack?
3. Whatdoscientistsdoifexperimentsshowthattheirpredictionsarewrong?
Colour of light shining on a blue object
White Red Green Blue
Predicted results
Experimental results
(Blue)
Blue
(Black)
Black
(Black)
Black
(Blue)
Blue
Yes/No
In white light and in light of the same colour as that of the object
An object appears black when the light shone on it is absorbed and not reected at all.
E.g. Scientists can conduct more experiments, modify their models/ideas or rene their predictions.