Task C
1. Measurement of the wavelength of a laser
1. 1. Calculate the angie a between the 0th and 1st order maximum.
(3 Marks)
You need to know the distance from grid to floor L and between the two marks on the black paper X
(Fig. 1.2).
L= 1.00 m, X=0.16m
Formula for a: a = arctan (X/L) = tan-1 (X/L)
Angle a= 9. 12 degree
Correctformula: 2 marks
Correctvalue: 1 mark (± 1 degree)
.
2. Determine the grating constant d, i.e. the distance between two lines on the grid. Give
the answer in the unit of metre.
(3Marks)
d = I/ 300000m = 3.33 10-6m = 0.00000333 m
Gratingconstantri= 0.00000333m -= 3?/5^ '/0 '<?yl
Correct formula: 2 marks
Correct value: 1 mark
1.3. Waveiength of the laser
(6 Marks}
Writethe transposed formula used for wavelength determination. Calculatethe
wavelength of the Sightfor the 1st maximum (n = 1) using your measured values.
?i=d*sina
\ = 3. 33 10-6* sin (9. 12°) = 0. 000000567 m = 527 nm = 527. 10-9 m
\ =527 109m
Correct formula: 3 marks
Correctvalue: 2 marks (527±50nm)
Correct units: 1 mark
^=527nm
2. Investigation of textures
(10 Marks)
2. 1. Determination of the diffraction angle of textures A - E
Table 2. 1a
distance L
texture
distance X
anglea
(degree)
733
732
731
725
725
725
726
725
0, 63
0, 67
0, 63
0, 55
8,5
0, 55
7,5
0, 59
0, 39
0,40
0,40
724
723
723
724
0,32
722
0,32
0, 32
0,20
2,5
723
722
0, 16
0,16
Table 2. 1b
textures
mean value of the
standard deviation
angle (degree)
(degree)
0,64
0,018
0,57
0,019
0,40
0,000
0,32
0, 17
0,000
B
c
0,019
Values are only an example
Mean value: Accepted ranges A to E:0. 65, 0. 55, 0. 40, 0. 30, 0. 20± 0. 03 degree
Valuewithinthe range 1 mark, valueoutsidethe rangeYzmark.
Standard deviation: Eachcorrect value 1 mark
2. 2. Diagram: texture A - E - diffraction angle
Paste your diagram!
0, 700
0,600
0,500
g 0,40)
BO
0, 300
0, 20)
0, 100
0, 000
c
texture
Formal (3 marks):
Correctsize (3/4 of page): 1 mark
Labels and units on the axes: 1Amark each axis
Results and error bars with meaningful symbols: 1 mark
Correctness (7 marks):
Correcttransfer ofthe values of Table 2. 1b into the graph: 3 marks
Correctplot of the upper part of the error bars: 2 marks
Correct plot ofthe lower part ofthe error bars: 2 marks
(10 Marks)
2. 3. Possibie forger studios
Insert the diffraction angie
3 Marks)
Table 2.3
sample
distance L
distance)(
(degree)
0,39
0,40
0,40
726
725
724
p
angle a
Diffractionangle of sample?:a = 0,40 ±0,03 degree(mean value and standard
deviation)
Possible studios of the forgery: sea
Correct values in table 2. 3: 1 mark
Correctvalue of diffraction angle (0, 40 ± 0, 03): 1 mark, withoutstandard deviation:Yi mark
Correct answer for studios: 1 mark
3. IdentifkatioFi ©fa fluid
3. 1. Adjustment of the experiment
Write down the value of the zero reference mark!
(1 SViark)
A value is given: 1 mark
3.2. Whichfluid showsopticaEactivity?
insert your result in She table 3. 21
{3 Marks)
Table 3.2
fluid sample
yes
no
A
B
Correct identificationof all liquids including confirmation ofthe lab assistant: 3 marks
Correct identificationof 2 liquids including confirmation of the lab assistant: 2 marks
Correct identificationof 1 liquid including confirmation ofthe lab assistant: 1 marks
3. 3. Measurement of the optical activity at different concentrations
(8 Marks)
Table 3. 3a
dilution
concentration
rotation anglea
[g/lOOml]
[degree]
original
50
115
original
50
120
originai
50
120
25
50
25
48
25
51
12, 50
25
12,50
25
12, 50
23
6, 25
15
6, 25
15
6, 25
12
CakuSatethe mean value and the standard deviation.
Table 3. 3b
diiution
concentration
mean value of the
standarddeviation
tg/lOOmi]
rotation angle
[degree]
a [degree]
original
50
2.4
118.3
25
1.2
49.7
12, 50
0.9
24.3
6, 25
1.4
14.0
Correctvaluesofthe rotationangle(meanvalue:110± 20, 50±20,30±20, 15± 10degree):4 marks(1for
each dilution)
Values outside range: Yi mark
Standard deviation: Eachcorrect value 1 mark
3.4. Set up of a calibrationgraphfor the opticai rotation
; 10 Marks)
Drawa diagram on a miilimeter paper, in whichthe rotation anglesa are pSotted in relation to the
concentration. Insert this diagram here! Be sure to include mean values, error bars and a line of best
fit!
140,3
1?0,0
:GO,0
VJ.O
®
r;' 0
0
;pncentrotk~l:n/n/l00rr;;
Formal (3 marks):
Correctsize(3/4 of page): 1 mark
Labels and units on the axes: Yi mark each axis
Results anderror barswith meaningfulsymbols: 1 mark
Correctness (7 marks):
Correct transfer of the values of Table 3. 3b into the graph: 3 marks
Correct plot of the upper part of the error bars: 2 marks
Correct plot ofthe lowerpart ofthe error bars: 2 marks
3.5 Determination of the specificrotation angles
(8 Marks)
Tabie3.5
dilution
concentratson
[g/100ml]
original
mean value specific
rotation angle
standarddevEatio
[a] [degree.mi/dm.g]
g]
50
n[degree.ml/dm.
2,4
118,3
25
2,5
99,3
12, 50
3,8
97,3
6, 25
11,3
112,0
One markfor each correct value
(10 Marks)
3. 6 Diagram: Specific rotation angle in relation to the concentration
130
120
0
110
8 loo
^s
E
s
0
90
80
w
-i 7Q
^
rs
c:
0
60
50
-5 40
u
.
£ 30
&
" 20
1C
0
5
10
15
20
25
30
35
40
AS
50
concentr. stion / g/lOOni)
Formal (3 marks):
Correct size (3/4 of page): 1 mark
Labels and units on the axes: Yi mark each axis
Results and error barswith meaningfulsymbols: 1 mark
Correctness (7 marks):
Correct transfer of the values of Table 3. 5 into the graph: 3 marks
Correct plot of the upper part of the error bars: 2 marks
Correct plot ofthe lowerpart ofthe error bars: 2 marks
(9 Marks)
3. 7 interpretation of the results
Tick the appropriate answers'
Table 3.7
The constant function is based on the fact that the specific rotation
angle of a substance is independent of the concentration.
The increase of the concentration leads to smaller values of the specific
rotation angle.
The uncertainties of the measured values arise from inaccurate
measurements of the angle.
The uncertainties of the measured values arise from inaccurate
dilutions.
Correct
Wrong
5&
The uncertainties of the measured values arise from varying intensities
of the laser.
The uncertainties of the measured values arise from the wave length of
the laser.
The uncertainties of the measured values arise from the measuring
process.
The uncertainties of the measured values can be reduced in calculating
a line of best fit.
The uncertainties of the measured values can be reduced by additional
measurements.
Correct answers: 1 mark per line
3.8 Determination of the substance
3.8. 1 The specific rotation angle [a] =^07 degree
4
Correct value within 1^± 10 degree: 3 Yi marks
Value outside range? 2 marks
3.8.2 SeEectthe substance which has a rotation angie closest to your result! Tick the
appropriate answers!
Table 3.8
material
yes
fructose
glucose
saccharose
tartaricacid
ascorbicacid
Correct answer: 2 Yi marks (Yi mark each line)
Possible studios of the forgery
identification of the studio
Possible studio of the forgery: sea, forest
Correct answer: 2 marks
Only one correct studio: 1 mark
no
CHALLENGE 2
Marking scheme D E
TASK D
The science team's conclusions: Whichare possible places of origin ofthe counterfeit
painting?
1. Summarizeyour results asa team inthetable "Scienceteam's summary"to helpyoucome
to a common statement in table "Conclusion".
1. 1. Fill in "Y" (appropriate statement) or "N" (not applkable/wrong) in the table.
(0 Marks)
Table "Science team's summary"
Methods of investigations
Studio in
Studio at the
Studio at the
the forest
sea
lake
Chemical analysis of the art studios' samples
N
Optical activity investigation of the liquid of
Mesembryanthemum crystallinum bladder
N
N
cells
Visual investigation of the canvas sample
N
Investigation of Mesembryanthemum
crystallinum
Investigation of the pieces of evidence from
the car trunk
N
N
N
N
1. 2. Indicate your common statement in the table "Science team's conclusion" with an "X" in
the relevant field.
(6 Marks)
Table: "Scienceteam's conclusion"
Indicate your conclusion in the following table with an "X" in the
relevant field. According to the scientific findings, the science team
believes that the art forgery hasbeen committed in the following
studio:
Art studio in the forest
Art studio at the lake
Art studio at the sea
1
Version =11. 04. 2015
CHALLENGE 2
Marking scheme A D E
TASK E
1. Facts about....
Evaluate the statements in the table "Facts about.... "!
(24 Marks)
Correct
Jeans have originally been dyed with plant dye
Facts about
colours
Color of materials depends partly on the
spectra! composition ofthe incoming light.
Artifical blood is a chemical compound that
contains chromium.
Kidney stones can partly be composed of
Facts about
crystal
calcium oxalate.
Diffractionof X-rays is used to determine the
structure of crystals.
Rock crystal is pure Si(IV)oxide and therefore
not classified as a crystal.
Compared to blood plasm, the isotonic sodium
chloride solution is an isoosmotic solution.
Facts about blood
Blood pressure of 114 mm Hg corresponds to a
pressure of a 1. 5 m high in a water column.
The chromium concentration in human whole
blood is ~100 [ig/\.
The following molecules serve as
photoreceptors: Chlorophyll in photosynthesis,
phytochrome in growth regulation, rhodopsin
Facts about light
in the vision process,.
Molecules with high symmetry show optical
activity.
Lambert-Beer's law is valid only for red
solutions.
11
Version =11. 04. 2015
Incorrect