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How to get 6 in DCP
Mr.T’s powerpoint for cheaters in chemistry
DCP1 presenting data
             Trial                Diameter of circle (cm)
               1                           17.10
               2                           23.60
               3                           16.20
               4                           21.30

                                           NOT AT ALL
Volume of oil drop = 0.01cm   3




      •What is missing?
      •Are there any mistakes?
      •What mark would this section be awarded?
DCP1 presenting data
         Trial number            Diameter of circle (cm) ±0.05cm
               1                               17.1
               2                               23.6
               3                               16.2
               4                               21.3


109 drops in 1cm3 ± 0.05cm3                  COMPLETE!

Qualitative data:

When the oil drop made contact with the surface of the water it
immediately spread out into a distorted circle. The lycopodium
powder was pushed back by the spreading oil.
Summary
•   Remember units
•   Include uncertainties
•   Include ALL raw data
•   Include qualitative data
DCP2 processing data
Trial 1 diameter = 17.1
Area = 918
Diameter = V/A = 918 / 0.00917 = 0.0000404cm



         •What is missing?
         •Are there any mistakes?
         •What mark would this section be awarded?



                            Not at all
DCP2 processing data
   Diameter of circle (cm) ±0.1cm     Radius of circle (cm) ±0.05cm
                 17.1                                8.55
                 23.6                                11.53
                 16.2                                8.10
                 21.3                                10.65

Average radius
(8.55 + 11.53 + 8.1 + 10.65) / 4 = 9.71cm ± 0.05cm

109 drops in 1cm3 ± 0.05cm3
Therefore average volume of 1 drop = 1/109 = 0.00917cm 3

% uncertainty volume = (absolute uncertainty / volume measured) x 100
= (+/-0.05cm3 / 1cm3) x 100 = 5%
DCP2 Processing data
Average radius = 9.71cm
Average volume of 1 drop = 1/109 = 0.00917cm3

Area of oil layer = πr2 = π x 9.712 = 264.17cm2
Height of cylinder = Volume of cylinder / Area
Volume of oil layer = volume of oil drop

Height of oil layer = 0.00917cm3 / 264.17cm2 = 3.47 x 10-5 cm
Assuming the oil layer is 1 molecule in height, and each molecule contains 12 carbon
Atoms, diameter of a carbon atom = 3.47 x 10-5 cm / 12 = 2.89 x 10-6 cm


                                      COMPLETE!
Summary
•   Show all steps in calculations
•   Convert units where necessary
•   Show units throughout
•   State equations and define terms
•   Explain assumptions
DCP3 Presenting data
Average radius = 9.71cm ± 0.05cm
%uncertainty = (0.05cm/9.17cm) x 100 = 0.55%
Average volume of 1 drop = 1/109 = 0.00917cm3 ± 4.59 x 10-4cm3
%uncertainty = 5%

Area of oil layer = πr2 = π x 9.712 = 264.17cm2 0.55% + 0.55% = 1.10%
Height of cylinder = Volume of cylinder / Area
Volume of oil layer = volume of oil drop

Height of oil layer = 0.00917cm3 / 264.17cm2 = 3.47 x 10-5 cm 1.10% + 5.00% = 6.10%
Assuming the oil layer is 1 molecule in height, and each molecule contains 12 carbon
Atoms, diameter of a carbon atom = 3.47 x 10-5 cm / 12 = 2.89 x 10-6cm ± 6.10%



                                       COMPLETE!
Summary
    EVERYONE misses uncertainties for a COMPLETE

•   Absolute uncertainties do not change in the average
•   Convert to % uncertainty after calculating average
•   If data is multiplied or divided % uncertainties add
•   Quote percentage uncertainty with final answer

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Radius of a carbon atom dcp practice

  • 1. How to get 6 in DCP Mr.T’s powerpoint for cheaters in chemistry
  • 2. DCP1 presenting data Trial Diameter of circle (cm) 1 17.10 2 23.60 3 16.20 4 21.30 NOT AT ALL Volume of oil drop = 0.01cm 3 •What is missing? •Are there any mistakes? •What mark would this section be awarded?
  • 3. DCP1 presenting data Trial number Diameter of circle (cm) ±0.05cm 1 17.1 2 23.6 3 16.2 4 21.3 109 drops in 1cm3 ± 0.05cm3 COMPLETE! Qualitative data: When the oil drop made contact with the surface of the water it immediately spread out into a distorted circle. The lycopodium powder was pushed back by the spreading oil.
  • 4. Summary • Remember units • Include uncertainties • Include ALL raw data • Include qualitative data
  • 5. DCP2 processing data Trial 1 diameter = 17.1 Area = 918 Diameter = V/A = 918 / 0.00917 = 0.0000404cm •What is missing? •Are there any mistakes? •What mark would this section be awarded? Not at all
  • 6. DCP2 processing data Diameter of circle (cm) ±0.1cm Radius of circle (cm) ±0.05cm 17.1 8.55 23.6 11.53 16.2 8.10 21.3 10.65 Average radius (8.55 + 11.53 + 8.1 + 10.65) / 4 = 9.71cm ± 0.05cm 109 drops in 1cm3 ± 0.05cm3 Therefore average volume of 1 drop = 1/109 = 0.00917cm 3 % uncertainty volume = (absolute uncertainty / volume measured) x 100 = (+/-0.05cm3 / 1cm3) x 100 = 5%
  • 7. DCP2 Processing data Average radius = 9.71cm Average volume of 1 drop = 1/109 = 0.00917cm3 Area of oil layer = πr2 = π x 9.712 = 264.17cm2 Height of cylinder = Volume of cylinder / Area Volume of oil layer = volume of oil drop Height of oil layer = 0.00917cm3 / 264.17cm2 = 3.47 x 10-5 cm Assuming the oil layer is 1 molecule in height, and each molecule contains 12 carbon Atoms, diameter of a carbon atom = 3.47 x 10-5 cm / 12 = 2.89 x 10-6 cm COMPLETE!
  • 8. Summary • Show all steps in calculations • Convert units where necessary • Show units throughout • State equations and define terms • Explain assumptions
  • 9. DCP3 Presenting data Average radius = 9.71cm ± 0.05cm %uncertainty = (0.05cm/9.17cm) x 100 = 0.55% Average volume of 1 drop = 1/109 = 0.00917cm3 ± 4.59 x 10-4cm3 %uncertainty = 5% Area of oil layer = πr2 = π x 9.712 = 264.17cm2 0.55% + 0.55% = 1.10% Height of cylinder = Volume of cylinder / Area Volume of oil layer = volume of oil drop Height of oil layer = 0.00917cm3 / 264.17cm2 = 3.47 x 10-5 cm 1.10% + 5.00% = 6.10% Assuming the oil layer is 1 molecule in height, and each molecule contains 12 carbon Atoms, diameter of a carbon atom = 3.47 x 10-5 cm / 12 = 2.89 x 10-6cm ± 6.10% COMPLETE!
  • 10. Summary EVERYONE misses uncertainties for a COMPLETE • Absolute uncertainties do not change in the average • Convert to % uncertainty after calculating average • If data is multiplied or divided % uncertainties add • Quote percentage uncertainty with final answer