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RESULTS
Absorbance
(or optical density) is the ratio between the light intensity which strikes the
culture (Io) and the intensity transmitted to the culture (I). This
value is derived from log (Io/I). When the cellular concentration
increases, the culture would become more turbid, meaning that less light would
pass through the liquid a more of it would be absorbed.
Absorbance
doesn't have any units because it’s the ratio of the amount of light that
passes through a solution compared to the amount of light that is passed into
it.
We
measured the absorbance of the cultures at a 600nm wavelength because it is a standardized
measurement to verify absorbance in solutions.
1) Culture #1: 30mL of water
Solution
|
Bacteria culture
|
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,01849
|
593,92
|
0,01840
|
596,88
|
0,01860
|
599,84
|
0,01840
|
602,8
|
0,01811
|
605,76
|
0,01806
|
608,72
|
0,01746
|
611,68
|
0,01769
|
614,64
|
0,01775
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,93931
|
593,92
|
0,93769
|
596,88
|
0,92714
|
599,84
|
0,92588
|
602,8
|
0,92284
|
605,76
|
0,92763
|
608,72
|
0,92125
|
611,68
|
0,92367
|
614,64
|
0,91083
|
|
Absorbance: 0,92284 – 0,01811 = 0,90473
|
2) Culture #2 (0,0067 g/ml)
Solution
|
Bacteria culture
|
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,00593
|
593,92
|
0,00625
|
596,88
|
0,00512
|
599,84
|
0,00489
|
602,8
|
0,00384
|
605,76
|
0,00255
|
608,72
|
0,00222
|
611,68
|
0,00200
|
614,64
|
0,00327
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,92234
|
593,92
|
0,91922
|
596,88
|
0,91013
|
599,84
|
0,90863
|
602,80
|
0,90400
|
605,76
|
0,91133
|
608,72
|
0,90636
|
611,68
|
0,90692
|
614,64
|
0,89399
|
|
Absorbance: 0,90400-0,00384 =0,90016
|
3) Culture #3 (0,0067)
Solution
|
Bacteria culture
|
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,02991
|
593,92
|
0,02992
|
596,88
|
0,02944
|
599,84
|
0,02905
|
602,8
|
0,02873
|
605,76
|
0,02822
|
608,72
|
0,02720
|
611,68
|
0,02662
|
614,64
|
0,02596
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
1,02914
|
593,92
|
1,02800
|
596,88
|
1,01537
|
599,84
|
1,01366
|
602,8
|
1,00966
|
605,76
|
1,01472
|
608,72
|
1,01065
|
611,68
|
1,00958
|
614,64
|
0,99727
|
|
Absorbance: 1,00966-0,02873 = 0,98093
|
4) Culture #4 (0,0100 g/ml)
Solution
|
Bacteria culture
|
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,01535
|
593,92
|
0,01630
|
596,88
|
0,01590
|
599,84
|
0,01566
|
602,8
|
0,01476
|
605,76
|
0,01356
|
608,72
|
0,01211
|
611,68
|
0,01147
|
614,64
|
0,01231
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
1,01810
|
593,92
|
1,01512
|
596,88
|
1,00610
|
599,84
|
1,00249
|
602,8
|
0,99841
|
605,76
|
1,00689
|
608,72
|
1,00089
|
611,68
|
1,00156
|
614,64
|
0,98540
|
|
Absorbance: 0,99841-0,01476 = 0,98365
|
5) Culture #5 (0,0144 g/ml)
Solution
|
Bacteria culture
|
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,01227
|
593,92
|
0,01213
|
596,88
|
0,01111
|
599,84
|
0,01134
|
602,8
|
0,01020
|
605,76
|
0,00933
|
608,72
|
0,00837
|
611,68
|
0,00787
|
614,64
|
0,00837
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
1,02359
|
593,92
|
1,02241
|
596,88
|
1,01160
|
599,84
|
1,01166
|
602,8
|
1,00764
|
605,76
|
1,01265
|
608,72
|
1,00480
|
611,68
|
1,00746
|
614,64
|
0,99321
|
|
Absorbance: 1,00764-0,01020= 0,99744
|
6) Culture #6 (0,0256 g/ml)
Solution
|
Bacteria culture
|
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
1,12351
|
593,92
|
1,12525
|
596,88
|
1,10956
|
599,84
|
1,10923
|
602,8
|
1,10365
|
605,76
|
1,11113
|
608,72
|
1,10340
|
611,68
|
1,10152
|
614,64
|
1,08512
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,04657
|
593,92
|
0,04672
|
596,88
|
0,04602
|
599,84
|
0,04511
|
602,8
|
0,04345
|
605,76
|
0,04209
|
608,72
|
0,04030
|
611,68
|
0,03910
|
614,64
|
0,03909
|
|
Absorbance: 1,10365-0,04345= 1,06020
|
7) Culture #7 (0,0333g/ml)
Solution
|
Bacteria culture
|
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
0,06241
|
593,92
|
0,06271
|
596,88
|
0,06072
|
599,84
|
0,05984
|
602,8
|
0,05774
|
605,76
|
0,05526
|
608,72
|
0,05325
|
611,68
|
0,05183
|
614,64
|
0,05161
|
|
Wavelength (±0,01nm)
|
Absorbance
|
590,96
|
1,16439
|
593,92
|
1,15925
|
596,88
|
1,14791
|
599,84
|
1,14328
|
602,8
|
1,13782
|
605,76
|
1,14632
|
608,72
|
1,13356
|
611,68
|
1,13724
|
614,64
|
1,11817
|
|
Absorbance: 1,13782-0,05774= 1,08008
|