Prelab Exercise
- Fill the Color field in the table below
- Use plot.ly to create a line graph with the 3 samples below (A, B, C)
- plot % Reflectance on the Y-axis and Wavelength (nm) on the X-axis
-
% Reflectance
Color
nm
A
B
C
400
68
92
78
425
40
71
77
450
90
38
51
475
97
49
57
500
100
92
45
525
100
100
66
550
96
97
100
575
98
96
100
600
96
98
100
625
97
80
100
650
79
71
100
675
56
96
100
700
88
100
100
Stop and Think: Reflectance
A sign of plant health is viewed through the near infra-red. While we cannot see this spectrum of light with our eyes, we can use other sensors to detect this light. Compare the images of the Black & White with the Infra-red image. What differences can you see in the 2 images that will help you understand how this is a useful measure of plant health? How do you think this is corresponds to the table above?
Measuring Absorbance
- Turn on the SpectroVis units and let the Labquest continue to calibrate and warm-up
- Prepare a blank colorimetry tube by adding acetone.
- Place some of the spinach extract in a cuvette and obtain the continuous absorbance spectrum.
- the extract may be too concentrated, and you may have to dilute the amount to obtain a reading
- Press on the File Cabinet icon to save the readings
- Place some of the Spirulina extract in a cuvette and obtain the continuous absorbance spectrum.
- Press on the File Cabinet icon to save the readings
- Plot OD against wavelength and observe the absorption spectrum of the extract.
