1. Pigments of Photosynthesis
Ch. 4

2. Florida standard and learning goal
SC.912.L Identify the reactants, product, and basic functions of photosynthesis
Learning Goal: By the end of this lesson, students will be able to describe the process of how pigments allow plants absorb the different wavelengths of visible light

4. Sunlight spectrum

5. Spectrum of light

6. Plant pigment

7. Why are these pigments?

8. Paper Chromatography Experiment

9. Lab safety Care and purposeful movement No horseplay
Be precise and accurate in scientific work
If solvent (alcohol) gets on hands, wipe off with paper towel
Glassware care: never touch broken glass
Work in teams of three

10. Cooperative Learning Groups of 3 students
Materials to gather:
Glass jar
Chromatography paper
Solvent (alcohol)
Ruler
Pencils
Spinach leaf pigment ( one group will use orchid flower pigment )

11. Procedure:
Make a straight line with your ruler 2 cm from bottom of chrom. paper
Add about 1 ½ cm of alcohol to your glass jar
Apply spinach pigment heavily to the line on your chromatography paper
Carefully place paper into jar and into alcohol note: do not let the alcohol level go above pigment
Allow alcohol to draw up through paper and spread out 20min
Work on questions during this time
Once pigment is spread and visible. Mark top of each color and measure in mm for original pigment line. Next measure to sovent line. Record data
Rf = Distance pigment traveled
Distance solvent traveled

13. Data Table A: Distance Alcohol Traveled: ___________ mm Filter Paper
Use colored pencils to draw your observations
Before Paper
Chromatography
After Paper
Distance Alcohol Traveled: ___________ mm

14. Data Table B: Color of Pigment Distance Traveled (mm) Rf value
Chlorophyll a
Chlorophyll b
Carotene
Xanthophyll

15. Analysis Questions: Write the question.
Did the leaf you tested contain different pigments? Refer to your results to support your answer.
Why did the separation of pigments in the spinach extract occur as it did? (i.e. How does paper chromatography work?)
Why are leaves green even though other pigments are present?
Based on what you have learned in this lab, explain why leaves tend to change color in autumn in New England.