Photosynthesis produces glucose and polysaccharides such as starch.

A. Need lights for plants - skip if off-campus.

B. Carbon dioxide absorption.

• Carbon dioxide forms carbonic acid in water: CO₂ + H₂O -> H₂CO₃
• Use Phenol Red as a pH indicator: red in basic and neutral solutions, turning yellow in acid. Dilute by adding 10 ml Phenol Red to 90 ml of aged tap water or distilled water.
• Make the solution acidic (yellow) by blowing CO₂ into the solution.
• Elodea in screw-top test tubes: different sizes and different light treatments.

C. Oxygen generation demonstration - skip if off-campus.

D. Pigment extraction: chlorophylls, carotenoids and xanthophylls (a polar carotenoid).

• Grind spinach in acetone.
• Filter the solution. NOTE: do not over-rinse; you only need a tiny, concentrated sample for the chromatography.
• Separate by chromatography paper; the solution, with the suspended pigments, should move up by capillary action.

E. Absorption spectrum: need Spectronic 20D - skip if off-campus.