National Centre for Biotechnology Education and Science and Plants for Schools www.ncbe.reading.ac.uk Investigating Photosynthesis Copyright © Dean Madden,

pH 7.6pH 7.8pH 8.0pH 8.2pH 8.4pH 8.6pH 8.8pH 9.0pH 9.2 0.04% carbon dioxide in the atmosphere Increasing concentration of carbon dioxide in the indicator Decreasing concentration of carbon dioxide in the indicator

Comparison of sample tube with standards