2.23: Practical: Investigate Photosynthesis, Showing the Evolution of Oxygen from a Water Plant, the Production of Starch and the Requirements of Light, Carbon Dioxide and Chlorophyll

INVESTIGATING PHOTOSYNTHESIS

Diagram showing Experiment to Investigate the Effect of Light intensity on Photosynthesis in Pond Weed

METHOD: Place pond weed in a beaker of water Change the independent variable Leave for 5 Minutes to allow pond weed to adapt to environment Count the number of air bubbles produced in a fixed period of time Increase or decrease the independent variable by a fixed increment (e.g, distance of lamp to change light intensity) Repeat process to obtain a range of data and analyse results

INDEPENDENT VARIABLES: LIGHT INTENSITY Use a lamp and change light intensity by adjusting the distance between lamp and pond weed CARBON DIOXIDE CONCENTRATION To increase Carbon Dioxide concentration, add Sodium Bicarbonate into beaker of Water To decrease Carbon Dioxide concentration, add Sodium Hydroxide into beaker of Water CHLOROPHYLL Use variegated plant - Green plant containing Chlorophyll, and White plant without Chlorophyll