1st method ( photosynthesis practical)

• 1. Clamp boiling tube and add sodium hydrocarbonate as it encourages pondweed to photosynthesis by releasing carbon dioxide in solution
• 2. Put pondweed right below the level of sodium hydrocarbonate
• 3. Using dissecting scissors, snip the very end of pondweed for steady stream of oxygen bubbles
• 4. Count number of bubbles
• What is is better to use as a light source and why?

  LED light as it doesn’t release heat
• 5. Align light source to 10cm and allow pondweed to adjust
• 6. Time for 1 minute and count number of bubbles
• 7. Move light source away by 10cm and allow pondweed to adjust to the new light level
• 8. count number of bubbles
• 9. Move light away again by 10cm and repeat the experiment 3 more times and count bubbles