Teacher Notes

Recap the equation for photosynthesis. Do this visually by showing students test-tubes of carbon dioxide, water, oxygen and glucose (tests for the first three substances can be reviewed if appropriate). Then review the differences between this process and respiration.

Ask students to label a diagram of a plant cell and review their functions.

Students could then count the numbers of bubbles of oxygen produced by Cabomba or Elodea pondweed at varying intensities of light. Encourage students to prove the gas they have collected is oxygen by using it to relight a glowing splint.