Edexcel IGCSE Biology 复习笔记 2.5.3 Practical: Investigating Photosynthesis & the Evolution of Oxygen

• We can demonstrate the evolution of oxygen (from the process of photosynthesis) using water plants such as Elodea or Camboba - types of pondweed
• As photosynthesis occurs, oxygen gas produced is released
• As the plant is in water, the oxygen released can be seen as bubbles leaving the cut end of the pondweed

Apparatus

• Beaker
• Water plant
• Funnel
• Boiling tube
• Splint
• Bunsen burner (for the oxygen test)
• Heat proof mat

Method

• Take a bundle of shoots of a water plant
• Submerge them in a beaker of water underneath an upturned funnel
• Fill a boiling tube with water and place it over the end of the funnel
• As oxygen is produced, the bubbles of gas will collect in the boiling tube and displace the water

Results and analysis

• Show that the gas collected is oxygen by relighting a glowing splint

Experiment to show the evolution of oxygen from a water plant

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