Experiments - Photosynthesis

• Photosynthesis experiment


  • proves that plants do not get their food from soil
  • soil contains water and mineral salts but not carbon compounds

  
• Showing photosynthesis has taken place

  • glucose is always present in leaves
  • if starch is absent at the beginning of the experiment but present at the end, it shows photosynthesis has taken place

  
• Light in photosynthesis


  • test for starch

  
• carbon dioxide in photosynthesis


  • soda lime and potassium hydroxide absorb carbon dioxide

  
• gas produced during photosynthesis

  • sodium hydrogencarbonate provides dissolved carbon dioxide
  • test with glowing splint, if glowing splint reignites, gas is oxygen

  
• Effects of varying light intensity on rate of photosynthesis

  • independent : distance of light source from plant
  • sodium hydrogencarbonate solution provides dissolved carbon dioxide for photosynthesis
  • dependent : measure number of bubbles per minute

  
• Effect of varying carbon dioxide concentration on rate of photosynthesis

  • Independent : use different concentration of sodium hydrogencarbonate solution
  • dependent : measure number of bubbles per minute

  
• Effects of varying temperature on rate of photosynthesis

  • independent : temperature of water
  • dependent : number of bubbles per minute
  • sodium hydrogencarbonate solution should be changed for each temperature