Photosynthesis practical

Cards (20)

  • What should you be able to describe by the end of the video?
    Investigate light intensity's effect on photosynthesis
  • What should higher tier students explain regarding the results?
    How results are affected by the inverse square law
  • What equipment is used to start the experiment?
    • Boiling tube
    • LED light source
    • Sodium hydrogen carbonate solution
    • Pond weed
  • Why is an LED light source preferred in the experiment?
    It releases minimal heat affecting temperature
  • What is the purpose of the beaker of water when using a normal light bulb?
    To absorb heat produced by the bulb
  • What does sodium hydrogen carbonate solution release?
    Carbon dioxide
  • What should be observed from the cut end of the pond weed?
    Bubbles of gas being produced
  • How long should the pond weed acclimatize in the boiling tube?
    Five minutes
  • What gas is produced by photosynthesis?
    Oxygen
  • What is the procedure after starting the stopwatch?
    Count the number of bubbles produced in one minute
  • How many times should the bubble count be repeated?
    Two more times
  • What is the next step after calculating the mean number of bubbles?
    Repeat the experiment at different distances
  • What distances should the experiment be repeated at?
    20 cm, 30 cm, and 40 cm
  • What are the main problems with counting bubbles in the experiment?
    • Bubbles can be too fast to count accurately
    • Bubbles vary in size, affecting count consistency
  • How can the problems with counting bubbles be solved?
    Measure the volume of oxygen produced
  • What equipment is used to measure the volume of oxygen produced?
    Measuring cylinder
  • What happens to the number of bubbles per minute when the distance is doubled?
    It falls by a factor of four
  • What is the scientific term for the relationship between distance and light intensity in this experiment?
    Inverse square law
  • Why does light intensity affect the number of oxygen bubbles produced?
    Light is needed for photosynthesis
  • What should students be able to do after watching the video?
    • Describe the investigation of light intensity on photosynthesis
    • Explain the inverse square law effects for higher tier students