Transcript Photosynthesis Equation

Photosynthesis Equation
D. Crowley, 2008
Photosynthesis Equation
To know the equation for photosynthesis
Weight Gain
• How can a plant put on weight?!
• Plants make their own food via photosynthesis (chlorophyll in the
leaves) with the energy coming from the Sun
light energy
carbon dioxide
(from the air)
water
(from the soil)
chlorophyll
glucose
oxygen
Photosynthesis
chlorophyll
light energy
carbon dioxide + water  glucose + oxygen
6CO2 + 6H2O  C6H12O6 + 6O2
Photosynthesis
Experiment
• How could you design an experiment proving that sunlight is
needed for photosynthesis?
• Set up an experiment using 3 Petri dishes containing some damp
cotton wall with cress seeds in
– Black one out completely (with dark paper)
– Have one slightly covered (with tracing paper)
– Have one clear (covered with cling film)
Dark paper
Tracing paper
Cling film
Prediction
• Once you have set up your experiment, predict what you will find
and why
• Photosynthesis requires carbon dioxide, water, and light to occur
• In this experiment we have kept the carbon dioxide and water
the same - only the light levels have changed
Prediction
• We should find that when there is insufficient light
photosynthesis will not take place, and the cress seeds will not
grow (when placed in the dark Petri dish)
• The cress should get some light with the tracing paper, so should
grow a little
• The cress with the clingfilm should have sufficient
light to grow normally
Word Equation