1. Photosynthesis Experiments
Gr C: Explain the variables involved with each practical.
Gr B: Summaries each experiment.
Gr A: illustrate the set up of each experiment.
Entrance Activity
Define the term “limiting factor” and list three limiting factors affecting photosynthesis.
Key Terms
Independent variable
Dependent variable
Controlled variables
Hydrogencarbonate indicator
Iodine
Strach

2. Learning Activity
Around the room are four different experiments relating to photosynthesis. Each experiment is vitally important and could potentially appear on your IGCSE examination. Therefore, you need to record as much information as possible about each experiment.

3. Learning Activity
As you move round the class room and look at each of the experiments, ensure that you complete the student hand out on your way round.

4. New Chemical Indicator Hydrogencarbonate indicator solution
Hydrogencarbonate indicator solution responds to changing carbon dioxide levels in the environment. This can be used to see whether or not a plant requires Carbon dioxide for photosynthesis
CO2 levels decrease
(pH rises)
Starting colour
CO2 levels increase
(pH drops)

5. Hydrogen Carbonate indicator
Learning Activity
Hydrogen Carbonate indicator
Independent variable:
Light Levels
Dependent variable:
Rate of photosynthesis
(measured by CO2 change)
Control variables:
Leaf size (mass)
Volume of indicator
Indicator starting colour
Volume of air in test tube
Activities
Identify the different variables in the experiment shown above.
Illustrate the set up of the experiment in your books.
Make a prediction of what the test tubes will look like after three hours.