BRAINCAKEInvestigating the Rate of Photosynthesis
The rate of photosynthesis can be measured by the rate at which a product is made (oxygen) or a reactant is used up (carbon dioxide). A common method uses an aquatic plant such as pondweed (Elodea or Cabomba), because the oxygen it releases can be collected.
In a photosynthometer, a cut piece of pondweed is placed in water containing sodium hydrogencarbonate (a source of carbon dioxide). The gas released collects in a capillary tube. After a set time, the gas bubble is drawn along the tube with a syringe and its length is measured against a scale. The volume of gas = πr2 × length. Counting bubbles is quicker but less accurate, because bubbles vary in size.
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
Key terms in this lesson
- photosynthometer
- Apparatus used to measure the rate of photosynthesis in an aquatic plant by collecting the oxygen it releases as a gas bubble in a capillary tube.
More in Energy for Biological Processes
- Limiting Factors of Photosynthesis
- Light Intensity as a Limiting Factor
- Carbon Dioxide Concentration as a Limiting Factor
- Temperature as a Limiting Factor
- Interpreting Limiting Factor Graphs
- Effect of Limiting Factors on the Calvin Cycle
- Uses of Triose Phosphate
- Agricultural Glasshouses and Limiting Factors
All 17 lessons in Energy for Biological Processes · All AQA A-level Biology topics