BiologyGrade 10Plants and Biochemical Molecules

Photosynthesis Lab: Light, CO2, and Oxygen Rate

Adjust light intensity, carbon dioxide, temperature, water supply, and leaf area to measure photosynthesis rate and oxygen production.

SimulationsLab index
Textbook unitPlantsGrade 10 Biology Unit 2 and Biochemical Molecules reference
Keywordsplants, photosynthesis, light, carbon dioxide, oxygenMapped to available textbook headings
Practice modeManipulate, measure, explainUse the controls, then read the live evidence

Biology · Grade 9

Find the limiting factor in photosynthesis

Tune light, carbon dioxide, temperature, water, and leaf area to measure oxygen output and glucose production in a plant leaf.

Limiting factorCO2
1

Drag the sun ↓ toward the leaf to add light. Watch O2 bubbles increase. Then max out light — does raising CO2 still help? (Blackman's Law: only the weakest factor matters)

2

Set light to max. Now CO2 is limiting — slide it up and see the rate climb. When does raising light alone stop helping?

3

Max out light and CO2, then change temperature. Find the sweet spot (~28°C). What happens above 40°C? Why does the rate crash?

70%
Chloroplast activity
CO2520 ppm
H2O68%
Temp26°C
O2 output31.5 units/minHigh production
Light factor69%
CO2 factor60%
Stomata opening97%
Photosynthesis insight

Blackman's Law: CO2 (60%) is the most limiting factor — rate is 26.67 units/min. Improving any other input won't raise the rate until CO2 is addressed.

Photosynthesis rate26.7 units/min
Oxygen output31.5 units/min
Glucose made19.2 mg/min
Temperature factor98%
Water factor97%

Lab task

Raise photosynthesis above 20 units/min, then lower one input until it becomes the limiting factor. Record both trials.

Observation rule

Photosynthesis rises only when the limiting factor improves. Once one input is scarce, extra amounts of other inputs have little effect.

Mission

What to prove in this lab

  1. Identify the limiting factor that controls the photosynthesis rate.
  2. Relate light, carbon dioxide, water, and temperature to oxygen output.
  3. Use live measurements to compare plant productivity under different conditions.