Photosynthesis Lab
See how the rate of photosynthesis depends on light intensity, carbon dioxide and temperature, and that the factor in shortest supply limits the rate.
Before you try
What if you gave a plant unlimited light? Would it keep making food faster forever?
Try it out
Interactive activity
Sign in to play
Use a Google account (yours or a parent’s) to unlock this simulator. We store only your name and email so your favourites and progress follow you.
Signing in needs an internet connection. Once you are signed in, simulators also work offline.
Free preview
Loading controls…
What happened?
Move a control to see what changes and why.
Only light, carbon dioxide and warmth are varied. A real leaf also needs water and nutrients, and it respires at the same time, using some of the oxygen back.
Something went wrong
This simulator could not load. Check your connection and try again.
Try these ideas
- Raise the light slowly. When does the bubble rate stop increasing?
- Now raise carbon dioxide. Does the rate rise again?
- Set the temperature very high. What happens to the enzymes?
Why it works
Photosynthesis is how plants make sugar from carbon dioxide and water using light energy, releasing oxygen: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. The green pigment chlorophyll captures the light.
Increasing light speeds photosynthesis, until something else runs short, such as carbon dioxide. Temperature matters too: enzymes work faster when warm but stop working if it gets too hot. The bubble counter shows the rate; the graph shows which factor is limiting.
Check your understanding
Question 1 of 3
Which gas do plants take in for photosynthesis?
Light is high but the rate stops rising. The most likely limiting factor is…
What happens to photosynthesis if the temperature gets far too hot?
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
For parents & teachers
- Put a water plant or leaf in a jar of water in the sun and look for bubbles.
- Ask: why are most leaves flat and wide?
- Discuss why greenhouses are warm and sometimes have extra CO₂.