Question 1 Report
| Light condition | Bubble moved (mm in 5 min) |
|---|---|
| Darkness | 2 |
| Dim light | 6 |
| Bright light | 11 |
The table records how far an air bubble moves in a potometer under different light conditions in 5 minutes. The data show that transpiration is fastest...
Light causes the guard cells to open the stomata, so more vapour can diffuse out and transpiration speeds up. The table shows the bubble moving furthest in bright light (11 mm) compared with dim light (6 mm) and darkness (2 mm), confirming that transpiration is fastest in bright light. In darkness the stomata tend to close, which is why the rate there is lowest.
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