Question 8
FA student uses a potometer to investigate the effect of air movement on the rate of water uptake by a leafy shoot.
The Figure shows the potometer.
Figure
The student measures the distance the air bubble moves in 5 minutes. She does this three times in still air and three times with a fan blowing air over the leaves.
The Table shows her results.
Table
| Condition | Distance in trial 1 in mm\text{mm}mm | Distance in trial 2 in mm\text{mm}mm | Distance in trial 3 in mm\text{mm}mm | Mean distance in mm\text{mm}mm |
|---|---|---|---|---|
| still air | 18 | 22 | 20 | 20 |
| fan | 42 | 47 | 43 |
a.[1]
Calculate the mean distance moved by the air bubble with the fan.
b.[1]
Calculate the rate of water uptake with the fan.
Use your answer to (a).
Give your answer in mm\text{mm}mm per minute.
c.[3]
Explain why the fan increases the rate of water uptake.
d.[2]
Give two precautions the student should take when setting up the potometer.
2.2 The challenges of size Questions
114 exam-style questions on OCR GCSE Biology 2.2 The challenges of size, covering 2.2.1 Exchange surfaces and surface area : volume ratio, 2.2.2 Substances transported in organisms, 2.2.3 The human circulatory system, 2.2.4 The heart and blood vessels, 2.2.5 Red blood cells and plasma, 2.2.6 Uptake of water and mineral ions by plants, 2.2.7 Transpiration and translocation, 2.2.8 Xylem and phloem, 2.2.9 Environmental factors and water uptake, and 2.2.10 Using a potometer. Each one has a worked solution and a mark scheme showing where the marks go.