Question 1
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels meanA student uses a potometer to investigate the effect of wind speed on the rate of transpiration. Describe how the student could do this.
Show mark scheme for question 1
- place a fan at different distances from the leafy shoot / use different fan speeds (1)
- measure the distance moved by the air bubble in a set time (1)
- keep other variables the same, for example temperature / light / same shoot (1)
- repeat and calculate a mean (1)
Question 2
Supplement (what this means)
Supplement: only for the Extended papers (2 and 4). Core students can skip it. What the labels meanIn a potometer experiment, an air bubble moved the distances shown in the table. Calculate the rate of water uptake with the fan on, in mm / min.
| conditions | distance moved by bubble / mm | time / min |
|---|---|---|
| still air | 18 | 6 |
| fan on | 54 | 6 |
Show mark scheme for question 2
- rate = distance ÷ time = 54 ÷ 6 (1)
- 9 mm / min (1)