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B2: Quiz 20
B2: Quiz 20
1) What are the four factors that affect the rate of transpiration?
2) A potometer measures the rate of water uptake by a plant. Due to transpiration streams, we can assume that the rate of water uptake is directly proportional to the rate of transpiration. A diagram of a potometer is shown below.
2) A potometer measures the rate of water uptake by a plant. Due to transpiration streams, we can assume that the rate of water uptake is directly proportional to the rate of transpiration. A diagram of a potometer is shown below.
a) Describe how we cut the plant for the potometer. Say two points.
b) How can we move the location of the air bubble?
c) If there is a fast rate of transpiration, will the air bubble move a small distance or a large distance?
d)
i) A student completes an experiment using a potometer. She leaves the plant for 5 minutes and the air bubble moves 13 mm. Calculate the rate of water uptake/ transpiration. Give the units for your answer.
ii) The student then changes the conditions and leaves the plant for 2 hours. After the 2 hours, the air bubble has moved by 25 cm. Calculate the rate of water uptake/ transpiration. Give the units for your answer.
3) A student uses a potometer to investigate how transpiration changes throughout a morning. He leaves a potometer (like the diagram in question 2) outside and measures the rate of water uptake/ transpiration for the following time frames (24-hour clock):
When would you expect the rate of water uptake/ transpiration to be the greatest? Explain your answer.
4) A student wishes to investigate how light intensity effects the rate of transpiration in a lab. He uses a lamp and completes the experiment with the lamp quite far away from the plant. He then moves the lamp closer to the plant and completes the experiment again. What does the student need to ensure about the lamp that he uses? Explain your answer.
5) How can we modify the potometer experiment to investigate the effect that air flow has on the rate of transpiration.
b) How can we move the location of the air bubble?
c) If there is a fast rate of transpiration, will the air bubble move a small distance or a large distance?
d)
i) A student completes an experiment using a potometer. She leaves the plant for 5 minutes and the air bubble moves 13 mm. Calculate the rate of water uptake/ transpiration. Give the units for your answer.
ii) The student then changes the conditions and leaves the plant for 2 hours. After the 2 hours, the air bubble has moved by 25 cm. Calculate the rate of water uptake/ transpiration. Give the units for your answer.
3) A student uses a potometer to investigate how transpiration changes throughout a morning. He leaves a potometer (like the diagram in question 2) outside and measures the rate of water uptake/ transpiration for the following time frames (24-hour clock):
- 5:00-6:00
- 8:00-9:00
- 11:00-12:00
When would you expect the rate of water uptake/ transpiration to be the greatest? Explain your answer.
4) A student wishes to investigate how light intensity effects the rate of transpiration in a lab. He uses a lamp and completes the experiment with the lamp quite far away from the plant. He then moves the lamp closer to the plant and completes the experiment again. What does the student need to ensure about the lamp that he uses? Explain your answer.
5) How can we modify the potometer experiment to investigate the effect that air flow has on the rate of transpiration.