The diagram shows a small hydroponic system in a school greenhouse. Lettuce plants are supported above a tank containing water and dissolved mineral ions. A...
Question 1 Report
The diagram shows a small hydroponic system in a school greenhouse. Lettuce plants are supported above a tank containing water and dissolved mineral ions. A pump moves the solution past the roots. The student compares the growth of these plants with lettuce grown in soil in a similar area of the greenhouse.
(a) Describe how the system provides two requirements, other than light, for growth of the lettuce plants. [2]
(b) Explain why the student should use plants of the same species and similar starting mass in both growing methods. [3]
(c) Complete a suitable measurement the student could make after four weeks to compare crop yield.
Measure the total __________ mass of lettuce harvested from each growing area. [2]
Answer Details
(a) Roots receive water from the tank, and dissolved mineral ions are supplied in the water. The pump can also provide oxygenated solution around roots. [2]
(b) Different species can have different growth rates, and starting mass affects final mass. Using the same species and similar starting masses makes any difference in growth more likely to be caused by the growing method rather than those variables. [3]
(c) Measure the total fresh mass of lettuce harvested from each growing area. The areas compared must be the same size. [2]
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