Question 15
Explain why an engineer would recommend solar-powered water pumps for crop irrigation to a community in a developing country. For three different types of technology knowledge, identify two factors of each to support your explanation.
Three types of knowledge with two factors each make six reasons, and each reason is one mark
Watch sunlight drive a pump that lifts water from a bore to the crops. Each new factor is a reason the engineer would recommend it, and the tally fills two boxes per type.
Every factor is a reason for solar pumps in this community. A reason against some other pump does not answer the question.
Build the answer one sentence at a time and watch the marks
Tap a sentence to add it to your answer, and tap it again to take it out. The marking guide ticks each dot point your answer earns. The 2026 syllabus allows up to 150 words per question, so the counter keeps you honest.
Nothing written yet. Start with an environmental factor.
Work through the solution one mark at a time
Write your own sentence for each step before you reveal it. The quoted wording is QCAA’s sample response.
Name the type of knowledge, then the factor, then why it favours solar pumps.
“The engineer would have considered the local environmental conditions. Effective use of solar energy requires that most days are cloud free. This would allow the solar-powered pumps to operate efficiently.”
- available sunshine, i.e. cloud-free proportion of days
- relating overcast conditions to operational efficiency.
Marker: explains appropriately using … 1 relevant environmental factor
The second environmental factor turns a weakness into a reason. The pump slows exactly when the crops need it least.
“On overcast, cloudy days when rain is likely, the solar pumps would operate less often, saving water.”
Marker: explains appropriately using … another relevant environmental factor
A factor can cut against the recommendation and still earn the mark, as long as you weigh it.
“The engineer would also have considered the economics of the use of solar water pumps. The initial cost of the pumps is possibly high when compared to other methods…”
- initial set-up costs
- running costs
- operational efficiency.
Marker: explains appropriately using … 1 relevant economic factor
The running cost answers the set-up cost.
“…but running costs are low, which allows the community to transport water cheaply and efficiently.”
Marker: explains appropriately using … another relevant economic factor
Can the water source keep up with the pump?
“It would be important to have a sustainable water supply, as solar pumps are able to supply large volumes of water.”
- water resource
- mechanical maintenance
- social impacts, i.e. improved quality of life.
Marker: explains appropriately using … 1 relevant sustainability factor
Can the community keep the system running?
“The engineer would have considered the sustainability of the solar pumps and the irrigation system, as breakdowns in the system would need to be repaired. This aspect of implementation of any mechanical system would need to be considered in the maintenance of the system.”
The engineer would have considered the local environmental conditions. Effective use of solar energy requires that most days are cloud free. This would allow the solar-powered pumps to operate efficiently. On overcast, cloudy days when rain is likely, the solar pumps would operate less often, saving water.
The engineer would also have considered the economics of the use of solar water pumps. The initial cost of the pumps is possibly high when compared to other methods, but running costs are low, which allows the community to transport water cheaply and efficiently.
It would be important to have a sustainable water supply, as solar pumps are able to supply large volumes of water. The engineer would have considered the sustainability of the solar pumps and the irrigation system, as breakdowns in the system would need to be repaired. This aspect of implementation of any mechanical system would need to be considered in the maintenance of the system.
At 156 words this sample is over the 2026 limit of 150. The six-sentence answer in the builder earns the same 6 marks in fewer words.
Marker: explains appropriately using … another relevant sustainability factor
Each phrase of the question gave you something
The 2020 subject report used this question as its example of students overlooking key information. A number explained at length why wind-powered pumps might not be suitable, which did not give a properly structured explanation of why the engineer would recommend solar pumps.
You have to choose the three types of knowledge yourself and then hold six separate reasons together around one recommendation. QCAA reported that the 2020 written section had exactly one complex familiar question, worth 6 marks, without naming it. Questions 14 and 15 were the only 6-mark written questions, and this one reads as the complex familiar one because the other, the logic question, asked you to read a given circuit into a truth table.
If I had to guess where you might lose marks, it would be writing about the pump you are not recommending, exactly as the subject report describes, or giving three factors of one type and one of another. Two per type is the rule. For 2026 the question has moved on: since 2024 it names materials science, mechanics and control technology as the domains, so read which trio you are given. The habit this question teaches, one sentence per factor in a fixed count, transfers directly.
Only mark this done when you could do it without help. Reading the solution does not count.
Question wording, any figures and marking-guide steps are from the 2020 QCAA Engineering external assessment, © State of Queensland (QCAA) 2020, licensed under CC BY 4.0, and have been adapted, except where a third-party source is named. Tangent Tuition is not affiliated with the QCAA.
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