Engineering is another one of those tricky interview subjects where candidates can be especially nervous, as many fear they do not have enough technical knowledge of the subject to succeed. But fear not – admissions tutors are fully aware that your A-level teaching will not have covered the subject comprehensively – they are looking for how you might respond to teaching in future and how you use your brain and logic to respond to engineering problems as they are presented to you. This week’s genuine Oxbridge interview question comes from Byron Byrne, of the Department of Engineering Science at Oxford University. “How would you design a gravity dam for holding back water?”
One Step at a Time
The most dangerous pitfall with this question is to try to answer it outright rather than approaching it gradually, one step at a time. Byrne explains that the most successful candidates will first try to determine the forces acting on the dam in order to consider the “stability of the wall under the action of those forces”. So remember, it is often important to turn the question on its head – the answer can’t be given until you have worked out the conditions under which it will operate. Always consider the forces acting on a structure first before proposing potential structural decisions.
It sounds strange, but candidates are often so nervous and so keen to impress at interview that when asked a design question like this one they jump straight to solutions and ideas, when what the interviewer is actually looking for is an awareness or an ability to hypothesise areas in which the project might fail. In this case it is important to acknowledge that the force of the water might be too great, causing the dam to fall, or that other problems like sliding, structural faults, or water seeping beneath the dam may occur. The best engineers will approach a design problem by considering every aspect of the potential outcome, with possible failure and potential problems an integral part of the planning process. Only once you have considered all the ways in which you might fail may you offer a solution that is capable of addressing these issues.
Byrne acknowledges that much of the expertise necessary to answer this question will not have been taught at A-level, but says that seeing whether a candidate shows real enjoyment and enthusiasm for this kind of engineering puzzle is just as important in determining interview success. So remember, the way you approach the question, how well you absorb new ideas when the interviewer offers them to you and how positively you engage with the discussion are all as important as prior knowledge.
Using maths and physics and applying them to specific design and engineering problems are major skills that the interviewer will be looking for. It doesn’t matter if you aren’t quite sure what the right mathematical expressions or physics formulae are, or exactly how to apply them to the problem – the main thing is to show that you are trying. It is much better to suggest a potential use of maths or physics to help solve the problem than to keep quiet because you aren’t sure what would be the right thing to do. Byrne hopes that having acknowledged the potential for the water to push the dam over, candidates would then “construct simple mathematical expressions to predict when this would occur”.
Above all remember that in these subjects where you may not have a great deal of prior knowledge, the interviewer will always be ready to help and point you in the right direction. Asking for help or admitting you don’t know will not count against you, but a bad attitude, disinterest or lack of trying will.