Engineering explained!! Previous posts have highlighted mechanical engineering interview technical concept questions, which address fundamental principles, as well as brain teaser style questions, which test technical knowledge through unconventional applications. In between those two technical question types exists one more often asked type. It is not uncommon for interviewers to directly reference real-world engineering decisions and ask you to explain them. How is this stapler manufactured? Why are manhole covers round? How does a DC motor work? And many more.
These questions don’t always have a “correct” answer per say, and the interviewer is mainly looking to assess your technical creativity and ability to think inquisitively about engineering in the real world. This is an invaluable skill to have as an engineer in industry as for almost every product you design, some degree of inspiration will come from products that already exist. A sample real-world engineering question with a somewhat defined answer is…
Question: Why are there gaps between train tracks?
This is a relatively focused real-world question and can be effectively answered in a few sentences. The main technical concept to note here is thermal expansion (hence why those spaces between tracks are called expansion gaps). Because train tracks are exposed to fluctuating temperatures and climates, they expand (when heated) and contract (when cooled) over time. On a hot summer day in Texas, for example, expansion gaps allow the tracks to experience longitudinal strain while remaining in line with the adjacent track members. If tracks were placed flush against one another, the tracks would be at risk of a buckling failure due to thermal expansions with constrained ends, which could de-rail the train.
After noting the fundamental principle here, it can only further bolster your case if you can quickly think about adjacent details or other similar real-world examples to reference. For example, you could then note that expansion gaps are common in many structures, such as cracks on the sidewalk or gaps in the road at both sides of a bridge.
