By Jim Davis
You are probably wondering what in the world a question like that would have to do with a job interview. Well, you may be asked any number of different types of questions, and there are lots of reasons.
The "why are manhole covers round?" question is one I have seen used in practice interviews, but to be honest, I've never had it asked in a real interview. If it were, though, it would be basically to find out several things. One could be just to see how you react to an "off-the-wall" kind of question. Do you get flustered, or do you keep your cool? Another reason is to see how well you can think. What your answer is may not be as important as how you come up with it and how you state your answer.
Other questions interviewers will ask you probably fall into five basic categories:
- Your qualifications for the job.
- They may ask something about your grades, courses you took, etc.
- Your experience.
- Your opinion of yourself.
This is no time to be bashful or to put yourself down. That does not mean you should claim to be able to do things you can't do, of course, but showing that you feel good about yourself and your abilities is a must. - "Dumb questions."
This is probably the place where the "manhole cover" question would fit. Questions like this are to see what kind of answer you will come up with, and to explore why you answered the way you did. And, as you've probably guessed by now, these questions are NOT dumb. They are basically to see how you think. - "What did you do?" or "How did you do that?" questions.
These questions are to see how you actually behaved in real situations. They may not have anything to do with any kind of work you have done, though. Something you have told about during the interview, or something you put on your resume will give them an idea for this type of question.
Regardless of what kinds of questions your interviewer asks, though, you should always remember this. They are hoping that you will do well in your interview. After all, their reason for interviewing you is to find the best person for the job. That person might as well be you.
Microsoft reportedly used this question months before this Feb.2009-dated item was posted.
ReplyDeleteSee http://en.wikipedia.org/wiki/Manhole_cover
manhole covers are round so that they won't fall into the hole when removed.
ReplyDeleteManhole covers are round because manholes are round.
ReplyDeleteTechnically the answer to why manhole covers are round is round cover manholes are for plumbing like swerage, drainage., whereas the square ones are for electrical services manhole. for identity purposes its shape is selected.
ReplyDeleteMany other related interview questions at http://www.technical-interview.com
ReplyDeleteOk, I had this asked in an interview 8 years ago. my answer was so that people could get in easier.
ReplyDeleteI was interviewing for a position at an investment bank in toronto. The interviewer told me my answer was wrong its so that "they don't fall in". I said he was wrong, left and decided to go back to the family business.
See, my family is in Heavy civil construction I've been around MH's my whole life. MH's dont fall in because there is a lip on the inside of the circular frame that is cast when the frame is made. Thats why the grate doesnt fall in (IDIOT interviewers).
Further MH covers come in many shapes (round, square and yes even triangle)
So NO its not that so they dont fall in and NO its not to identify utilities bc MH's were around before electricity (even though they might ID utilities today thats not why they became round).
Stupid interview questions are just that STUPID.This particular question was asked to see how people answer. There is no definite answer. The problem is people dont know HOW to interview. They pick up a book "100000000 interview questions" and right away they become master interviewers, what a joke.
Anyway i'm glad this happened to me because i saved myself from becoming a mindless idiot in the rat race for supremacy in the cubicle monkey kingdom.
The answer by the way - Probably, (b/c no one knows for sure) the ancient Greeks and Romans found the circle was able to hold more load than any other shape. a circular(spherical) chamber was able to withstand the compression forces underground greater than other shapes while at the same time using the least amount of material than any other shape. So they made the manhole lids rounds round because they used less material and a human being in plan section is roughly circular
It doesn't mean to stop it falling in from rest, it is so if it was dropped in diagonally, for example, the circular manhole cover would have the same width, whereas a square or rectangle would have a much reduced width and be able to fall into the hole, the lip has nothing to do with it.
ReplyDeleteAlso your argument for it being round because of amcient greeks and romans is a little off, it could explain why the tubes are round, but the manhole cover dosn't experience pressure on its rounded edge, or at least very little, it only has pressure on its top and bottom face, which are both flat regardless if its a triangle, square, or circle etc.
Except for the not falling in argument, the most realistic I've heard is that they're round so that they can roll, anyone removing a manhole cover simply tilts and rolls it away, rather than having to lift the "hole" (haha) thing and carry it off as would be necessary if it wasn't circular.
Manholes DO have pressure on its rounded edge. They experience soil loads as well as hydrostatic pressure. I should know, I design them. Circular manholes tend to be used because both the lateral and longitudinal pressures are more evenly distributed and therefore are able to handle higher loads with less material. They do not make covers circular so the the covers don't fall in. The covers don't fall in because it's size is uniform and cannot get past the LIP. It's a bonus benefit of the shape.
ReplyDeleteI couldn't even start to tell you why a manhole cover is round. I simply accept that it is. Much as I accept that socialising with tedious relatives is part of celebrating Christmas or answering stupid questions is a traditional part of an interview.
ReplyDeleteFine, the question's designed to assess your reasoning skills but surely you'd want to get an idea of your candidate's reasoning skills in context? Why not give them a hypothetical scenario, related to the job and see how they get on with that?
Up 'til now, I've only ever had the "traditional" stupid questions and rattled off the "traditional" pre-packaged answers. But my sister got hit with this one during her graduate jobs hunt:
"Which character from Friends would you be?"
Fantastic. Animal/mineral/vegetable, fine, if you really have to. But a franchise? Suppose, just suppose, that the candidate hasn't watched it?
My sister hadn't watched it. Still hasn't. She told the interviewer as much and then asked how it pertained to the job. She was shown the door fairly quickly but I think that was her main aim after that question.
you'd think they would be interested in people who didn't watch mindless drivel. That being said, I've been pushed out of positions I was doing well in because I didn't read the same pointless books and magazines as the idiot I worked for and her brown nosing women. The book I reference is "The Secret" and there is no secret to a bunch of idiots being ripped off because they are materialistic jerks.
ReplyDeleteThe good news is that there IS justice in the world - they got bought out by AT&T and their lives are now hell. What was the secret to THAT? Hahaha.
Thanks for posting info and your sources. I've worked at Microsoft as a consultant here and there for years. Never as an employee nor interviewed for a direct hire though.
One recent Microsoft manager I worked with told me he asks people "how would you design an in dash (car) coffee maker and how would it work?". Another Microsoft question I was asked was "Tell me what you'd design for alt+tab and how". That one got me. Oh well.