What if I ask a "what if" question? What are the criteria for the question not to be closed? The question should be about physics. That's clear. The question shouldn't be completely random too. For example:

-What if a massive ball hits my sleeping room wall?


-What if a massive ball (radius 10, mass density 0.5,) hits the wall of my sleeping room (area 25, thickness 5, mass density 1) perpendicular in the right upper corner with a velocity 50?

Or more abstract:

-What if a sphere with mass with radius $R$ density $\rho$ and velocity $\vec{v}$ hits a wall with area $A$, thickness $d$ and density $\rho$, in the middle?

Could be instructive if you specify the strength of the wall too.

What about random situations? You can imagine rotating spheres (no matter how they acquired the rotation) hitting with friction another sphere, you can imagine cubes hitting Earth in sea or in the desert, you can imagine whatever. You can make abstractions of the situations: a solid ball of helium on the bottom of the deepest sea becomes a solid ball of helium inside a spherical volume of water at $250(K)$. But when are the abstractions instructive?

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    $\begingroup$ Those questions have the same problem as "is it possible?" questions in that the expected answers will be vague because the question itself is vague, even if the question has lots of details to make it seem specific. They aren't seeking a specific explanation about anything. They just present a scenario...and then what? They also show a lack of effort on the part of the questioner, I think. $\endgroup$
    – DKNguyen
    May 30, 2021 at 23:52
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    $\begingroup$ From What types of questions should I avoid asking?: avoid asking subjective questions where … you are asking an open-ended, hypothetical question: “What if ______ happened?” $\endgroup$
    – G. Smith
    May 30, 2021 at 23:56
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    $\begingroup$ What if I ask a "what if" question? You can expect some members to downvote, and vote to close. $\endgroup$
    – G. Smith
    May 30, 2021 at 23:58
  • $\begingroup$ What are the criteria for the question not to be closed? That fewer than five members, or one moderator, think it should be closed. $\endgroup$
    – G. Smith
    May 31, 2021 at 0:02
  • $\begingroup$ @G.Smith That "mindless social fun" part really stands out to me. I remember answering a bunch of "what if" questions in front of a classroom of elementary students while we were trying to buy time to set up an experiment. And a lot of "what if" questions sound just like the ones they were asking. But some were better constructed than your typical "what if" question. It doesn't take much. They just proposed a possible result which gave direction as to what the student was expecting in the answer: "If you shone a giant laser at someone's eye, would it explode?" was one of them. $\endgroup$
    – DKNguyen
    May 31, 2021 at 0:06
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    $\begingroup$ In my opinion, the OP’s question Why aren't my questions marked as hot? is relevant. What-if questions are HNQ bait. They may not be more likely to make the HNQ list, but if they do, they attract lots of attention. $\endgroup$
    – G. Smith
    May 31, 2021 at 0:14
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    $\begingroup$ Reminder: this is not a feature request post, so down votes shouldn't be used to to indicate that you think what if questions are bad. I think this is a valid meta question, so I don't think it should be down voted. $\endgroup$ May 31, 2021 at 11:31
  • $\begingroup$ Related question: How about a what-if tag? $\endgroup$ May 31, 2021 at 11:41
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    $\begingroup$ Related (up voted) question: Are outlandish XKCD style What If questions welcome here? $\endgroup$ May 31, 2021 at 11:43
  • $\begingroup$ @G.Smith As you pose it seems as if I want my questions to be hot. Now, I like it if they are, but frankly, I don't give a donder. I have seen hot questions being hot when they had 25 viewers. I'm interested in the mechanism behind a qeustion being hot or not. $\endgroup$ Jun 1, 2021 at 14:27
  • $\begingroup$ It’s a “what if” question about “what if” questions. If that isn’t meta, I don’t know what is! $\endgroup$
    – Brick
    Jul 4, 2021 at 1:13

1 Answer 1


If the post was just "what if _____ happened?" then that is way too broad. This is even mentioned in the help center for What types of questions should I avoid asking?. Additionally, the answers to such questions don't typically need to refer to any physics. Someone could say what actually would happen, and they technically would have answered the question.

If additional qualification way included that narrowed the scope to focus on the single physics concept that was bringing confusion, then that would be a lot better and give the question a better chance of being on topic. Though, at that point you might as well have the question ask about the physics concept directly rather bring in a hypothetical "what if?" scenario.


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