Understanding Vacuum Physics and the Crack in My Window

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Discussion Overview

The discussion revolves around the potential causes of a crack in a double-pane window following the slamming of a door in a small room. Participants explore the role of vacuum forces, air pressure, and the mechanics of glass under stress, focusing on both theoretical and practical aspects of vacuum physics and material properties.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions whether a vacuum force could have caused the glass to crack, suggesting that air pressure changes due to the door's movement might be more relevant.
  • Another participant argues that the air pressure in the room is not sufficient to break the glass, implying that the force from the slammed door propagates through the walls instead.
  • Some participants propose that while the door slamming could contribute to the issue, it would require significant force to crack the glass, and they express curiosity about the room's construction materials.
  • There is a suggestion that the glass's stability and design, particularly in double-pane windows, would make it resistant to cracking from pressure alone.
  • One participant posits that vibrations or defects in the glass's fabrication could be responsible for the crack, rather than direct pressure from air or the door slamming.

Areas of Agreement / Disagreement

Participants express differing views on the likelihood of vacuum forces causing the crack, with some asserting that air pressure changes are more significant while others emphasize the role of vibrations and potential defects in the glass. No consensus is reached regarding the primary cause of the crack.

Contextual Notes

Participants note various assumptions about the room's design and the properties of the glass, as well as the mechanics of door slamming and air pressure dynamics. The discussion highlights the complexity of the interactions involved without resolving the underlying uncertainties.

slworry
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Vacuum Physics?

I would like some clarity on a problem I think is attributed to a vacuum space. This is what happened...I have a small room that is 7' x 10', there are two metal doors directly across from each other on opposites sides of the room. It seems that when I want to close the door fast the air within keeps the door from closing but I can close it if I do it slowly. My problem is that my daughter slammed the door with significant force and it did close, however there are double pane windows in that room as well and one of the windows now has a crack in it (the inside side of the double pane glass---inside the room). Could the vacuum force when she slammed the door caused the glass to crack?
 
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slworry said:
I would like some clarity on a problem I think is attributed to a vacuum space. This is what happened...I have a small room that is 7' x 10', there are two metal doors directly across from each other on opposites sides of the room. It seems that when I want to close the door fast the air within keeps the door from closing but I can close it if I do it slowly. My problem is that my daughter slammed the door with significant force and it did close, however there are double pane windows in that room as well and one of the windows now has a crack in it (the inside side of the double pane glass---inside the room). Could the vacuum force when she slammed the door caused the glass to crack?

A vacuum doesn't exert a force on anything.

I presume the door opens outward? If so then it sounds more like air is being drawn/forced into the room by the closing door and thus creating an overpressure in the space.

CS
 


from my POV, that's quite a silly prediction, there's air in the room , the air pressure does not seem sufficient to break the panes though(the one who designed the room must know, decrease in the area of the pane and increase in the area of the room decreases the force on the pane), the force of the slammed door propogated through the walls
 
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vin300 said:
from my POV, that's quite a silly prediction, there's air in the room , the air pressure does not seem sufficient to break the panes though, the force of the slammed door propogated through the walls

The door slamming could certainly also cause the problem...but I imagine that the door would have to be slammed really hard to crack a pane of glass. I suppose it would help to know the composition of the room (e.g. walls, windows, doors).

CS
 


vin300 said:
from my POV, that's quite a silly prediction, there's air in the room , the air pressure does not seem sufficient to break the panes though(the one who designed the room must know), the force of the slammed door propogated through the walls

The air in the room is at atmospheric pressure, the air outside of the room is as well. If the pressure inside the room is increased enough, then the unbalanced air pressure on the inside could certainly crack the pane of glass. Hence, it's not that silly.

CS
 


stewartcs said:
Hence, it's not that silly.

CS
My post was addressed to the OP. When I was doing it, there wasn't yours
 


I doubt that the glass would crack, from the pressure. Glass is very stable and it is pretty much impossible to break it with an even force like a pressure wave of a few millibar. The force is very even. With double pane windows it is almost impossible since these already have lowered pressure in between the panes so they are build to withstand substantial pressure.

When the glass breaks from the slamming of a door, it is most likely caused by vibrations, or fabrication defects. If the glass is mounted unevenly a pressure point might cause a crack, and once double paned glass windows get a crack they break over a large area, due to the pressure difference (I talk from experience). So yes slamming a door might break a window but not directly, only through shaking it somehow.
 

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