Why Are Fridge Doors Hard To Open Immediately After They Are Shut Close?

This hot afternoon, I went to the freezer to take some water. I opened the door of the refrigerator, took out a bottle of chilled water and shut the door. I quickly poured out enough cold water into a glass cup and then tried to replace the bottle back in the fridge but the fridge door refused to budge. It was shut tight like as tho locked with a key and no matter how hard i pulled it was useless. Many of us have had such exp with our refrigerators at home and we all soon learnt that we have to wait for some time (say 30-40seconds) before the door opens with ease again. Now the question is, what is the principle behind this process?
A good physicist here should be able to give a convincing explanation thereafter.

Note : When the pressure between the inside of a container and its outside are pretty much same, you feel no resistance opening the lid or door to that container, as the case may be. When there is differential pressure between the inside and outside, then there is resistance. The direction of differential pressure will determine where resistance is coming from. Because the fridge is much colder than the outside, it is at a lower temperature. Remember the relationship between temperature and pressure? It's a direct relationship. If the temperature inside a container is really low, the gas particles in that container dont move rapidly, which means they are sluggish. That translates to lower pressure. Think about a cooking gas container; its gas particles are bouncing all about the container looking for an escape, which is why when you create an outlet, they immediately rush out. These gas particles are at a higher pressure. Anyways, I digress.

Back to the explanation, the lower temperature inside the fridge means the gas (air) particles inside the fridge have created a lower pressure situation inside it, lower than the atmospheric pressure (which is the pressure at room temperature). Because there is now differential pressure, when you try to pull the fridge open, there is resistance. But why is the resistance against opening the fridge? Because matter in the classical world generally tends to move towards lower pressure. This is the same reason your gas particles in the cooking gas (which are at higher pressure) are seriously looking for a way to escape. So, your fridge door continues to resist your pull because the door is gravitating towards the lower pressure in the fridge.
The small seal areas on the door lip make this pressure translate into greater force and that's why you often need to pull hard to open the door.

Posted: at 13-03-2016 02:48 PM (8 years ago) | Addicted Hero

av know why long ago...

Posted: at 19-03-2016 09:43 PM (8 years ago) | Hero

See question

Posted: at 10-06-2016 10:45 PM (7 years ago) | Gistmaniac

Thanks for such an interesting post. To be honest, I have never encountered such a problem before. My refrigerator works at about 40% of its capacity, so I probably haven't encountered such a problem before. For the entire time, while I have a refrigerator at home, I had only one problem with it. The fact is that it is located near the front door. Due to the fact that the refrigerator is very close, the door was constantly collecting moisture due to different temperatures and over time it began to rust. I had to purchase a new door from https://doordesignlab.com/interior-doors/stile-and-rail.html as well as move the refrigerator so that this problem does not recur in the future.

Posted: at 1-11-2020 05:35 AM (3 years ago) | Newbie