Science Questions

Why is my fridgeís magnetic door seal harder to open straight after itís only just been closed?

Sun, 19th Sep 2010

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Question

Ryan, Cambridge asked:

Why is my fridgeís magnetic door seal harder to open straight after itís only just been closed?

Answer

Dave -   Itís a lovely piece of physics, this one.  Basically, the magnetic door seal clips on and it makes a really good airtight seal.  That means that the fridge is full of fairly warm air from outside then over the next 2 or 3 seconds, that cools down.  When air cools down, it shrinks, so it reduces the pressure inside the fridge.  So to open that door now, you've got to pull against all that pressure difference and itís really difficult.  But if you leave it for a couple of minutes, there are few leaks in there, so the air slowly works its way back in and the pressure is equalised, so itís nice and easy to open again.

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