Why do refrigerator doors suddenly need hulk strength to open at random times?
In: Physics
What mean by “random”?
When you open it, it fills with warm air. Once you close it, that warm air rapidly cools and therefore contracts, causing a vacuum pressure inside.
Pressure, volume, and temperature all are inter-related.
As temperature rises – the volume of space remains constant – and the pressure changes – all rapidly. And leading to a momentary suction.
About the pressure – when you have something the size of a fridge door you only need a very small pressure difference to add up to a very large force holding the door shut.
Say the door is 30” x 40” – that’s 1200in^2
Even 0.1psi pressure difference here adds up to 120 pounds holding the door shut
[removed]
[removed]
Refrigeration mechanic here saying that no fridge has a vacuum pump in it. What is actually happening here is the air inside the fridge is colder that the ambient air outside the fridge. The pressure temperature law explains how the hot external air is higher pressure than the cold internal air. This pressure difference means there is a negative pressure inside the fridge which holds the door shut. The reason it is random is it depends on how many times you open the fridge and also depends on ambient temperature. A larger difference in external and internal temperature will mean a stronger pressure difference.
Fridges have good seals.
Hot air takes up more volume than cold air.
Since the fridge volume can’t decrease, the airs pressure does.
As air cools, good seal makes vacuum.
Hotter the air that gets into the fridge (or colder setting on the fridge) stronger vacuum.
Latest Answers