how do things suddenly fall after being idle?


I work in a grocery store and sometimes after like 30 mins of being idle one of the apples or potatoes in a pile will roll down. HOW?!??

In: 1

Many things can cause this. Change of temperature will cause expansion or contraction, or it just might be slowly moving for a long time and finally reach a tipping point.

A more extreme example would be boulders that have been up a mountain for millions of years, and only now have eroded to the point where they fall.

due to the things you do not see:

a) steadily built up of pressure, up to the point were friction is overcome

b) small movements, vibrations of the surrounding (like steps, a truck moving by on the road, even a barely noticeable earthquake) you do not sense – the apple on the other hand does

c) deformations in the product itself that was compensating the pull of gravity up to the point, were it cannot deform any more but has to move

Its a little known fact that the unused lives of a cat’s nine lives just sit around waiting to be used. When bored they will knock objects of surfaces just like living cats.

The container of salt on my kitchen fan would fall down now and then, because the vibrations from the fan and a gradually sloping surface. Other, smaller containers managed to stay away from the slope, but the salt, if noone used it and put it back, eventually moved so far out that it slid off.

Slightly squishy objects such as vegetables slowly settle if something is placed on top, meaning it can be stable for some time, but slowly get less stable until it falls. Empty plastic bags also often do this if placed precariously.