how do things suddenly fall after being idle?

Question

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

Answer 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.