if I am sitting at the hydrogen nucleus and need to explain behavior of 1s electron over time to a 15 year old child in layman language. I will ask child to note the position of hydrogen after every blink of an eye. If your eye blinks very slowly than probably you will find electron at same position after each blink. However if your eye blinks very fast, faster than velocity of electron, then you will be able to observe different position of electron at different blink (a time average position)