I know that i could buy a stop watch that had milliseconds and i know that you could divied a seconed by 1000 but i really want to know how you can tell how long a milliseconed is not in reference to smaller units of time but physicly

A fast runner can reach about 10 metres per second so a millisecond is roughly the time it would take them to cover the length of the last word here.

I know that i could buy a stop watch that had milliseconds and i know that you could divied a seconed by 1000 but i really want to know how you can tell how long a milliseconed is not in reference to smaller units of time but physicly

 

There is a standard definition of the second (in terms of physical effects). The millisecond is just one thousandth of that.

I know a falling object falls at 9.8m/s for the first second, So you could drop an object from this height against a measured background, Perhaps video it or have a camera that takes so many shots per second, you could work out and see how far the object falls in a millisecond,

I will leave that for someone good at maths