do you know how many second one interval is?

Question

not sure if this help, one interval consist of 5 (spaces) dots

Answer 1

The chronometric definition of an interval is the time between two events. A question comparable to yours, is "How long is the distance?" If you want a more specific answer, ask a more specific question and put it in context.

Answer 2

Ticker tape???

5 dots implies that there is 4 intervals on a ticker tape timer.
So divide the distance by the speed between two ends and divide your result by the number of intervals there was.

(Distance divided by speed)