About the ticker-tape timer

A ticker tape timer is a device that works by making marks on ticker tape with inked carbon paper or an electrical spark as the paper is pulled through the ticker tape timer. The timer makes these marks at regular intervals. The space between intervals depends on how fast the paper is pulled through the timer. The faster the paper is pulled the longer the distance between the intervals. Usually the intervals are a fraction of a second but can be much longer. A stopwatch is used to measure the time elapsed so that calculations can be made from the results

Electromagnet act the same way as a relay in electrical circuit.

The most important points to note in a ticker timer experiment are:
1. the time intervals between dots are the same;
2. the separations between successive dots give the distances travelled.