American 3B Scientific U49524 Acceleration Spark Timer;

Great for measuring acceleration of falling weight, and it exerts less resistance than a ticker tape timer This apparatus is used for determining the rate of acceleration in a falling weight, calculating the speed of a moving cart or studying the forces of friction. A paper strip is pulled through the timer while a spark at a very precise interval is created which burns tiny dots into the paper strip as it passes. The faster the strip passes through the sparks, the larger the distance between dots. It is then easy for the student to calculate the rate of speed for acceleration. As an added benefit, everything on the spark timer is enclosed for safety. Instructions included. (6-1/4" x 2-3/4" x 4-1/4"; 1.75lbs).  110 V plug comes built in.