We all have seen the intricate setups of thousands of dominoes that took hours to set up and 1 minute to knock down. Well, it turns out there is something actually useful to this in science besides a creative release. Teach students in a fun way about chain reactions and how distance time and average speed are interrelated by maximizing the speed of falling dominoes. Dominoes are 1.75" (43mm) x 7/8" (21mm) in size and come in the familiar black with white dot design. If nothing else they are a great way to take a break from an experiment gone bad. Sold in boxes of 55.