# The Physics of Domino

Domino is a game played with small rectangular blocks, called dominoes, each bearing one to six pips (or dots): 28 such pieces make up a complete set. Players score points by placing a domino down on a line or a curve, or by knocking over a chain of dominoes already in place. The simple act of laying down a single domino can start a sequence that leads to elaborate designs and even chain reactions that create fireballs of dominos that topple over in a wavelike fashion.

The physics of this phenomenon is not complicated, says Stephen Morris, a University of Toronto physicist: When you pick up a domino and stand it upright against the pull of gravity, it stores potential energy, which is converted to kinetic energy when the domino falls over. This chain reaction, like the firing of a neuron, moves at a constant speed and in one direction only.

Lily Hevesh, 20, grew up playing domino with her grandparents’ classic 28-pack. She loved to watch the dominoes fall in a straight or curved line, one after the other. Today she is a professional domino artist who has created setups for movies, TV shows, and events–including the album launch for pop star Katy Perry.

When she’s not making these massive creations, Hevesh is posting videos of her domino projects on YouTube. Her channel has more than 2 million subscribers. “Domino is a symbol of perseverance and overcoming obstacles,” she says. “It can be hard to get started when you’re new to something, but once you get the hang of it, you can see your progress.”

Although there are many different games that can be played with dominoes, some have similar or identical rules. When playing a game with two or more players, a player draws a number of dominoes that correspond to the rules of the game being played and then places them in front of him in such a way that the other players can’t see the pips on the tiles. The player who holds the heaviest double starts play.

If a player cannot play any of the dominoes in his hand, he passes and does not draw another tile from the stock. Some games allow a player to buy tiles from the stock, and in this case, the number of pips on the purchased tiles is added to the winner’s total score.

Most of the games described here are played with a set of tiles that are shuffled and then drawn in order by each player according to the rules of the game being played. However, there are also games that are played without the use of a stock and can be played by a single player. These games are listed under the heading of Line of Play.