A domino is a rectangular block of wood or ivory with a line down the middle that divides it visually into two squares. The sides of each square are marked with an arrangement of dots or spots, called pips, similar to those on a die, although some pips may be blank. In most domino games, each end of a domino bears a number which is used to identify it, and additional tiles can be placed only on the open ends of this domino.
Dominos are used for a variety of games, including positional, draw, and block. They are typically stacked one on top of the other, and players take turns putting down dominoes edge to edge so that the adjacent faces of each domino match up, either in an identical pattern (e.g., 5 to 5) or form some specified total. The game may be won by the first player to complete this matching or by the player with the highest total at the end of a chain of dominoes.
The most common domino sets are made of polymer, a material which is inexpensive and durable, but which has a somewhat brittle quality that can result in the breaking of individual tiles in long chains. Historically, dominoes were made from a number of natural materials, including bone, silver lip oyster shell (mother of pearl), ivory, and dark hardwoods such as ebony. These sets are often more valuable than polymer ones, but they have a much higher cost and require special skills to make.
Physicist Stephen Morris explains that standing a domino upright gives it potential energy, which it stores in the force of gravity pulling down on it. When a domino falls, much of this potential energy is converted to kinetic energy, which provides the push that causes the next domino to fall over. Energy continues traveling from domino to domino until all of them have fallen.
A popular activity for both children and adults is to create domino art. This can be as simple as lining up the edges of dominoes in a straight line, creating a grid that forms pictures when they fall, or building 3D structures such as towers and pyramids. Creating domino art requires imagination and planning, but can be rewarding to see when completed.
How to Play Domino
The most popular domino games are the positional, draw, and block games. Positional games require each player to place a domino so that it touches one or more other dominoes already on the table. Depending on the rules of the game, this can be done in a number of ways, such as placing the domino so that it sits edge to edge with another domino with an equal value or so that the adjacent pairs of sides match up (e.g., 3 to 3). In this type of game, the goal is to set up a chain of dominoes so that the player can win by completing all of the required pieces before the opponent does.