A domino is a small, rectangular block with identifying markings on one side and a blank or identically patterned opposite side. The identifying marks, called pips, are arranged like those on dice. Most dominoes have the same pattern on both sides, but some have different patterns or no pattern at all. A domino may be made of any material, but wood is the most common.
Dominoes are used to play games in which players try to build a chain of tiles across the floor or table. Each tile has a number of points, called pips, that represent numbers from one to six. A domino with no pips is called a zero. Each player draws his or her own set of dominoes, but the first tile to be played is usually a double-six (or another number that can easily be matched). The players then draw a line of tiles in front of them, and each places a domino in the line, touching its matching end.
The physics of the chain reaction is a bit more complex than that, but the general idea is the same: When a domino is standing upright, it has potential energy, or stored energy based on its position. When it is tipped over, much of this potential energy is converted to kinetic energy, or the energy of motion, and this propels the next domino in the line down its path. The process continues until all the dominoes have fallen.
Many types of domino games exist, including block, scoring, and spotting games. Traditionally, the game of dominoes is played by two or more people and is scored in accordance with rules specific to each game. The winner is the person who plays all of his or her dominoes before all other players have had an opportunity to play their own.
Besides being fun to play, dominoes are attractive objects that can be arranged into shapes and designs. Stacking them on end in long lines, for example, can create intricate works of art. In addition, dominoes are useful educational tools for learning about the laws of gravity and simple mechanics.
Dominoes can also be used to teach about the concept of “domino effect,” which is the phenomenon in which a single event causes a series of events with greater–and sometimes catastrophic–consequences. When used in this context, dominoes are often referred to as “good dominoes,” meaning tasks that contribute to the completion of a larger goal.
Although there are several ways to play a domino game, most of them involve matching one domino with its adjacent neighbor, either by counting the total of all of the dots on the exposed ends or by comparing the values of any numbers on both sides. A double-six is played to any other domino touching it at both of its ends, regardless of the direction in which it is placed; thus, the domino chain develops a snake-like shape on the table as players alternately place tiles.