When a domino falls over, it converts much of its potential energy to kinetic energy, or energy of motion. This energy travels to the next domino and gives it the push it needs to fall over. This process continues on down the line of dominoes until all have fallen.
Dominoes are a type of game piece, like playing cards or dice, that can be used in many different games. They are generally rectangular and marked on one face with a series of dots, called pips, that look very similar to the numbers on a die. The other face of the domino is blank or identically patterned.
The rules of domino vary from game to game, but the basic principles are the same for all. Each player begins the game with a hand of tiles, and each time a tile is played, it is added to the line of play. This is done by matching the pips on the open end of the tile with those on the existing dominoes on the table, creating a chain of dominoes that gradually increases in length. This is sometimes referred to as the line of play, string, or layout.
Some games require that a domino be placed on an adjacent end to an already-played tile in order to form a chain, and the number of times this is done is counted as part of the score for the game. Other games count the total number of pips on all ends of the line of play at the end of the game. Still others count only the number of pips on the ends of the first domino played in the line, known as a spinner.
After the dominoes are shuffled, each player draws a number of tiles specified by the rules for the particular game being played. This number is then added to the number of tiles that are already in his hand. If he is allowed to buy additional tiles from the stock (see Passing and Byeing below), this is done according to the rules for that game.
Most games are played in a line, and the person who makes the first play is often referred to as the setter, downer, or lead. In some games, the player holding the highest double starts the play. In other games, the winner of the previous game opens play.
If no player holds a double, or if there is a tie for the position of the heaviest domino, the players draw new hands and then begin play. The heaviest double may also be played as a single.
While most dominoes are made of ceramic, metal, or plastic, there are a wide variety of natural materials that can be used to make them. Some of the more traditional sets are made from bone, silver lip ocean pearl oyster shell (mother of pearl), ivory, or a dark wood such as ebony with contrasting black or white pips inlaid or painted on each domino.