A domino is a rectangular tile with a line or ridge down the middle to divide it visually into two squares, one marked with an arrangement of spots, or “pips,” and the other blank or identically patterned. Each domino has a value, or rank, that is determined by the number of pips on each end. A domino with more pips on one end is generally considered heavier or higher in rank than a similar domino with fewer pips on one end. The word domino has been used in English-speaking countries since shortly after 1750, though the term may have an earlier etymological connection to a cape worn over a priest’s surplice.

In a game of domino, players take turns placing dominoes edge to edge against each other so that the adjacent faces are either identical (e.g., 5 to 5) or form some specified total. The first player to play a domino of this type takes the opening position at the table, and that player may be referred to as the setter, the downer, or the lead. The other players follow the lead by playing a tile onto the end of the opening domino, taking their position at the table according to the rules of the game.

Once all the tiles are played, the configuration of dominoes on a table is called the layout, string, or line of play. The order of play is established by drawing a domino from the stock (see “Order of Play” below). The player who draws the lowest domino seats himself to the left of the player with the highest number of pips, and so on. In some games, a player is permitted to draw additional tiles from the stock, which are known as byes. These tiles are added to the player’s hand and may be used as a means of breaking ties at the end of a hand or a game.

When creating a domino layout or line of play, students are encouraged to be as creative as possible, using straight lines, curved lines, grids that form pictures when they fall, or even 3D structures like towers and pyramids. Some students create these intricate setups for a school activity, while others practice their skills and design domino art as a hobby.

As a teacher, I often give my students the task of matching up domino pieces and connecting them end to end in a straight chain or snaked pattern. On the right side of each domino is a question, definition, or vocabulary term that they must match to the correct answer on the left. Then they record their answers on a student answer sheet.

The power of the domino effect is truly mind-blowing. In a video, University of Toronto physics professor Stephen Morris demonstrates that it only takes the tiniest little domino to trigger a sequence that ultimately results in a 13th huge domino, more than three feet tall and weighing over 100 pounds. This demonstrates the way that potential energy, stored in the mass of the domino, is converted to kinetic energy as the domino moves toward its tipping point.