Dominoes are rectangular blocks of wood or cardboard, normally twice as long as wide. They are marked with an arrangement of spots (or “pips”) on one side and blank or identically patterned on the other. The number of pips distinguishes each domino from another, and determines its value in a game. Dominoes also feature a line in the middle that divides it visually into two squares, called ends. Each end may have a different value. The number of pips on either end may be equal or differing, depending on the particular game being played.
Some people use dominoes as toys, stacking them on their end in long lines and knocking them over to cause a chain reaction. This led to the popular term, “the domino effect.” Some children even line them up in elaborate designs and then knock them over. Regardless of how they are used, dominoes are an excellent example of simple, yet elegant physics.
The science of a domino chain relies on an ordinary physical phenomenon—gravity. When a domino is standing upright, it has potential energy—energy stored based on its position. When a domino is knocked over, much of this potential energy is converted to kinetic energy—energy in motion—which pushes the next domino toward the ground and causes it to topple. The energy continues moving from domino to domino in a chain reaction until all of the dominoes have fallen.
To play a domino game, players draw their tiles and place them on the table, positioning them so that each domino touches one of the ends of the previous tile or set of tiles. Then the first player, determined by drawing lots or by who holds the heaviest hand, plays a tile on the end of the line. Each subsequent player places a domino on the line so that it matches the previous tile’s end and extends its shape along the length of the table.
As the domino chain grows, each player tries to make the largest possible combination of numbers in the pattern displayed on his or her tiles. The winner is the player who has a combination that exceeds any other combination of numbers on the table.
While there are many different games that can be played with a domino set, most fall into two categories: blocking and scoring games. Blocking games involve creating a sequence of dominoes that is impossible to break, while scoring games require the creation of a series of chains and other structures with specific values.
While the science behind domino is fascinating, some of the most interesting information about this simple toy comes from the creative minds who use it to create stunning displays. For example, domino artist Hevesh, who has worked on projects involving hundreds of thousands of dominoes, says that gravity is the most important force at work in her mind-blowing creations. She explains that when she builds a massive domino structure, she begins by considering the theme or purpose of the installation, and then brainstorms images and words that relate to this theme. She then follows a version of the engineering-design process to plan out the pieces she needs and how they will fit together.