A domino, or set of dominoes, is a small rectangular wooden block the face of which has been divided into two parts. The lower part bears from one to six pips or dots, resembling those on dice. A complete set of dominoes contains 28 such pieces. A game played with such blocks, called dominoes (or dom*i*nos, plural dom*i*nos), is usually a blocking or scoring game involving matching the ends of pieces and laying them down in lines or angular patterns. A number of other games, many of which are variations on card games, can be played with a domino set, as well. Some of these were once popular in areas that imposed religious proscriptions on playing cards, but most are variants of blocking or scoring games.
Dominoes can also be used to illustrate basic concepts in science and mathematics. For example, a student may use dominoes to demonstrate the principle of conservation of energy by showing that a larger mass exerts a greater force on its neighbor. A person can also use a domino set to study the principles of gravity, and to investigate the effect of varying the height of a stack of dominoes on the force exerted by each domino in the pile.
When a domino falls, it transmits its potential energy to the next domino, which becomes kinetically active. This energy is transferred from domino to domino, and so on, until the last domino has been knocked over. The total amount of energy transmitted is called the chain reaction, and it is an important property of the domino game that allows for such elaborate creations.
Hevesh, who has built up a huge following on her YouTube channel, has created mind-blowing domino installations for movies, TV shows and events. Some of her creations have involved hundreds of thousands of dominoes and have taken several nail-biting minutes to fall. She explains that when creating a domino setup, she follows a version of the engineering-design process.
The word domino derives from a Latin adjective, meaning “slender.” It was adopted in English around 1750, probably along with the verb, which had earlier denoted a long hooded cloak worn together with a mask at carnival season and masquerades. It also referred to a cape worn by priests over their surplices. The ebony blacks and ivory faces of domino pieces are said to have reminded people of the hood and mask.
While the most popular dominoes are made of polymer, other materials have been used. Traditional European-style sets are made of bone, silver lip ocean pearl oyster shell (mother of pearl, or MOP), or a dark hardwood such as ebony, with contrasting pips inlaid or painted. More recently, sets have been manufactured from natural materials such as stone; metals such as brass or pewter; ceramic clay; and frosted glass. They are more expensive than polymer dominoes, but are characterized by a richer look and a firmer feel. They are also more difficult to damage or scratch, and they will not become discolored by liquids or oils.