# How Do Dominoes Work?

Dominoes are the building blocks of many games that involve setting up and knocking over lines of tiles. But these small, rectangular pieces of wood, often referred to as bones, cards, men, or pieces, can also be used for art projects, or even to build 3D structures like towers and pyramids.

Lily Hevesh began playing with dominoes when she was 9 years old, and by age 10, her collection had grown significantly. She started posting videos of her creations on YouTube, and now she has more than 2 million subscribers. Her projects include straight and curved lines, grids that form pictures when they fall, and intricate designs built from thousands of dominoes.

But Hevesh doesn’t just set her dominoes up and let them tumble—she relies on science to create the amazing displays she’s known for. One physical phenomenon in particular is essential for her projects: gravity. This force pulls a knocked-over domino toward Earth, which in turn sends it crashing into the next tile and setting off a chain reaction.

When a domino is set up, the ends that face the ground are marked with an arrangement of spots or pips, which determine its value and indicate how it should be placed in the layout. Each domino is typically twice as long as it is wide, which allows players to re-stack them after use. A domino that has a number on both ends is called a double, while the other end can either be blank or have another number if the set contains more than one type of tile.

For most domino games, a player must place a domino so that it touches an edge of the previous tile and extends past the end of the line of dominoes. Then, in a turn, the player must play another domino over that one, positioning it so that its end touches an open end of the previous tile and extends past that edge. The players continue this process until the entire domino chain is complete, and the last domino remains unbroken, touching the ground.

To avoid cheating, the tiles in a domino set are mixed up before each round of play. Each player draws a hand of tiles, which are then laid out in front of him or her. The tiles must remain in this position until the player is ready to place his or her hand, at which time the player will reposition them in the desired position.

As a result, the pieces will have varying degrees of friction with each other and the surface on which they are resting. The movement of the dominoes causes a conversion of some energy into heat and sound, but most of the energy is transferred by the gravitational force acting on them. The first domino that falls takes a little bit of the potential energy from the other dominoes to push over them, but once it begins falling, the remaining energy becomes available for other actions.