Wednesday, September 28, 2022
HomePhysicsFriction Is Key in Domino Physics

Friction Is Key in Domino Physics

• Physics 15, 83

A serious marketing campaign of domino-toppling simulations yields new insights into the results of friction.

Falling over themselves. New simulations reveal the position of friction within the seemingly easy mechanics of domino toppling. (See movies beneath.)

Regardless of the obvious simplicity of toppling dominoes, physicists nonetheless don’t have an entire mannequin of the phenomenon. However new numerical simulations get a step nearer by untangling the affect of two sorts of friction—one between neighboring dominoes and the opposite between every domino and the floor beneath it [1]. The researchers discovered that, in some circumstances, these two friction coefficients play competing roles in figuring out the pace of the domino cascade. In addition they discovered that one of many coefficients behaves much like friction in granular methods similar to piles of sand or pharmaceutical capsules, suggesting that the domino simulations could present insights into different conditions the place friction is vital.

A YouTube video by engineer Destin Sandlin (on his channel Smarter Each Day) impressed David Cantor of Montreal Polytechnic and Kajetan Wojtacki of the Institute of Basic Technological Analysis of the Polish Academy of Sciences in Warsaw to review dominoes. Sandlin recorded a collection of domino toppling experiments with a high-speed digital camera and shortly found simply how complicated the issue is. He decided that the wave of falling dominoes strikes barely quicker on felt than on a slippery hardwood ground. He additionally noticed shocking anomalies, similar to circumstances the place the practice of toppling dominoes would abruptly cease.

Sandlin noticed {that a} slippery floor could cause a domino to slip backward whereas falling ahead and thus hit the subsequent domino considerably decrease down when put next with dominoes on high-friction felt. However experimental limitations prevented him from totally explaining the results of friction on the wave pace. Researchers have beforehand carried out experiments and simulations and developed theories for domino toppling, however nobody has systematically studied how domino-surface friction, domino-domino friction, and domino spacing have an effect on the wave pace. Cantor and Wojtacki carried out simulations that may totally management these parameters in hopes of higher explaining observations.

D. Sandlin/Smarter Each Day

On a slippery floor, dominoes slide again as they fall ahead. (Clip from Sandlin’s first dominoes video.)

D. Sandlin/Smarter Each Day

On a floor with friction, there may be a lot much less backsliding. (Clip from Sandlin’s first dominoes video.)

From their complete marketing campaign of 1210 simulations that included 200 dominoes in every, Cantor and Wojtacki discovered that, when the spacing is half of the domino thickness, domino-surface friction and domino-domino friction play competing roles: Growing the friction between dominoes causes the wave entrance to decelerate as a result of friction absorbs some power from the wave of movement. Growing friction with the floor beneath accelerates the wave as a result of it reduces domino backsliding, permitting each to strike its neighbor larger up, the place the impression is more practical, the researchers consider.

Nonetheless, when the dominoes had been extra extensively spaced—the staff noticed spacings as much as 5 occasions the domino thickness—the floor friction had little impact on the wave pace. Cantor and Wojtacki assume that at larger spacings, the dominoes fall farther and therefore purchase extra kinetic power earlier than hitting their neighbors. When impacted extra forcefully, it seems {that a} domino is much less prone to backslide, whatever the floor friction.

Cantor and Wojtacki additionally discovered that for spacings wider than 3 occasions the domino thickness, the wave was unstable and will spontaneously cease if the floor was comparatively slippery and the domino-domino friction was excessive. On this case, the backsliding may trigger the wave to stop due to the broad spacing—a domino may slide again to this point that it may topple however by no means attain its neighbor.

The pair additionally noticed that in the event that they elevated the domino-domino coefficient of friction past 0.4, the wave entrance pace didn’t change a lot. Cantor and Wojtacki assume that the upper the friction, the much less the dominoes slide in opposition to each other, so, finally, the quantity of friction doesn’t matter. The researchers write {that a} related “saturation” impact at a worth of about 0.4 has been seen in research of the impact of friction on the steepness of the edges of a secure pile of sand or different granular materials. So that they speculate {that a} common phenomenon could also be concerned.

Caishan Liu of Peking College says that domino-like habits is ubiquitous and is seen in phenomena starting from nanofriction and molecular collisions to earthquakes and financial actions. “Characterizing the connection between macroscopic movement and microscopic mechanisms of such methods has been one of many elementary scientific points,” he says.

Liu thinks Cantor and Wojtacki’s work is “vital for understanding the connection between the worldwide habits of the domino system and the bodily parameters,” however he says the issue is way from solved. “There may be nonetheless a variety of work to be finished to disclose the bodily mechanisms.”

Correction (21 June 2022): This story has been up to date with the right identify of Wojtacki’s establishment.

–Katie McCormick

Katie McCormick is a science author based mostly in Seattle, Washington.


  1. D. Cantor and Ok. Wojtacki, “Results of friction and spacing on the collaborative habits of domino toppling,” Phys. Rev. Utilized 17, 064021 (2022).

Extra Info

Topic Areas

Associated Articles

Motion Synchronization Goes Long Distance
Explaining the Mechanics of a Bird’s Nest
Airborne Spiders Drift on Multiple Silk Threads

Extra Articles



Please enter your comment!
Please enter your name here

Most Popular

Recent Comments