Tribologists study friction: what happens when things rub together. It’s indispensable, from the wheel to the paths of stars

by Jennifer R Vail  BIO

Cinejinn/Getty Images

is a tribologist and science communicator. She is the author of Friction: A Biography (2026). She lives in the Greater Philadelphia area.

Edited byRichard Fisher

In conversations, few words catch my attention faster than ‘friction’ – and especially talk of making things frictionless. From the workplace to grocery shopping, our societies seem to be striving to remove friction from everything. The motivation appears to be that decreasing resistance makes life easier and smoother.

Having spent a career as a tribologist, studying friction, wear and lubrication scientifically, I have some opinions on this. I’ll confess that, in most of my career, I too have sought to reduce friction, developing new materials, designs or even instrumentation in order to lower friction in a jet engine or reduce emissions from your car. However, I’ve also found myself trying to figure out how to increase friction to remove plaque on teeth.

The reality is that friction, despite seeming so antagonistic, is necessary and even productive. The force that resists motion has, since humans first struck a spark from a stone, been the very thing that propels us forward. And this paradox offers a lens through which to reread humanity’s entire technological history.

In order to appreciate all that an understanding of friction has helped us to accomplish, it’s necessary to start at square one and state what friction actually is. We define friction as the force that resists motion, and that means friction is rather ubiquitous. If things are moving, whether they’re sliding around or rolling, there’s friction. Solids, liquids, gases? Doesn’t matter. If there’s movement, friction is there to resist it. Unfortunately, because friction’s job is to resist, we’ve developed an aversion to it as a nuisance. But it’s a very important force, and we’ve thrived by expanding our understanding of it. By the 1960s, after millennia of evolving with friction, we finally accepted that friction is such a critical part of our world that a scientific field of study needed to be devoted to it: tribology.

Tribologists like me study this force in all its forms. Tribology is the science of interacting surfaces in relative motion, concerned with the wear of materials, friction and lubrication. Basically, tribology is the specialisation of things rubbing against each other. You may raise an eyebrow at a field of science focused on this, but when you pause to consider how much motion is going on inside us, around us and throughout the Universe, you can appreciate that tribology is vast. More than anyone, tribologists know the problems friction can cause. But they also know the achievements that have followed as we’ve come to understand resistance better.

Although tribology as a formalised field is relatively modern, friction has long shaped humanity’s technological innovations. For example, consider its pivotal role in people’s journeys from A to B over the centuries. I’m willing to bet that whenever you need to move unwieldy furniture or carry home that giant bag of cat litter, your instinct is to find a cart to help you. Early humans had a similar thought, turning to log rollers to move heavy objects, and coming up with one of our greatest inventions: the wheel. Rolling makes it easier to move objects because it reduces friction between the object and surface you’re moving it against. There are far fewer surface interactions in the process of rolling versus sliding. Plenty can be said about the wheel, including the fact that even in 2026 we can’t seem to agree on the origin of its discovery, but there is zero doubt that it’s a brilliant innovation for dealing with friction. But wheels also need friction: when we exert a force to move a wheel forward, the force between the ground and the wheel – static friction – keeps it from spinning freely, which would result in us going nowhere. Once forward motion begins, the resistance to motion becomes dynamic friction, which is just as important. If you’ve driven on ice, you know the danger of too little friction.

However, if people hadn’t continued improving on these basic principles, even the wheel would be rather inefficient due to friction.

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