The science of friction

 The science of friction and its surprising effect on our life

The study of friction, wear and lubrication is known as Tribology. You have all experience all three things. Remember the last time you tried to move heavy object across the floor,  and you could feel something is resisting you? That would be friction. Friction is the force that opposes motion.

Wear is loss or transfer of material. It's reason you have to replace your favorite shoes, because eventually the soles disappear. Lubricants are used to reduce friction and wear. They loosen up those stubborn rusted bolts that just otherwise will not budge.

But tribology is also defined as the science of interacting surfaces in relative motion. So, interacting surfaces in relative motion: there are lot of those in the world. As you are sitting right now, are you wiggling your foot at all or may be shifting around in your seat? Tribology is happening.

 Even the smallest shift in your seat involves two surfaces moving relative to each other. Your tribological interaction for the shift will be different than the person next to you. This is because the clothes you are wearing change the friction between you and the seat. If you are wearing silk, it's easier to squirm around in the seat than if you are wearing wool. That's because the friction is lower for silk.

If you are moving your ankle at all, did it make a popping sound? you have that, right? you get up, you move around, and some point cracks or pops. That sound can come from the fluid that lubricates your joints just moving around. You are essentially releasing gas bubbles in that fluid. 

That sound can also come from the tendons simply moving over  each other. Pretty common in the ankle, so any of my fellow wigglers out there may suddenly find themselves curious about the tribology of tendons. 

At some point of the day you must have brushed your teeth. The triblology is in action. The toothpaste and toothbrush are working to remove or wear the plaque from your teeth. You have the food, which will break and wear while you are eating, and that food is interacting with your teeth, your tongue, your saliva, your throat and all of those interaction are going to influence your experience of eating.

Tribologists are looking at lubricity, the coefficient of friction, as ways to connect  mouth feel and texture to what you are experiencing, so that if we are changing the formation of what we are eating and drinking so that sugar content or fat content are different.

You have your personal interaction with the car, the car interaction with the road and everything under the hood and in the drivetrain. Some routine maintenance is directly connected to tribology. You know how many tires are recommended for using before you replace them. You regularly check the treads on the tires.

You are actively monitoring the wear of your tires. Tribology is the study of wear and friction, and with tires, friction can be the difference between a safe arrival and a car accident. This is because the friction between your tires and the road will influence your acceleration, your deacceleration and your stopping distance.

As a driver, you instinctively already know how important friction is, because you know that when the roads are wet, they are more dangerous because they are slippery. This is because the water is reducing the friction between your tires and the road. You may recall that friction is the force that opposes motion, so water reducig that force means it's now easier for you to move, hence it's more slippery when the roads are wet.

Something else to consider is that overcoming friction takes energy, so you are loosing energy to friction. This is one way your tires can influence your fuel efficiency. In fact, did you know that about one third of fuel that you put into your internal combustion engine vehicle will be spent overcoming friction.