How to Increase Friction
Create a “rougher” or more adhesive point of contact., Press the two surfaces together harder., Stop any relative motion., Remove lubrication between the two surfaces., Remove wheels or bearings to create sliding friction., Increase the fluid...
Step-by-Step Guide
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Step 1: Create a “rougher” or more adhesive point of contact.
When two materials slide or rub against each other, three things can happen: small nooks, crannies, and irregularities on the surfaces can catch on each other; one or both surfaces can deform in response to the motion; and, finally, the atoms within each surface can interact with each other.For practical purposes, all three of these effects do the same thing: generate friction.
Picking surfaces that are abrasive (like sandpaper), deform when pressed (like rubber), or have adhesive interactions with other surfaces (like tacky glue, etc.) is a straightforward way to increase friction.
Engineering textbooks and similar resources can be great tools when picking which materials to use to generate high friction.
Most standard building materials have known "friction coefficients" — that is, measures of how much friction they generate with other surfaces.
Sliding friction coefficients for just a few common materials are listed below (higher coefficients indicate greater friction):
Aluminum on aluminum:
0.34 Wood on wood:
0.129 Dry concrete on rubber:
0.6-0.85 Wet concrete on rubber:
0.45-0.75 Ice on ice:
0.01 -
Step 2: Press the two surfaces together harder.
One fundamental principle of basic physics is that the friction an object experiences is proportional to its normal force (for our purposes, this is basically the force with which it presses into the object it's sliding against).This means that the friction between two surfaces can be increased if the surfaces are pressed into each other with greater force.
If you've ever used a set of disc brakes (for instance, on a car or bike) you've observed this principle in action.
In this case, pressing the brakes pushes a set of friction-generating pads into metal discs attached to the wheels.
The harder the brakes are pushed, the harder the pads get pressed into the discs and the more friction is generated.
This can stop the vehicle quickly, but can also release lots of heat, which is why a set of brakes is usually quite hot after heavy braking., That is, if one surface is in motion with respect to another, stop it.
Up until now, we've focused on kinetic (or "sliding") friction — the friction that occurs between two objects or surfaces as they rub against each other.
In fact, this friction is different from static friction — the friction that occurs when one object starts to move against another.
Essentially, the friction between two objects is greatest right when they start moving against each other.
Once they're already in motion, friction decreases.
This is one of the reasons why it's harder to start pushing a heavy object than it is to keep moving it.Try this simple experiment to observe the difference between static and kinetic friction: place a chair or another piece of furniture on a smooth floor in your house (not rug or carpet).
Make sure the furniture doesn't have protective "foot pads" or any other sort of material on the bottom that might make it easy to slide across the floor.
Try to push the furniture just hard enough so that it starts moving.
You should notice that as soon as the furniture starts moving, it immediately becomes slightly easier to push.
This is because the kinetic friction between the furniture and the floor is less than the static friction. , Lubricants like oil, grease, petroleum jelly, and so on can greatly reduce the friction between two objects or surfaces.
This is because the friction between two solids is generally much higher than the friction between those solids and the liquid between them.
To increase friction, try removing any lubricants from the equation, using only "dry"
un-lubricated parts to generate friction.
To see the friction-reducing potential of lubricants, try this simple experiment:
Rub your hands together as if they're cold and you want to warm them up.
You should immediately notice them heat up from the friction.
Next, put a fair amount of lotion in your palms and try the same thing.
Not only should it be easier to rub your hands against each other quickly, but you should also notice much less heat. , Wheels, bearings, and other "rolling" objects experience a special kind of friction called rolling friction.
This friction is almost always much less than the friction generated by simply sliding an equivalent object along the ground. — This is why these objects tend to roll, rather than slide along the ground.
To increase the friction in a mechanical system, try removing wheels, bearings, and so on so that parts rub against each other rather than roll against each other.For instance, consider the difference between pulling a heavy weight along the ground in a wagon versus pulling a similar weight in a sled.
A wagon has wheels, so it's easier to pull than a sled, which drags against the ground, generating lots of sliding friction as it goes. , Solid objects aren't the only things that can generate friction.
Fluids (liquids and gases like water and air, respectively) can also generate friction.
The amount of friction a fluid generates as it passes against a solid depends on several factors.
One of the easiest of these to control is the fluid viscosity — that is, what's commonly called its "thickness".
Generally, highly viscous fluids (ones that are "thick"
"gooey"
etc.) generate more friction than fluids that are less viscous (ones that are "smooth" and "liquid").
For instance, consider the difference in effort you might experience when blowing water through a straw versus blowing honey through a straw.
Water, which isn't very viscous, is very easy to suck into and blow out of a straw.
Honey, on the other hand, is quite a bit more difficult to move through a straw.
This is because honey's high viscosity generates lots of resistive friction as it's forced through a narrow tube like a straw. -
Step 3: Stop any relative motion.
-
Step 4: Remove lubrication between the two surfaces.
-
Step 5: Remove wheels or bearings to create sliding friction.
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Step 6: Increase the fluid viscosity.
Detailed Guide
When two materials slide or rub against each other, three things can happen: small nooks, crannies, and irregularities on the surfaces can catch on each other; one or both surfaces can deform in response to the motion; and, finally, the atoms within each surface can interact with each other.For practical purposes, all three of these effects do the same thing: generate friction.
Picking surfaces that are abrasive (like sandpaper), deform when pressed (like rubber), or have adhesive interactions with other surfaces (like tacky glue, etc.) is a straightforward way to increase friction.
Engineering textbooks and similar resources can be great tools when picking which materials to use to generate high friction.
Most standard building materials have known "friction coefficients" — that is, measures of how much friction they generate with other surfaces.
Sliding friction coefficients for just a few common materials are listed below (higher coefficients indicate greater friction):
Aluminum on aluminum:
0.34 Wood on wood:
0.129 Dry concrete on rubber:
0.6-0.85 Wet concrete on rubber:
0.45-0.75 Ice on ice:
0.01
One fundamental principle of basic physics is that the friction an object experiences is proportional to its normal force (for our purposes, this is basically the force with which it presses into the object it's sliding against).This means that the friction between two surfaces can be increased if the surfaces are pressed into each other with greater force.
If you've ever used a set of disc brakes (for instance, on a car or bike) you've observed this principle in action.
In this case, pressing the brakes pushes a set of friction-generating pads into metal discs attached to the wheels.
The harder the brakes are pushed, the harder the pads get pressed into the discs and the more friction is generated.
This can stop the vehicle quickly, but can also release lots of heat, which is why a set of brakes is usually quite hot after heavy braking., That is, if one surface is in motion with respect to another, stop it.
Up until now, we've focused on kinetic (or "sliding") friction — the friction that occurs between two objects or surfaces as they rub against each other.
In fact, this friction is different from static friction — the friction that occurs when one object starts to move against another.
Essentially, the friction between two objects is greatest right when they start moving against each other.
Once they're already in motion, friction decreases.
This is one of the reasons why it's harder to start pushing a heavy object than it is to keep moving it.Try this simple experiment to observe the difference between static and kinetic friction: place a chair or another piece of furniture on a smooth floor in your house (not rug or carpet).
Make sure the furniture doesn't have protective "foot pads" or any other sort of material on the bottom that might make it easy to slide across the floor.
Try to push the furniture just hard enough so that it starts moving.
You should notice that as soon as the furniture starts moving, it immediately becomes slightly easier to push.
This is because the kinetic friction between the furniture and the floor is less than the static friction. , Lubricants like oil, grease, petroleum jelly, and so on can greatly reduce the friction between two objects or surfaces.
This is because the friction between two solids is generally much higher than the friction between those solids and the liquid between them.
To increase friction, try removing any lubricants from the equation, using only "dry"
un-lubricated parts to generate friction.
To see the friction-reducing potential of lubricants, try this simple experiment:
Rub your hands together as if they're cold and you want to warm them up.
You should immediately notice them heat up from the friction.
Next, put a fair amount of lotion in your palms and try the same thing.
Not only should it be easier to rub your hands against each other quickly, but you should also notice much less heat. , Wheels, bearings, and other "rolling" objects experience a special kind of friction called rolling friction.
This friction is almost always much less than the friction generated by simply sliding an equivalent object along the ground. — This is why these objects tend to roll, rather than slide along the ground.
To increase the friction in a mechanical system, try removing wheels, bearings, and so on so that parts rub against each other rather than roll against each other.For instance, consider the difference between pulling a heavy weight along the ground in a wagon versus pulling a similar weight in a sled.
A wagon has wheels, so it's easier to pull than a sled, which drags against the ground, generating lots of sliding friction as it goes. , Solid objects aren't the only things that can generate friction.
Fluids (liquids and gases like water and air, respectively) can also generate friction.
The amount of friction a fluid generates as it passes against a solid depends on several factors.
One of the easiest of these to control is the fluid viscosity — that is, what's commonly called its "thickness".
Generally, highly viscous fluids (ones that are "thick"
"gooey"
etc.) generate more friction than fluids that are less viscous (ones that are "smooth" and "liquid").
For instance, consider the difference in effort you might experience when blowing water through a straw versus blowing honey through a straw.
Water, which isn't very viscous, is very easy to suck into and blow out of a straw.
Honey, on the other hand, is quite a bit more difficult to move through a straw.
This is because honey's high viscosity generates lots of resistive friction as it's forced through a narrow tube like a straw.
About the Author
Susan Flores
Enthusiastic about teaching organization techniques through clear, step-by-step guides.
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