If more surface area = more friction, than why do textured objects that have less surface area “cling” better?
In: Physics
Textures increase surface area. Put simply, a flat surface has a very basic surface area. Adding ridges increases the surface area, because you have additional area in the upward and downward slope.
It’s one of the reasons things like heat sinks tend to have a bunch of right angled raised areas, so there’s more surface area to disappate heat.
They don’t, they have more traction, which is different than friction.
Friction doesn’t account for things bending or breaking when they come into contact, or the liquids or gases that might be trapped between two objects. A smooth tire on a wet road will have poor traction because it will ride on top of a layer of water. A tire with groves lets the water escape and maintains contact with the road.
You are right that more surface area tends to mean more friction.
Textured surfaces have more surface area than flatter ones. Imagine a straight line from point A to point B versus a “textured” line that zig zags and curves around on its way from A to B?
Which line is longer? The “textured” line is. If you bring this example into the third dimension, you can see why a textured surface has more surface area than a flatter one
Everyone here saying friction is related to surface area is flat out wrong. Unless the surface area is insanely small then it may matter because the mall object can begin to dig into the larger one. Friction is related to the force between two objects and something called the coefficient of friction (K). K depends on the material of both surfaces. Your statement that textured surfaces hold more friction is generally true but not always. One of the highest know K values actually occurs between one smooth glass surface and another believe it or not.
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