Why does a smooth surface feel colder than a rough surface when the material is the same?

I have 2 of those plastic chairs on my porch, one is new and smooth, the other is older and the surface is rougher from weathering. Why does the new one feel so much colder against the back of my legs?



The chairs have a lower temperature than your body. The one with the smooth surface has more contact with your body than the one with the rough surface, so more heat transfers from you to it. (feels colder). If the chairs were in the sun all day, and hotter than your body, then the smooth one would feel hotter.




Fricton applys more resistance against the force of your leg.To move your leg along the rough chair takes more energy then the smooth chair expelling thermal energy as a byproduct.




its because more of the surface is touching your skin. The more area of contact, the faster the colder material draws heat out of the warmer




The smooth one contacts the skin with greater surface area and, therefore, conducts heat from your skin quicker. The rough one only contacts at the top of the bumps.




because there is more friction between the rough surface than the smooth surface. So therefore there is more heat. :)




yes