In a thermodynamic class I took in 1989, the professor was talking about the transfer of heat and someone asked this question. The prof. didn’t attempt to explain it because it was off topic from the lecture, but he did say the answer had a more complex biological reason, and not that the floor was actually colder.
In: Biology
Conduction, your foot is warmer than the environment and the tile conducts heat away from your foot, leaving your foot cooler than it was, so the tile feels cold.
The tile “feels” cold because the tile is good at conducting heat OUT of your body and into the tile.
The tile is not actually colder than everything else in the room it’s just better at drawing heat out of your body which makes you feel colder.
Thermal conductivity, and thermal mass. How quickly does the point of contact spread heat to the rest of the mass, and how much energy does the rest of that mass take to reach equilibrium with your body temperature?
Tile at a given temperature will transfer heat faster than carpet or wood. This works in both directions, if the tile is warmer than body temperature it will feel hotter than wood or carpet the same temperature.
Not everything is in equilibrium! You are hotter than the room. The time carries away your heat faster
The tile and the air in room are same temperature (say, 22°C). Your body is warmer than both (cca 36°C). Some materials are better at leaching warmth from you than others. Air in particular is shit (an insulant), so most room-temperature objects feel a bit cool to touch, compared to touching nothing/air. Metals in particular are very good at this (i.e. they “conduct heat well”)
Because your foot is warmer than the floor. You are producing heat through chemical reactions in your body and the floor is not producing heat
Imagine two different things are traveling the same speed. Let’s say a baseball and a car. Both traveling 60 mph.
If both hit you, one is going to hurt a lot more, even though they were traveling the same speed. Some materials have more “weight” … aka Thermal Mass.
Air has terrible thermal properties. It’s why you can reach into an oven, and the 350F air doesn’t bother you very much. But if you touch a 350F metal baking sheet you get burned instantly.
A key point is that your sense of ‘hot’ and ‘cold’ is not measure of temperature. It is a measure of is your body gaining or losing heat, and how much, relative to what would be ideal for you body at that moment.
How cold something feels has very little to do with temperature and more to do with how well that thing conducts heat.
The feeling of cold comes from how quickly an object is able to absorb heat from your hand. At 70* room temperature, a pillow, for example, is a poor conductor of heat, so it will not feel cold when you grab it. A block of aluminum is a very good conductor of heat, when you grab that, it quickly absorbs the heat from your hand and “feels” cold even though it’s the same temperature as the pillow.
Likewise, walking barefoot on carpet (poor heat conductor) feels fine, but walking across ceramic tile (much better heat conductor) feels quite cool.
As a human you have a specific body temperature that is generally higher than room temperature. As such if you touch a thermally conductive object it will feel cold to you because you’re warmer than it and it’s “sucking” in your heat and dissipates it. Now if it was a very warm room, close to human body temperature, things would stop feeling cold to the touch, even the fairly conductive ones. Of course it would also be quite an unpleasant room to be in.
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