Why are certain materials colder than others? (i.e. metal compared to wood)
In: Physics
There is a heat flux from yiur hand to the touched material. This is basically defined by. heat conductivity and heat capacity and the temperature difference.
Heat capacity guves you an idea how mwich energy is needed to heat an meterial up.
The more energy you need to heat the material up (the higher the heat capacity) the colder your hand get.
Heat conductivity is about how far energy is transporter through the Material. Material with high cinductivities get warmer in a distance. Therefore more energy is needed since you have to heat more material.
If you touch foam. Low heat conductovity (the energy stays close to your hands) and low heat capacity (you dont need much energy to heat it up)
Therefore your hand stays warm.
If you touch a metal wit high conductivity and capacity you will need more energy ti heat it up, therefore your hand is cooled much more down.
You don’t feel “heat” or “cold” in absolute terms. What you feel is the transfer of energy to or from your body. The faster energy leaves your body, the colder it feels. The faster energy enters your body, the hotter it feels.
Metal transfers heat more readily than wood (both in and out). So a cold metal will pull more heat from your body, and thus feel colder, than wood at the same temperature. Likewise, hot metal will push heat into your body more than wood of the same temperature and feel hotter, as anyone who’s played on a playground on a hot day can tell you.
Wood is a poor heat conductor, but good insulator, so when you touch it, it doesn’t absorb the heat from your hand quick, so it feels warm
Metals are good heat conductors, so when you touch them they absorb heat from your hand much faster so they feel cold to the touch.
Simple explanation: At room temp, everything is obviously the same temperature, whether it’s metal or wood.
But metal conducts heat better. That means metal will cool down your hands from 95F down to 72F faster. That faster heat transfer is what you perceive as cool.
It’s also the reason why insulation like styrofoam never feels particularly hot or cold.
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