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Feeling the temperature of different materials

Discussion in 'General Science Discussions' started by beanz, 1 Feb 2016.

  1. beanz

    beanz Staff Member Staff Member

    One I've been wondering about recently...

    In a closed room, assuming no localised effects of sunlight/heating, over time every inanimate object in it assumes the same temperature as every other object, including the air in the room, yes?

    So why is it that touching a metal surface, it feels considerably colder to the touch than the background temperature of the room? How can that be?

    Similarly, if a car is left outside all night in freezing temperatures, why is it that frost seems to accrue on the metal surfaces differently to the glass and differently again to rubber surfaces like the tyres?
    amusicsite likes this.
  2. amusicsite

    amusicsite dn ʎɐʍ sᴉɥ┴ Staff Member

    I'm no expert but I believe metal feels colder because it's a good heat conductor. If it's colder than you and you touch it then it will try and zap the heat from your body. Therefore it's the feeling of it zapping the heat from your finger that makes it feel cold.

    Again I would think that the difference in how a material accumulates frost would be dependant on it's heat conductivity. So good insulators like tyres will not attract frost easily where as good conductors like glass and metal will.

    Or something like that. :science:
  3. Indeed ...

    It's why immersing yourself in water a few degrees above freezing would kill you very quickly, but you could stand in (still) air at the same temperature and be ok for some time.

    According to the chart on this page you would probably become unconscious in less than an hour in water at 10 degrees C, and dead within 3 hours. You would feel a bit chilled in air at that temperature but be ok. My last house was often at that temperature in winter because I only had one small working heater for the whole building.

    My new house has central heating and I keep the main rooms between 16 and 19 degrees and feel very comfortable. Water at that temperature would still kill you, it would just take longer!
    amusicsite likes this.
  4. beanz

    beanz Staff Member Staff Member

    It's a strange property of matter if you think about it. It always seems odd to me that my car can frost over while the wooden fence posts nearby don't seem to by any significant degree. Isn't physics great?! :)