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  • The temperature of regular stuff is basically just a measurement of jiggliness of the atoms

  • and molecules that make that stuff up. More jiggling, higher temperature. Less jiggling,

  • lower temperature.

  • Of course, when something's at a high temperature, it feels hot, and when something's at a low

  • temperature, it feels cold. Right?

  • mmmjhyyaaanot exactly

  • If you touch a piece of metal and a book that have been sitting in your fridge, the metal

  • will feel much colder than the book - Derek of Veritasium did a great video on this, but

  • you really have to try it for yourself to believe it! The metal and the book are honestly

  • at the same temperature as measured by a thermometer, but the metal FEELS colder.

  • This isn't just a trick of the mind, though - we experience the metal as "colder" than

  • the book for a very physical reason: metal is a conductor, and paper is an insulator,

  • so the ENERGY, or jiggliness of the molecules in our hands, is absorbed more quickly by

  • the metal than by the book. Even though the book and the metal are at the same temperature,

  • the metal causes the temperature of our hands to go down faster, and thus, we experience

  • the metal as being colder - because the temperature of our hands is what we really feel.

  • It's like how, technically, a mercury thermometer really only measures its own temperature and

  • you can only indirectly measure temperatures of other things by putting them in thermal

  • contact with it.

  • Similarly, the thermoreceptive nerves in our skin can only directly measure the temperature

  • of the skin itself and not of anything else. So when we touch something, we don't feel

  • its temperature, but rather, we feel its effect on our skin: that is, how much and how quickly

  • it transfers thermal energy - that's the jiggling of molecules - to or from us.

  • The capacity to transfer thermal energy is also why a blast of steam from your stovetop

  • can feel so much hotter than a blast of hot dry air from your oven, even though the oven

  • has a higher temperature: water vapor transfers more molecular jiggling to your skin than

  • air by itself.

  • In fact, it's tempting to say that "hot" and "cold" are fundamentally different concepts

  • from "high temperature" and "low temperature", even though we usually use the words interchangeably.

  • "Hot" really means "it gives off a lot of energy" while high temperature means "it has

  • a lot of energy" - and as anyone who's tried fundraising knows, just because somebody has

  • a lot of something, doesn't necessarily mean they give a lot of it away.

The temperature of regular stuff is basically just a measurement of jiggliness of the atoms

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B1 中級

人間は本当に温度を感じることができるのか? (Can Humans Really Feel Temperature?)

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    VoiceTube に公開 2021 年 01 月 14 日
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