Passage
In a cool room, a metal railing and a wooden railing stand side by side, and the two have sat in the room for hours. To the touch the metal feels much colder than the wood. Two students agreed that the metal feels colder, but they disagreed about why.
Student 1: The two railings are at the same temperature; the metal only feels colder because it carries heat away from your hand much faster than the wood does. What your hand senses is how quickly heat leaves it, not the object's temperature. On this view, a thermometer touched to each railing should read the same, the chilly feeling should ease as your hand warms the spot it touches, and any good heat conductor should feel colder than a poor conductor at the same temperature.
Student 2: The metal really is colder than the wood. Metal holds the cold and settles to a lower temperature than nearby wood, even when both sit in the same room for hours. On this view, a sensitive thermometer touched to each railing should read the metal a few degrees lower than the wood, and the metal feels colder for the simple reason that it truly is colder.
