章节大纲

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  • 热热热

    A chef carefully removes a baking pan of corn bread from a hot oven using mitts.

    Watch out! This chef is taking corn bread out of a hot oven using an oven mitt. Touching the baking pan with bare hands could cause a painful burn. However, the air inside the oven doesn’t hurt. How can this be? Explore the Hot Oven simulation below to find out:
    ::当心!这个厨师正在用烤箱手套从热烤箱中取出玉米面包。 光手摸烤锅可能会造成痛苦的烧伤。 但是,烤箱中的空气并不痛。 这怎么可能。 试探下面的热奥文模拟以了解:

    What Is Heat?
    ::什么是热?

    Heat is the transfer of between substances. Thermal energy is the of moving particles of matter, measured by their . Thermal energy always moves from warmer to cooler substances. You can see this in the Figure . Faster-moving particles of the warmer substance bump into and transfer some of their to slower-moving particles of the cooler substance. Thermal energy is transferred in this way until both substances have the same thermal energy and temperature. 
    ::热能是物质之间的热转移。热能是物质移动颗粒,以其量度。热能总是从更暖的物质向更冷的物质移动。您可以从图中看到这一点。热能的移动速度更快的粒子会撞上一些物质,并将其中一些物质转移到更冷物质的移动速度较慢的颗粒。热能以这种方式转移,直到两种物质都具有同样的热能和温度。

    Particles of two substances A and B exchanging thermal energy when in contact.

    Q: How is thermal energy transferred in an oven?
    ::问题:热能如何在烤箱中转移?

    A: Thermal energy of the hot oven is transferred to the cooler food, raising its temperature.
    ::A:热炉的热能被转移到更冷却的食物,提高温度。

    Cooling Down by Heating Up
    ::通过加热降温降温

    How do you cool down a glass of room-temperature cola? You probably add ice cubes to it, as in the Figure . You might think that the ice cools down the cola, but in fact, it works the other way around. The warm cola heats up the ice. Thermal energy from the warm cola is transferred to the much colder ice, causing it to melt. The cola loses thermal energy in the process, so its temperature falls.
    ::如何冷却一杯室温可乐?你可能会在其中添加冰块,如图所示。你可能会认为冰会冷却可乐,但实际上,它会起到相反的作用。热可乐会将冰加热。暖可乐的热能会转移到更冷的冰层,导致冰融化。可乐会失去热能,温度会下降。

    A glass of cola with ice cubes intended to show cooling down effects.

    Summary
    ::摘要

    • Heat is the transfer of thermal energy between substances. Thermal energy is the kinetic energy of moving particles of matter, measured by their temperature.
      ::热能是物质之间的热能转移,热能是物质移动微粒的动能,以温度衡量。
    • Thermal energy always moves from warmer to cooler substances until both substances have the same temperature.
      ::热能总是从温暖物质转移到冷却物质,直到两种物质温度相同。

    Review
    ::回顾

    1. Define heat.
      ::定义热量。
    2. Describe how thermal energy is transferred.
      ::描述热能是如何转移的。
    3. Hot cocoa is poured into a cold mug. Apply the concept of heat to explain what happens next. 
      ::热可可被倒入冷杯中,用热的概念来解释接下来会发生什么。