📚 Energy Transfers, Efficiency and Insulation | 能量传递、效率与保温
In IGCSE Science, energy transfer is one of the most frequently examined topics. It connects physics, chemistry and biology, and it appears in questions about food chains, chemical reactions, power stations and home insulation. This revision article explains the key ideas you need to master for Edexcel IGCSE Science, with special attention to reducing unwanted thermal energy transfers.
在 IGCSE 科学中，能量传递是最常考的主题之一。它将物理、化学和生物联系起来，出现在食物链、化学反应、发电站和家庭保温等题目中。这篇复习文章为你讲解 Edexcel IGCSE 科学的核心概念，并特别关注如何减少不必要的热能传递。
1. The Principle of Conservation of Energy | 能量守恒定律
Energy cannot be created or destroyed. It can only be transferred from one store to another, or converted between different forms. In a closed system, the total amount of energy remains constant.
能量既不能被创造，也不能被消灭。它只能从一个储存器转移到另一个储存器，或在不同形式之间转换。在封闭系统中，能量的总量始终保持不变。
For example, when an object falls, gravitational potential energy is converted to kinetic energy. When a battery lights a bulb, chemical energy is transferred to light energy and thermal energy. The total energy before the transfer equals the total energy after the transfer, including energy that is dissipated to the surroundings.
例如，当物体下落时，重力势能转化为动能。当电池点亮灯泡时，化学能转化为光能和热能。能量转化前的总量等于转化后的总量，包括耗散到周围环境中的能量。
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A falling ball: gravitational potential energy → kinetic energy + thermal energy (due to air resistance).
下落的球：重力势能 → 动能 + 热能（由于空气阻力）。
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A simple pendulum: energy continually changes between kinetic energy and gravitational potential energy, with a small thermal energy loss at each swing.
单摆：能量在动能与重力势能之间不断转化，每次摆动都会损耗少量热能。
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An electric heater: electrical energy → thermal energy, which is the intended output but not a useful output in every situation.
电暖器：电能 → 热能，这是预期的输出，但在某些情况下不一定是“有用的”输出。
2. Energy Stores | 能量储存形式
Edexcel IGCSE Science expects you to recognise and name the main energy stores. Using the correct store names is essential for full marks in exam questions.
Edexcel IGCSE 科学要求你能够识别并说出主要的能量储存形式。在考试中使用正确的储存名称是获得满分的关键。
| Energy store | 能量储存 | Meaning | 含义 | Example | 例子 |
|---|---|---|
| Chemical | 化学能 | Energy stored in chemical bonds | 储存在化学键中的能量 | Food, batteries, fuel | 食物、电池、燃料 |
| Kinetic | 动能 | Energy an object has because of its motion | 物体因运动而具有的能量 | Moving car, flowing water | 行驶的汽车、流动的水 |
| Gravitational potential | 重力势能 | Energy stored due to height above the ground | 物体因高于地面而储存的能量 | Water in a dam, a raised weight | 水坝中的水、被举高的重物 |
| Elastic potential | 弹性势能 | Energy stored in a stretched or compressed material | 拉伸或压缩材料中储存的能量 | Stretched spring, compressed football | 拉伸的弹簧、被压紧的足球 |
| Thermal | 热能 | Energy associated with the temperature of an object | 与物体温度相关的能量 | Hot water, warm air | 热水、温暖的空气 |
| Nuclear | 核能 | Energy stored in the nucleus of an atom | 储存在原子核中的能量 | Uranium inside a nuclear reactor | 核反应堆中的铀 |
3. Ways Energy Can Be Transferred | 能量传递的方式
Energy can be transferred
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