📚 IGCSE WJEC Science: Earth and Space Key Points | IGCSE WJEC 科学：地球与太空 考点精讲
This revision guide covers the essential topics for the WJEC IGCSE Science specification on Earth and Space. From the structure of our planet to the life cycles of stars, each section explains key concepts clearly for exam success.
本备考指南涵盖了 WJEC IGCSE 科学大纲中地球与太空的核心考点。从地球的内部结构到恒星的生命周期，每一节都将清晰解释关键概念，助你从容应考。
1. Earth’s Internal Structure | 地球的内部结构
The Earth is composed of several distinct layers: the inner core, outer core, mantle, and crust. The inner core is solid iron and nickel, while the outer core is liquid metal. Surrounding the core is the mantle, a thick layer of semi-molten rock called magma. The outermost layer is the thin, solid crust on which we live.
地球由几个不同的层组成：内核、外核、地幔和地壳。内核是固态的铁镍合金，外核是液态金属。地核周围是地幔，由称为岩浆的半熔融岩石构成的厚层。最外层是我们居住的薄而坚固的地壳。
The temperature increases towards the centre of the Earth, reaching about 5500 °C in the inner core. Convection currents in the mantle, caused by heat from the core, are a driving force behind plate tectonics.
从地表向地心温度逐渐升高，内核温度可达约 5500 °C。地核热量引起的地幔对流是板块构造的主要驱动力之一。
2. Plate Tectonics | 板块构造理论
The Earth’s crust and upper mantle are broken into tectonic plates that float on the semi-fluid asthenosphere. These plates move slowly – typically a few centimetres per year – due to mantle convection currents.
地壳和上地幔被分割成多个构造板块，它们漂浮在半流体的软流层上。由于地幔对流，这些板块以每年几厘米的速度缓慢移动。
Plate boundaries are classified into three main types: convergent (plates move towards each other, forming mountains or deep-ocean trenches), divergent (plates move apart, creating new crust at mid-ocean ridges), and transform (plates slide past each other, causing earthquakes).
板块边界主要分为三种类型：汇聚型（板块相互靠近，形成山脉或深海沟）、分离型（板块相互分离，在大洋中脊处形成新地壳）和转换型（板块相互错动，引发地震）。
3. Earthquakes and Volcanoes | 地震与火山
Earthquakes are caused by the sudden release of built-up stress along faults or plate boundaries. The point inside the Earth where the rupture occurs is the focus; the point directly above it on the surface is the epicentre. Seismic waves (P-waves and S-waves) travel outwards and are measured using seismometers.
地震是由于断层或板块边界积累的应力突然释放而引起的。地下发生破裂的点称为震源；震源正上方的地表点称为震中。地震波（P 波和 S 波）向外传播，由地震仪测量。
Volcanoes form when magma from the mantle rises through cracks in the Earth’s crust. Eruptions can be explosive (common at convergent boundaries with viscous magma) or effusive (at divergent boundaries or hotspots with runny lava). Volcanic activity can produce new landforms and release gases and ash into the atmosphere.
当地幔中的岩浆沿着地壳裂缝上升时，就会形成火山。喷发可以是爆炸性的（常见于汇聚边界，岩浆粘稠）或溢流性的（发生于分离边界或热点，熔岩流动性强）。火山活动可以塑造新的地貌，并向大气释放气体和火山灰。
4. The Rock Cycle | 岩石循环
Rocks are continuously transformed between three main types through the rock cycle: igneous, sedimentary, and metamorphic. Igneous rocks form when magma cools and solidifies; sedimentary rocks are created from compressed layers of sediment; metamorphic rocks result from existing rocks being altered by heat and pressure.
岩石通过岩石循环在三种主要类型之间不断转化：火成岩、沉积岩和变质岩。火成岩由岩浆冷却凝固而成；沉积岩由沉积物被压实成层而形成；变质岩则是由原岩在高温高压下变质生成。
Rock Cycle Summary | 岩石循环简表
| Process | 过程 | Change | 转化 |
|---|---|
| Cooling | 冷却 | Magma/Lava → Igneous rock |
| Weathering & Erosion | 风化与侵蚀 | Any rock → Sediment |
| Compaction & Cementation | 压实与胶结 | Sediment → Sedimentary rock |
| Heat & Pressure | 高温高压 | Any rock → Metamorphic rock |
| Melting | 熔融 | Any rock → Magma |
5. The Solar System | 太阳系
Our solar system consists of the Sun, eight planets, their moons, dwarf planets, asteroids, and comets. The four inner planets (Mercury, Venus, Earth, Mars) are rocky, while the four outer planets (Jupiter, Saturn, Uranus, Neptune) are gas giants. The asteroid belt lies between Mars and Jupiter.
我们的太阳系由太阳、八颗行星、它们的卫星、矮行星、小行星和彗星组成。内四行星（水星、金星、地球、火星）是岩石行星，外四行星（木星、土星、天王星、海王星）是气态巨行星。小行星带位于火星和木星之间。
Planets orbit the Sun in elliptical paths, held by the Sun’s gravitational pull. The further a planet is from the Sun, the longer its orbital period. Earth takes approximately 365.25 days to complete one orbit.
行星在太阳引力作用下沿椭圆轨道绕日运行。行星离太阳越远，公转周期越长。地球绕太阳一周约需 365.25 天。
6. Earth’s Movements: Day, Night and Seasons | 地球的运动：昼夜与季节
Earth rotates on its axis once every 24 hours, causing day and night. The side facing the Sun experiences day, while the opposite side is in darkness. The axis is tilted at an angle of about 23.5° relative to its orbital plane.
地球每 24 小时自转一周，产生了昼夜。面向太阳的一侧为白昼，背向太阳的一侧为黑夜。地轴相对于轨道平面倾斜约 23.5°。
This tilt, combined with Earth’s revolution around the Sun, gives rise to the seasons. When the Northern Hemisphere is tilted towards the Sun, it experiences summer with longer days and higher solar intensity; the Southern Hemisphere simultaneously has winter. Six months later, the situation reverses.
这种倾斜加上地球绕太阳的公转，形成了四季。当北半球倾向太阳时，那里是夏季，白昼更长，日照更强；此时南半球是冬季。六个月后，情况会反过来。
7. The Moon and Tides | 月球与潮汐
The Moon is Earth’s only natural satellite, orbiting at an average distance of about 384,400 km. It does not produce its own light but reflects sunlight. The Moon’s phases (new moon, first quarter, full moon, last quarter) result from the changing relative positions of the Earth, Moon, and Sun.
月球是地球唯一的天然卫星，平均距离地球约 384,400 公里。它本身不发光，而是反射太阳光。月相（新月、上弦月、满月、下弦月）是由于地球、月球和太阳三者相对位置的改变而产生的。
Tides on Earth are caused mainly by the gravitational pull of the Moon, and to a lesser extent the Sun. The side of Earth facing the Moon experiences a high tide due to the Moon’s gravity pulling the water. A second high tide occurs on the opposite side due to inertia. Spring tides (higher than normal) occur when the Sun, Earth, and Moon are aligned; neap tides (lower) occur when they form a right angle.
地球上的潮汐主要由月球的引力所致，太阳的影响次之。地球朝向月球的一侧因月球引力吸引水体而出现高潮；对侧因惯性作用也产生一个高潮。当太阳、地球和月球排成一线时，出现大潮（潮差更大）；当三者形成直角时，出现小潮（潮差更小）。
8. The Life Cycle of Stars | 恒星的生命周期
Stars form from vast clouds of gas and dust called nebulae. Gravity pulls the material together, forming a protostar. When the core temperature reaches about 10 million °C, nuclear fusion of hydrogen into helium begins, and a main-sequence star is born. The Sun is a main-sequence star.
恒星诞生于称为星云的巨大气体和尘埃云。引力将物质聚集在一起，形成原恒星。当核心温度达到约一千万°C 时，氢聚变为氦的核反应开始，一颗主序星诞生了。太阳就是一颗主序星。
When a star’s hydrogen fuel runs out, its fate depends on its mass. Low-mass stars like the Sun expand into a red giant, then shed their outer layers, leaving a white dwarf. More massive stars become red supergiants and end in a supernova explosion. The remnant can be a neutron star or, if the original mass was even larger, a black hole.
当恒星中的氢燃料耗尽后，其命运取决于质量。像太阳这样的低质量恒星会膨胀为红巨星，然后抛掉外层，留下白矮星。质量更大的恒星会变成红超巨星，最终发生超新星爆发。剩余的核心可能成为中子星，如果原恒星质量更大，则会坍缩成黑洞。
9. The Origin of the Universe: The Big Bang | 宇宙的起源：大爆炸
The Big Bang theory states that the Universe began from an extremely hot and dense point about 13.8 billion years ago. It has been expanding ever since. Key evidence includes the redshift of light from distant galaxies (showing they are moving away) and the cosmic microwave background radiation (uniform radiation left over from the early hot phase).
大爆炸理论认为，宇宙起源于约 138 亿年前的一个极热极密的点，并自此不断膨胀。关键证据包括：来自遥远星系的光发生红移（表明它们正在远离），以及宇宙微波背景辐射（早期炽热阶段遗留下来的均匀辐射）。
Redshift occurs because the wavelength of light is stretched as the source moves away, shifting it towards the red end of the spectrum. The faster a galaxy recedes, the greater its redshift – a relationship described by Hubble’s Law.
红移的产生是因为光源远离时，光的波长被拉长，谱线向光谱的红端移动。星系远离的速度越快，其红移越大——这一关系由哈勃定律描述。
10. Artificial Satellites and Space Exploration | 人造卫星与太空探索
Artificial satellites orbit Earth for purposes such as communication, weather monitoring, navigation (GPS), and scientific research. They are launched into different orbits: low Earth orbit (LEO) for imaging satellites, geostationary orbit (GEO) for communications, and polar orbits for global coverage.
人造卫星环绕地球运行，用于通信、气象监测、导航（GPS）和科学研究等目的。它们被发射到不同的轨道：低地球轨道（LEO）用于成像卫星，地球静止轨道（GEO）用于通信，极地轨道用于全球覆盖。
Space exploration, using probes, rovers, and crewed missions, has vastly increased our understanding of the solar system. Landers have visited Mars, and probes have flown past all eight planets. The International Space Station (ISS) serves as a laboratory for studying the effects of microgravity on biological and physical systems.
通过探测器、漫游车和载人飞行任务进行的太空探索，极大地增进了我们对太阳系的了解。着陆器已登陆火星，探测器已飞越全部八颗行星。国际空间站（ISS）作为一个实验室，用于研究微重力对生物和物理系统的影响。
Challenges of space travel include extreme temperatures, radiation, microgravity health effects, and the need for sustainable life-support systems. Future missions aim to return humans to the Moon and eventually send astronauts to Mars.
太空旅行的挑战包括极端温度、辐射、微重力对健康的影响，以及需要可持续的生命支持系统。未来的任务旨在让人类重返月球，最终将宇航员送上火星。
Published by TutorHao | Science Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导Cancel reply