Year 7 Cambridge Physics: International Competition Preparation Guide | 剑桥7年级物理：国际竞赛备战攻略

📚 Year 7 Cambridge Physics: International Competition Preparation Guide | 剑桥7年级物理：国际竞赛备战攻略

International physics competitions provide a fantastic opportunity for Year 7 students to stretch their scientific thinking beyond the classroom. This guide is designed to help Cambridge Lower Secondary learners prepare effectively, covering key topics, problem-solving strategies and essential mindsets.

国际物理竞赛为 7 年级学生提供了一个将科学思维拓展到课堂之外的绝佳机会。本攻略旨在帮助剑桥初中学习者有效备战，涵盖核心知识点、解题策略和必要的心理建设。

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1. Understanding the Competition Landscape | 了解竞赛格局

The British Physics Olympiad (BPhO) Junior Physics Challenge is one of the most accessible events for Years 7–8. The online paper consists of 25 multiple-choice questions to be solved in 50 minutes, testing exactly the same concepts you meet in Cambridge Stage 7 Science: forces, energy, electricity, waves and matter. Success in this challenge signals a strong grasp of fundamentals and the ability to apply them in unfamiliar contexts.

英国物理奥林匹克初级物理挑战赛（BPhO Junior Physics Challenge）是最适合 7–8 年级学生的赛事之一。线上试卷包含 25 道选择题，限时 50 分钟，考察的内容正是你在剑桥科学 Stage 7 中学到的力、能量、电、波、物质等概念。在这一挑战中取得好成绩，表明你不仅基础扎实，还能灵活运用。

The Australian Big Science Competition (Physics section) takes a scenario-based approach. You might be asked to decide why a lunar eclipse looks red or to predict the motion of a toy car on a ramp. Such competitions nurture scientific curiosity and problem-solving skills that perfectly complement the Cambridge curriculum.

澳大利亚大科学竞赛的物理板块则采用情境式命题。你可能会被问到月球食为何呈红色，或者需要预测玩具小车在斜面上的运动。这类竞赛培养的科学好奇心与解题能力，正是剑桥课程的有力补充。

Even within your own school, many teachers organise Physics Olympiad club sessions or celebrate British Science Week with internal challenges. Taking part in these low-stakes events builds confidence and exam technique before you enter a formal competition.

即便在你自己的学校，许多老师也会组织物理奥赛俱乐部或在英国科学周期间举办校内挑战赛。参与这些低压力的活动能在你正式参加竞赛前建立信心并熟悉答题技巧。

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2. Core Topic Checklist | 核心知识点清单

Forces and Motion: Speed = distance ÷ time, distance–time graphs, balanced and unbalanced forces, gravity, friction, air resistance.

力与运动：速度 = 距离 ÷ 时间，距离–时间图，平衡力与不平衡力，重力，摩擦力，空气阻力。

Energy: Different energy stores (kinetic, thermal, chemical, gravitational potential, elastic), energy transfers, conservation of energy, work done = force × distance moved in the direction of the force.

能量：不同能量储存（动能、热能、化学能、重力势能、弹性势能），能量转移，能量守恒，做功 = 力 × 沿力方向移动的距离。

Electricity: Simple circuit symbols, current as flow of charge, voltage (potential difference), resistance, conductors and insulators, series and parallel circuits.

电学：简单电路符号，电流即电荷的流动，电压（电势差），电阻，导体与绝缘体，串联电路与并联电路。

Magnetism: Magnetic poles (attraction/repulsion), magnetic fields, electromagnets and their uses, the Earth’s magnetic field.

磁学：磁极（吸引/排斥），磁场，电磁铁及其用途，地磁场。

Waves and Sound: Sound produced by vibrations, how sound travels through different media, speed of sound, light travels in straight lines, reflection, refraction basics.

波与声音：振动产生声音，声音在不同介质中的传播，声速，光沿直线传播，反射，折射基础。

Matter and Density: Particle model for solids, liquids and gases, density = mass ÷ volume, changes of state, expansion and contraction.

物质与密度：固体、液体和气体的粒子模型，密度 = 质量 ÷ 体积，物态变化，热胀冷缩。

Earth and Space: Gravity on Earth and in space, the Solar System, day and night caused by Earth’s rotation, seasons due to tilt of the axis.

地球与太空：地球与太空中的重力，太阳系，地球自转导致昼夜交替，地轴倾斜形成四季。

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3. Mastering Fundamental Concepts | 掌握基本概念

Competition questions rarely ask for word-for-word definitions. Instead, they test whether you can use a concept to explain a new situation. For example, rather than simply stating ‘friction opposes motion’, you may need to explain why tyres are made of rubber with deep treads – because high friction stops cars from skidding on wet roads.

竞赛题很少直接考定义，而是考察你能否用概念解释新场景。例如，与其复述“摩擦阻碍运动”，你可能需要解释为何轮胎用橡胶并带有深纹路——因为高摩擦力可防止汽车在湿滑路面上打滑。

Build mental models for abstract ideas. For current electricity, picture a flow of charged particles (electrons) pushed by a battery. This image helps you instantly understand why a break in a circuit stops all bulbs, while in parallel circuits one faulty branch does not disrupt the others.

为抽象概念建立心像模型。对于电流，可以想象成电池推动的带电粒子（电子）流。这个画面能让你立刻明白为什么串联电路中一处断开所有灯泡都熄灭，而并联电路中某一支路故障不影响其它支路。

Temperature and heat are often confused. Temperature measures how hot an object is, while heat is the thermal energy transferred from a hotter body to a cooler one. A competition might present a thermogram image and ask you to infer where heat is being lost from a house – showing that you understand heat flow, not just temperature values.

温度和热量常被混淆。温度衡量物体的冷热程度，而热量是从高温物体传递到低温物体的热能。竞赛中可能出现热成像图，让你推断房屋哪里正在散失热量——这要求你真正理解热传递，而非只看温度数值。

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4. Developing Problem-Solving Skills | 培养解题技巧

Follow a five-step routine for every numerical problem. (1) Read the question twice and underline the data. (2) Draw a labelled sketch if it helps. (3) Choose the correct formula that links the given quantities. (4) Substitute values with their units and calculate carefully. (5) Check if the answer is sensible in the real world.

每道计算题都遵循五步法。（1）读题两遍，划出数据。（2）如有需要，画出带标注的示意图。（3）选出与已知量关联的正确公式。（4）代入数值并带单位计算。（5）检查答案在现实中是否合理。

v = d ÷ t

Example: A cyclist travels 30 km in 2 hours. Find her average speed in km/h. Solution: v = 30 km ÷ 2 h = 15 km/h. This fits the rule because speed, distance and time are all given in sensible units.

示例：一名骑行者 2 小时行驶 30 km。求平均速度（km/h）。解：v = 30 km ÷ 2 h = 15 km/h。因为速度、距离和时间单位匹配，答案合理。

ρ = m ÷ V

Example: A metal block has a mass of 120 g and a volume of 40 cm³. Find its density in g/cm³. Solution: ρ = 120 g ÷ 40 cm³ = 3 g/cm³. The block will sink in water because its density is greater than 1 g/cm³.

示例：一金属块质量为 120 g，体积为 40 cm³。求密度（g/cm³）。解：ρ = 120 g ÷ 40 cm³ = 3 g/cm³。该金属块密度大于 1 g/cm³，会在水中下沉。

Always convert to consistent units before calculating. If a force of 50 N presses on an area of 0.2 m², pressure p = 50 N ÷ 0.2 m² = 250 Pa. If the area had been given as 2000 cm², you would first convert to m² (2000 cm² = 0.2 m²).

计算前务必统一单位。若 50 N 的力作用于 0.2 m² 的面积上，压强 p = 50 N ÷ 0.2 m² = 250 Pa。如果面积给的是 2000 cm²，你需要先换算（2000 cm² = 0.2 m²）。

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5. Tackling Experimental and Practical Questions | 应对实验与实践题

Many competitions ask you to interpret data from a simple experiment, such as stretching a spring. The table below shows a typical set of results for load and extension.

许多竞赛题目要求你解读简单实验的数据，比如弹簧拉伸实验。下表展示了一组典型的负载与伸长量数据。

Load (N)	Extension (cm)
0	0.0
2	3.2
4	6.5
6	9.7

Plotting extension against load yields a straight line through the origin, which obeys Hooke’s law. You can calculate the spring constant by taking the slope: for a 4 N increase, the extension rises by about 6.5 cm, so the constant is approximately 0.62 N/cm. Such analysis is a favourite in competition papers.

将伸长量对应负载作图，得到一条过原点的直线，符合胡克定律。你可以通过斜率求出弹簧常数：负载增加 4 N 时伸长量约增加 6.5 cm，所以常数约为 0.62 N/cm。这类分析是竞赛试卷中的常见题型。

Be ready to spot anomalous results. If one extension was recorded as 8.0 cm for a 4 N load while all other readings lie on a straight line, you should identify it as an outlier and possibly exclude it from your graph. Justify why – perhaps the spring wobbled or the ruler was misread.

要学会识别异常数据。如果在 4 N 时记录到的伸长量为 8.0 cm，而其他数据点都在一条直线上，你应该将它视为异常值，作图时可以剔除。还要说明原因——可能是弹簧晃动或尺子读数错误。

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6. Time Management and Exam Strategy | 时间管理与应考策略

Junior competitions are fast-paced. With 25 questions in 50 minutes, you have an average of only two minutes per question. Start by scanning the entire paper and ticking the ones you find easiest. Answer these first to secure marks quickly.

初级竞赛节奏很快。50 分钟完成 25 道题，平均每题只有两分钟。拿到试卷后先快速浏览，勾出你认为最简单的题目，优先作答，快速锁定分数。

Published by TutorHao | Year 7 Physics Revision Series | aleveler.com

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