Year 7 SQA Physics: Key Concepts Overview | 苏格兰SQA七年级物理：核心知识点梳理

📚 Year 7 SQA Physics: Key Concepts Overview | 苏格兰SQA七年级物理：核心知识点梳理

This guide brings together the essential physics topics covered in Year 7 under the Scottish SQA curriculum. From forces and energy to electricity and space, it provides clear, bilingual explanations to help students consolidate key concepts and prepare confidently for assessments.

本指南汇集了苏格兰SQA课程七年级物理的核心主题，涵盖力、能量、电学和宇宙等内容，以清晰的双语讲解帮助学生巩固重点知识，为测评做好充分准备。

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1. Forces and Motion | 力与运动

A force is simply a push or a pull acting on an object. Forces can change the shape of an object, make it start moving, speed up, slow down, or change direction.

力是对物体的推或拉的作用。力可以改变物体的形状，使其开始运动、加速、减速或改变方向。

The speed of an object tells us how far it travels in a certain time. The relationship is given by speed = distance ÷ time. Speed is measured in metres per second (m/s) or kilometres per hour (km/h).

速度表示物体在一定时间内运动的距离。关系式为 速度 = 距离 ÷ 时间。速度的单位是米每秒（m/s）或千米每小时（km/h）。

When an object is not moving, it is stationary and has a speed of zero. A distance–time graph can show motion: a horizontal line means the object is stationary, and a steeper line means a faster speed.

当物体不动时，它是静止的，速度为零。距离-时间图可以表示运动情况：水平线表示物体静止，线段越陡表示速度越快。

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2. Balanced and Unbalanced Forces | 平衡力与不平衡力

When two forces acting on an object are equal in size and opposite in direction, they are balanced. Balanced forces do not cause a change in motion – the object remains stationary or continues moving at a constant speed.

当作用在物体上的两个力大小相等、方向相反时，它们相互平衡。平衡力不会改变物体的运动状态——物体保持静止或匀速运动。

When forces are unbalanced, there is a net force acting on the object. This net force can cause the object to accelerate (speed up), decelerate (slow down) or change direction.

当力不平衡时，物体受到合力作用。这个合力会使物体加速、减速或改变运动方向。

A tug of war is a good example: if both teams pull with the same force, the rope does not move. If one team pulls harder, the forces become unbalanced and the rope moves toward the stronger team.

拔河是一个很好的例子：如果两队用同样大小的力拉，绳子不动；如果一队拉力更大，力就不平衡，绳子会向力量更大的一方移动。

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3. Friction and Air Resistance | 摩擦力与空气阻力

Friction is a contact force that opposes motion between two surfaces. It occurs because surfaces are never perfectly smooth. Friction can be useful, such as when it helps us walk without slipping, or it can be unwanted, such as when it causes wear in engine parts.

摩擦力是一种阻碍两个接触面之间相对运动的力。它产生的原因是表面从来不是绝对光滑的。摩擦力可能有用，比如帮助我们走路不打滑；也可能有害，比如造成发动机零件磨损。

Air resistance (or drag) is a type of friction that acts on objects moving through air. The faster an object moves, the greater the air resistance. Streamlined shapes reduce air resistance, which is why racing cars and aeroplanes have smooth, curved bodies.

空气阻力（或阻力）是物体在空气中运动时受到的摩擦力。速度越快，空气阻力越大。流线型外形可以减少空气阻力，这就是赛车和飞机设计成光滑曲面体形的原因。

Lubricants like oil can reduce unwanted friction between solid surfaces, and parachutes deliberately use air resistance to slow down a falling person.

润滑油等润滑剂可以减少固体表面间的不必要摩擦，而降落伞则有意识地利用空气阻力减缓人下落的速度。

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4. Gravity, Mass and Weight | 重力、质量与重量

Gravity is a non-contact force of attraction between objects that have mass. On Earth, gravity pulls objects towards the centre of the planet, which is why things fall downwards.

重力是具有质量的物体之间的一种非接触吸引力。在地球上，重力将物体拉向地心，这就是物体下落的原因。

Weight is the force due to gravity acting on an object. It is calculated using weight = mass × gravitational field strength, where gravitational field strength (g) on Earth is about 10 N/kg. Weight is measured in newtons (N) using a spring balance, while mass is measured in kilograms (kg).

重量是作用在物体上的重力。计算公式为 重量 = 质量 × 重力场强，地球表面重力场强（g）约为 10 N/kg。重量用弹簧秤测量，单位是牛顿（N）；质量则用千克（kg）表示。

Mass is the amount of matter in an object and does not change regardless of location. Weight, however, would be different on the Moon because the Moon’s gravity is weaker.

质量是物体所含物质的多少，不随位置改变。但重量在月球上会不同，因为月球引力较小。

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5. Energy Forms and Energy Transfers | 能量形式与能量转化

Energy exists in many forms, including kinetic energy (movement), gravitational potential energy (stored in an object raised above the ground), elastic potential energy (stored in stretched or compressed objects), thermal energy (heat), chemical energy, electrical energy, light energy and sound energy.

能量有多种形式，包括动能（运动）、重力势能（物体因被举高而储存的能量）、弹性势能（拉伸或压缩物体储存的能量）、热能（热）、化学能、电能、光能和声能。

The law of conservation of energy states that energy cannot be created or destroyed; it can only be transferred from one form to another or moved from one place to another. For example,

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