📚 Year 11 WJEC Science: Common Misconceptions and Corrections | Year 11 WJEC 科学：常见误区与纠正方法
In Year 11 WJEC Science, students often find that deeply held misconceptions can block a real understanding of key concepts. This article identifies ten of the most frequent errors in biology, chemistry and physics, and shows how to replace them with correct scientific thinking. Each section pairs a common misunderstanding with a thorough correction, helping you build a more accurate mental model for your exams.
在 Year 11 WJEC 科学课程中，学生经常发现根深蒂固的错误观念会阻碍对核心概念的正确理解。本文列出生物、化学和物理中最常见的十个误区，并展示如何用正确的科学思维方式取而代之。每个小节都将常见误解与详细纠正配对，帮助你为考试建立更准确的心智模型。
1. Forces and Motion | 力与运动
Many students believe that a constant force must act on an object to keep it moving in a straight line. This idea comes from everyday experience, where friction always slows things down, but it contradicts Newton's first law.
许多学生认为物体要保持直线运动必须持续受到一个恒定的力。这个想法来自日常经验——摩擦力总让物体慢下来——但它违背了牛顿第一定律。
In the absence of a resultant force, an object will remain at rest or continue to move at a constant velocity. The force is needed to overcome friction or to change the velocity (i.e., to accelerate), not to maintain steady motion.
在没有合外力的情况下，物体会保持静止或匀速直线运动。力需要用来克服摩擦或者改变速度（即产生加速度），而不是用来维持稳定的运动状态。
uth, a constant resultant force causes a constant acceleration, as described by F = m × a.
另一个相关错误是认为恒定的力产生恒定的速度。实际上，恒定的合外力导致恒定的加速度，正如公式 F = m × a 所描述。
2. Gravity and Free Fall | 重力与自由落体
A widespread misconception is that heavier objects fall faster than lighter ones. Pupils often cite a bowling ball and a feather, forgetting the role of air resistance.
一个普遍的误解是重物比轻物下落更快。学生们常举保龄球和羽毛的例子，却忘了空气阻力所起的作用。
.8 m/s²), regardless of their mass. The famous Apollo 15 experiment on the Moon, where a hammer and a feather hit the surface simultaneously, is the best proof.
在真空中，所有物体都以同样的加速度向地球下落（g ≈ 9.8 m/s²），与它们的质量无关。阿波罗 15 号在月球上进行的锤子和羽毛同时落地的著名实验就是最好的证明。
Air resistance can create a terminal velocity where the weight is balanced by drag, leading to the illusion that weight determines speed. Understanding resultant forces resolves the confusion.
空气阻力会造成终端速度，此时重力与空气阻力平衡，导致重量决定下降速度的错觉。理解合外力的概念就能消除这一困惑。
3. Electric Circuits | 电路
One of the hardiest misconceptions is that electric current gets 'used up' as it passes around a circuit, so less current returns to the battery than leaves it. This model would mean current is not conserved, which is false.
最顽固的误区之一是电流在电路中流动时会被“消耗”，因此返回电池的电流少于从电池出来的电流。这种模型意味着电流不守恒，这是错误的。
In a series circuit, the current is the same at all points. The power supply provides energy to the charges, but the number of mobile charge carriers passing any point per second (the current) remains constant. The energy is transferred to the components, not the current itself.
在串联电路中，各处电流大小相同。电源为电荷提供能量，但每秒钟通过任何一点的移动电荷载流子的数量（即电流）保持不变。能量被转移到各个元件，而不是电流本身被消耗。
A helpful analogy is a bicycle chain: the links all move at the same rate, but energy is delivered to the back wheel where it is transformed. Ammeters placed before and after a bulb give identical readings in a simple circuit.
一个有用的类比是自行车链条：所有链节以相同速率移动，但能量被传递到后轮并被转化。在简单电路中，放置在灯泡前后的电流表会显示相同的读数。
4. Energy Transfers | 能量转移
Students frequently say that energy is 'used up' or 'lost' when a device operates. This phrasing implies that energy vanishes, which contradicts the principle of conservation of energy.
学生们常常说，当设备工作时能量被“用光”或“损耗”。这种说法意味着能量消失了，这与能量守恒定律相矛盾。
Energy is never created or destroyed, only transferred between stores. In a lamp, energy is transferred electrically from the battery to the thermal and light stores of the surroundings. The total energy remains the same, but it becomes more spread out and less useful for doing work.
能量既不会凭空产生也不会凭空消失，它只在不同的能量库之间转移。在灯泡中，能量通过电的方式从电池转移到周围环境的热能和光能库。总能量保持不变，只是变得更加分散，做功的能力下降。
Learning to describe processes in terms of energy stores and pathways (electrically, by heating, by radiation, mechanically) rather than using the word 'lost' is a crucial exam skill for WJEC Science.
学会用能量库和能量转移途径（电、加热、辐射、机械）来描述过程，而不是使用“损失”这个词，是 WJEC 科学中一项关键的考试技能。
5. Particle Model and Thermal Expansion | 粒子模型与热膨胀
A very common visual mistake is to imagine that the particles themselves (atoms or molecules) get bigger when a substance is heated. This leads to poor explanations of thermal expansion and changes of state.
一个非常常见的形象化错误是，认为物质受热时粒子（原子或分子）本身变大了。这导致对热膨胀和状态变化的解释非常糟糕。
Individual particles do not expand; their size remains effectively constant. When heated, particles gain kinetic energy and vibrate more vigorously or move faster. In solids and liquids, this increased vibration pushes particles slightly further apart, so the whole material expands.
单个粒子并不膨胀；它们的大小基本保持不变。受热时，粒子获得动能，振动更剧烈或移动更快。在固体和液体中，这种加剧的振动将粒子略微推开，使整体材料膨胀。
During a state change from liquid to gas, the particles do not swell into bubbles; instead, they overcome the attractive forces holding them together and move far apart, greatly increasing the volume. The mass, and the number of particles, stays constant.
在从液体到气体的状态变化中，粒子并不会膨胀成气泡；相反，它们克服了将它们束缚在一起的吸引力，彼此远离，体积大幅增加。质量以及粒子的数量保持不变。
6. Chemical Bonding and Structure | 化学键合与结构
Many candidates mix up the properties of ionic and covalent substances because they imagine all chemicals as tiny molecules. The belief that sodium chloride contains NaCl molecules is a classic error.
许多考生混淆了离子化合物和共价化合物的性质，因为他们把所有化学物质都想象成微小的分子。认为氯化钠含有 NaCl 分子就是一个经典错误。
Ionic compounds form giant lattices of oppositely charged ions held together by strong electrostatic forces. There are no individual molecules; the formula NaCl simply shows the ratio of ions. This explains why ionic solids have high melting points and conduct electricity only when molten or in solution.
离子化合物形成由带相反电荷的离子组成的巨型晶格，靠强大的静电力结合在一起。没有单独的分子；NaCl 化学式仅仅表示离子的比例。这解释了为什么离子固体熔沸点高，并且只在熔融或溶于水时导电。
To clarify, here is a comparison of the two main types of structure often confused in questions:
为了澄清，下面用表格对比题目中经常混淆的两类结构：
| Misconception | Correct Understanding |
|---|---|
| 'Ionic compounds are made of molecules.' '离子化合物由分子构成。' | Ionic substances consist of a giant ionic lattice with a regular repeating pattern of ions. 离子物质由巨型离子晶格构成，离子呈规则重复排列。 |
| 'All covalent substances are small molecules.' '所有共价物质都是小分子。' | Some covalent substances are giant covalent structures (e.g. diamond, silica), with very high melting points. 有些共价物质是巨型共价结构（如金刚石、二氧化硅），具有极高的熔点。 |
| 'Covalent bonds are weak.' '共价键很弱。' | Covalent bonds are strong, but intermolecular forces between simple molecules are weak. 共价键本身很强，但简单分子之间的分子间作用力很弱。 |
7. Acids, Alkalis and Neutralisation | 酸、碱与中和反应
'Neutralisation always makes a neutral solution' is a statement many students would accept without hesitation. This misconception can lead them to draw incorrect conclusions about pH curves and salt solutions.
“中和反应总是生成中性溶液”，许多学生会毫不犹豫地接受这个说法。这个误区可能导致他们对 pH 曲线和盐溶液作出错误的推断。
Neutralisation refers to the chemical reaction between an acid and a base to produce a salt and water. However, the final pH depends on the parent acid and base. The salt of a strong acid and a weak base will be acidic; the salt of a weak acid and a strong base will be alkaline. Only a strong acid–strong base combination gives a perfectly neutral salt solution at the equivalence point.
中和指的是酸与碱反应生成盐和水的化学过程。但是，最终的 pH 取决于母体酸和碱。强酸与弱碱生成的盐显酸性；弱酸与强碱生成的盐显碱性。只有强酸和强碱的组合才能在等当点处产生真正中性的盐溶液。
For example, ammonium chloride (from hydrochloric acid and ammonia solution) has a pH less than 7, while sodium ethanoate (from ethanoic acid and sodium hydroxide) is alkaline. Understanding salt hydrolysis helps explain these observations.
例如，氯化铵（由盐酸和氨水反应）的 pH 小于 7，而乙酸钠（由乙酸和氢氧化钠反应）显碱性。理解盐的水解有助于解释这些现象。
8. Photosynthesis and Respiration in Plants | 植物的光合作用与呼吸作用
A deeply embedded idea is that plants only carry out respiration at night, while photosynthesis happens during the day. This separates the two processes incorrectly in time and can cause problems in data interpretation questions.
一个根深蒂固的观念是植物只在夜间进行呼吸作用，而光合作用发生在白天。这错误地将两个过程在时间上分开，可能在数据分析题中造成问题。
Plants respire continuously, 24 hours a day, like all living cells. Respiration releases energy from glucose for growth and maintenance. During daylight, photosynthesis proceeds at a high rate, typically producing more oxygen than respiration consumes, giving a net release of oxygen. At night, only respiration occurs, leading to a net uptake of oxygen and release of carbon dioxide.
植物像所有活细胞一样，一天 24 小时不间断地进行呼吸作用。呼吸作用从葡萄糖中释放能量用于生长和维持生命。白天，光合作用以高速率进行，通常产生的氧气多于呼吸作用消耗的氧气，因而净释放氧气。到了夜间，只发生呼吸作用，导致净吸收氧气、释放二氧化碳。
The compensation point is the light intensity at which photosynthetic oxygen production exactly matches respiratory oxygen use. Distinguishing net gas exchange from underlying processes is essential for explaining pondweed experiment results.
补偿点是光合氧气产量与呼吸氧气消耗量恰好相等时的光照强度。区分净气体交换与基础的过程，对于解释水草实验的结果至关重要。
9. Genetics and Inheritance | 遗传与变异
Many learners equate 'dominant allele' with 'most common in a population'. This leads to the false expectation that conditions like polydactyly (extra fingers) must be widespread because it is dominant.
很多学习者把“显性等位基因”等同于“在种群中最常见”。这导致一个错误的预期，即像多指症（额外的手指）这样的特征必定广泛存在，因为它是显性的。
Dominance describes the relationship between alleles in a heterozygous individual: a dominant allele is expressed in the phenotype whenever it is present. It says nothing about how frequent the allele is in the gene pool. Polydactyly is indeed dominant but quite rare, while many recessive traits, such as blood type O, are very common.
显性描述的是杂合个体中等位基因之间的关系：只要存在显性等位基因，它就会在表型中显现。这与该等位基因在基因库中的频率无关。多指症确实是显性遗传，但相当罕见，而许多隐性性状，如 O 型血，却非常普遍。
A related misconception is that inherited characteristics acquired during a parent's lifetime can be passed on (Lamarckism). The modern understanding is that only changes to DNA in gametes are inherited, and environmental effects do not change the genes themselves unless a mutation occurs.
一个相关的误区是，父母一生中获得的后天特征可以遗传（拉马克学说）。现代遗传学理解是，只有配子中 DNA 的变化才能遗传，环境影响本身并不会改变基因，除非发生突变。
10. Scientific Thinking and Investigative Skills | 科学思维与研究技能
Confusing correlation with causation is a mistake that affects both written explanations and the evaluation of experimental evidence. 'The data show a link, so one thing must cause the other' is a premature jump.
混淆相关性与因果关系是一个既影响书面解释又影响实验证据评估的错误。“数据显示有关联，所以一方必然导致另一方”是一个过早的跳跃。
A correlation simply means two variables change together. This could be due to one causing the other, a third factor influencing both, or pure coincidence. To establish causation, scientists need a controlled experiment that isolates the independent variable and rules out confounding variables.
相关性仅仅意味着两个变量一起变化。这可能是由于一方导致另一方，也可能是第三方因素同时影响双方，或者纯粹是巧合。要确立因果关系，科学家需要对照实验，将自变量分离出来，并排除混杂变量。
A classic classroom example is the strong positive correlation between ice cream sales and drowning incidents. It would be wrong to conclude that ice cream causes drowning; the lurking variable is hot weather, which increases both swimming and ice cream consumption.
课堂上的经典例子是冰淇淋销量与溺水事件之间的正相关性。如果因此得出冰淇淋导致溺水的结论就大错特错了；隐藏变量是炎热的天气，它同时增加了游泳和冰淇淋消费。
When evaluating WJEC practical tasks, always ask: was the experiment fair? Were all variables controlled? Acknowledging that correlation is not causation strengthens any conclusion.
在评估 WJEC 实践任务时，一定要问：实验是否公平？所有变量是否得到控制？承认相关不等于因果会强化任何结论。
Published by TutorHao | Science Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图