Magnetism · 磁性
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| magnet/ˈmæɡnɪt/ | 磁体 | cí tǐ |
| poles/pəʊlz/ | 磁极 | cí jí |
| magnetic field/mæɡˈnetɪk fiːld/ | 磁场 | cí chǎng |
| permanent magnet/ˈpɜːmənənt ˈmæɡnɪt/ | 永磁体 | yǒng cí tǐ |
| induced magnetism/ɪnˈdjuːst ˈmæɡnɪtɪzəm/ | 感应磁性 | gǎn yìng cí xìng |
| soft iron/sɒft ˈaɪən/ | 软铁 | ruǎn tiě |
| field lines/fiːld laɪnz/ | 磁感线 | cí gǎn xiàn |
| electromagnets/ɪˌlektrəʊˈmæɡnɪts/ | 电磁铁 | diàn cí tiě |
The pull of a magnet 磁体
- A fridge magnet sticks; a compass needle always swings to point north.
- A magnet has two ends, called poles 磁极: a north (N) and a south (S).
- Let's see the rules magnets follow — and how to picture their invisible field.
一块磁铁的吸引
- 一块冰箱磁铁粘住;一根指南针针总是摆动指向北。
- 一块磁铁(magnet)有两端,叫做磁极(poles):一个北(N)和一个南(S)。
- 让我们看看磁铁遵循的规则——以及如何描绘它们看不见的场。
Poles and magnetic materials
- The pole rule is like the charge rule:
- Same poles (N–N or S–S) repel (push apart).
- Different poles (N–S) attract (pull together).
- A magnet attracts magnetic materials: iron, steel, cobalt, nickel. Copper, plastic and wood are not magnetic.
Iron filings line up along the magnetic field 磁场 of a bar magnet
磁极与磁性材料
- 磁极规则像电荷规则:
- 相同的磁极(N–N 或 S–S)排斥(推开)。
- 不同的磁极(N–S)吸引(拉到一起)。
- 一块磁铁吸引磁性材料:铁、钢、钴、镍。铜、塑料和木头不是磁性的。
铁屑沿一块条形磁铁的磁场排列
Make the magnetic field visible · 让磁场可见
Compass needles trace the field from N to S; switch between attract and repel and watch the whole pattern reorganise, with a neutral point appearing for like poles. · 罗盘针描出从 N 到 S 的磁场;在吸引和排斥之间切换,观察整个图案重组,同极之间出现中性点。
Two north poles are brought close together. They: · 两个北极被靠近放在一起。它们:
Like poles repel. Only different poles (N and S) attract. · 同极排斥。只有不同的磁极(N 和 S)吸引。
Which of these is a magnetic material (attracted by a magnet)? · 这些中哪个是一种磁性材料(被一块磁铁吸引)?
Iron (also steel, cobalt, nickel) is magnetic. Copper, plastic and wood are not. · 铁(还有钢、钴、镍)是磁性的。铜、塑料和木头不是。
Induced, temporary and permanent magnets 永磁体
- Put iron near a magnet and the iron becomes a magnet itself — induced magnetism 感应磁性. The near end gains the opposite pole, so they attract.
- Soft iron 软铁 magnetises easily but loses it quickly → a temporary magnet (great for electromagnet cores).
- Steel is harder to magnetise but keeps it → a permanent magnet (great for bar magnets).
The magnetic field of a bar magnet
感应、临时与永久磁铁
- 把铁放在一块磁铁附近,铁自己变成一块磁铁——感应磁性(induced magnetism)。近端获得相反的磁极,所以它们吸引。
- 软铁容易磁化但很快失去它 → 一个临时磁铁(很适合电磁铁芯)。
- 钢更难磁化但保持它 → 一个永久磁铁(很适合条形磁铁)。
一块条形磁铁的磁场
Which material is best for a permanent magnet? · 哪种材料最适合一个永久磁铁?
Steel is hard to magnetise but keeps it, so it makes a permanent magnet. Soft iron loses magnetism quickly, so it suits temporary magnets and electromagnet cores. · 钢难以磁化但保持它,所以它做一个永久磁铁。软铁很快失去磁性,所以它适合临时磁铁和电磁铁芯。
Match each magnetism idea to what it means. · 把每个磁性想法与它的含义配对。
Each item links the term to its correct meaning. · 每一项把术语与它正确的含义联系。
Magnetic fields
- A magnetic field is a region where a magnetic pole feels a force.
- We draw it with field lines 磁感线 that come out of N and go into S.
- Where the lines are close together, the field is strong.
- Show the pattern with iron filings or a small plotting compass (the needle points along the field).
磁场
- 一个磁场(magnetic field)是一个磁极感受到力的区域。
- 我们用场线(field lines)画它,它们从 N 出来并进入 S。
- 场线靠在一起的地方,场强。
- 用铁屑或一个小的标绘指南针显示这个图案(针沿场指向)。
Magnetic field lines around a bar magnet point: · 一块条形磁铁周围的磁场线指向:
By convention, field lines come out of N and go into S; the closer together they are, the stronger the field. · 按惯例,场线从 N 出来并进入 S;它们越靠近,场越强。
Where the field lines are closer together, the magnetic field is stronger. · 场线更靠近的地方,磁场更强。
Closely spaced field lines mean a strong field — that is why the field is strongest near the poles. · 紧密间隔的场线意味着一个强场——这就是为什么场在磁极附近最强。
Uses of magnets
- Permanent magnets: fridge catches, compass needles, loudspeakers.
- Electromagnets 电磁铁 (magnetic only while a current flows): scrap-yard cranes, electric bells, relays.
- An electromagnet's big advantage: you can switch it on and off and make it stronger — a permanent magnet cannot.
Like poles repel; unlike poles attract
磁铁的用途
- 永久磁铁:冰箱门扣、指南针针、扬声器。
- 电磁铁(electromagnets,只在电流流动时有磁性):废料场起重机、电铃、继电器。
- 一个电磁铁的大优势:你能把它开和关并使它更强——一个永久磁铁不能。
What can an electromagnet do that a permanent magnet cannot? · 一个电磁铁能做什么一个永久磁铁不能做的?
An electromagnet is magnetic only while a current flows, so it can be switched on/off and made stronger by increasing the current or turns. · 一个电磁铁只在电流流动时有磁性,所以它能被开/关并通过增加电流或匝数被做得更强。
You've got it
- like poles repel, unlike poles attract; magnetic materials = iron, steel, cobalt, nickel
- soft iron = temporary magnet; steel = permanent magnet
- field lines go out of N, into S; closer lines = stronger field
- electromagnets can be switched on/off and made stronger
你掌握了
- 同极排斥,异极吸引;磁性材料 = 铁、钢、钴、镍
- 软铁 = 临时磁铁;钢 = 永久磁铁
- 场线从 N 出来,进入 S;更靠近的线 = 更强的场
- 电磁铁能被开/关并被做得更强