The microscope in cell studies · 细胞研究中的显微镜
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| microscope/ˈmaɪkrəskəʊp/ | 显微镜 | xiǎn wēi jìng |
| light microscope/laɪt ˈmaɪkrəskəʊp/ | 光学显微镜 | guāng xué xiǎn wēi jìng |
| specimen/ˈspesɪmən/ | 标本 | biāo běn |
| electron microscope/ɪˈlektrɒn ˈmaɪkrəskəʊp/ | 电子显微镜 | diàn zi xiǎn wēi jìng |
| magnification/ˌmæɡnɪfɪˈkeɪʃn/ | 放大倍数 | fàng dà bèi shù |
| resolution/ˌrezəˈluːʃn/ | 分辨率 | fēn biàn lǜ |
| stain/steɪn/ | 染色剂 | rǎn sè jì |
Seeing the invisible
- Cells are far too small to see with your eyes — you need a microscope 显微镜.
- A light microscope 光学显微镜 shines light through a thin specimen 标本; an electron microscope 电子显微镜 sees far more detail.
- Two ideas you must keep separate: magnification 放大倍数 and resolution 分辨率.
看见看不见的东西
- 细胞太小,用你的眼睛看不见——你需要 显微镜(microscope)。
- 光学显微镜(light microscope) 让光透过一个薄标本;电子显微镜(electron microscope) 看到多得多的细节。
- 两个你必须分开的概念:放大率(magnification) 和 分辨率(resolution)。
Microscope decision lab · 显微镜选择实验
Choose the right microscopy idea from what the student wants to see. · 根据学生想看的内容选择合适的显微技术概念。
Light and electron microscopes
- A light microscope shines light through a thin specimen on a slide (with a stain 染色剂 to show parts, and a cover slip on top).
- An electron microscope uses beams of electrons, which have a much shorter wavelength — so its resolution is far higher and it shows tiny structures.
- Two kinds: scanning (SEM, 3-D surface) and transmission (TEM, inside detail through a thin slice).
A light microscope shines light up through the stained specimen and lenses magnify the image
光学显微镜和电子显微镜
- 光学显微镜 让光透过 载玻片(slide) 上的一个薄 标本(specimen)(用 染色剂(stain) 显示各部分,上面盖一个 盖玻片(cover slip))。
- 电子显微镜 用 电子 束,它们有短得多的 波长(wavelength)——所以它的 分辨率 高得多,能显示微小的结构。
- 两种:扫描式(scanning)(SEM,三维表面)和 透射式(transmission)(TEM,透过一个薄切片看内部细节)。
光学显微镜让光向上透过染色的标本,透镜放大图像
Why does an electron microscope have a much higher resolution than a light microscope? · 为什么电子显微镜的分辨率远高于光学显微镜？
Shorter wavelength → higher resolution, so finer detail can be seen. · 波长越短 → 分辨率越高，因此能看到更精细的细节。
Match each feature to the right microscope. · 将每个特征与正确的显微镜匹配。
Light microscopes are simpler and can view living material; electron microscopes have far higher resolution but the specimen must be dead and in a vacuum. · 光学显微镜结构简单，可观察活体材料；电子显微镜分辨率高得多，但标本必须死亡并处于真空中。
Magnification and actual size
- The top and bottom must use the same unit. Cells are tiny: $1\ \text{mm} = 1000\ \mu\text{m}$, $1\ \mu\text{m} = 1000\ \text{nm}$.
- Worked: at $\times 5000$, a chloroplast measures $25\ \text{mm}$ → actual size $= 25 \div 5000 = 0.005\ \text{mm} = 5\ \mu\text{m}$.
Calibrating the eyepiece graticule against a stage micrometer
放大率和实际大小
- 上面和下面 必须用相同的单位。细胞很小:$1\ \text{mm} = 1000\ \mu\text{m}$,$1\ \mu\text{m} = 1000\ \text{nm}$。
- 例题:在 $\times 5000$ 下,一个叶绿体量得 $25\ \text{mm}$ → 实际大小 $= 25 \div 5000 = 0.005\ \text{mm} = 5\ \mu\text{m}$。
用载物台测微尺校准目镜测微尺
Which equation gives magnification? · 哪个公式给出了放大倍率？
Magnification = size of image ÷ actual size (no units). · 放大倍率 = 图像大小 ÷ 实际大小（无单位）。
How many micrometres (µm) are in 1 mm? · 1 mm 等于多少微米 (µm)？
1 mm = 1000 µm (and 1 µm = 1000 nm). · 1 mm = 1000 µm（且 1 µm = 1000 nm）。
At magnification ×5000, a structure measures 25 mm in the image. What is its actual size, in µm? · 在放大倍率为 ×5000 时，某结构在图像中的测量值为 25 mm。其实际大小是多少微米 (µm)？
25 mm ÷ 5000 = 0.005 mm = 5 µm. · 25 mm ÷ 5000 = 0.005 mm = 5 µm。
Resolution vs magnification
- Magnification = how many times bigger the image is.
- Resolution = the smallest distance between two points that still lets you see them as two separate points.
- Making an image bigger does not always show more detail — past a point you just get a bigger blur. Resolution sets the real limit.
With low resolution two close points blur into one; higher resolution keeps them separate
分辨率与放大率
- 放大率 = 图像放大了多少倍。
- 分辨率 = 仍能让你把两个点看成 两个 分开的点的最小距离。
- 把图像放得更大 并不 总是显示更多细节——过了一个点你只是得到一个更大的模糊。分辨率 设定真正的极限。
分辨率低时两个靠近的点模糊成一个;分辨率更高时它们保持分开
Resolution is: · 分辨率是指：
Resolution is the detail limit; magnification alone cannot show detail finer than the resolution. · 分辨率是细节极限；仅靠放大倍率无法显示超过分辨率极限的更细细节。
The smallest distance between two points that can still be seen as two separate points is the ______. · 仍能被看作两个独立点的最小距离称为 ______。
Resolution is the real detail limit; magnifying beyond it just gives a bigger blur. · 分辨率是真实的细节极限；超过此极限继续放大只会得到更大的模糊图像。
Magnifying an image more and more always reveals more and more detail. · 不断放大图像总能揭示出越来越多的细节。
No — beyond the resolution limit you just get a bigger blur. Resolution, not magnification, sets the finest detail you can see. · 不 — 超过分辨率极限后，你只会得到更大的模糊图像。决定你能看到的最细细节的是分辨率，而非放大倍率。
You've got it
- light microscope (light, lower resolution) vs electron microscope (electrons, much higher resolution)
- $\text{magnification} = \dfrac{\text{image size}}{\text{actual size}}$ — same units top and bottom ($1\ \text{mm}=1000\ \mu\text{m}$)
- resolution = smallest distance to see two points apart — it sets the real detail limit
- magnifying more doesn't add detail beyond the resolution
你掌握了
- 光学显微镜(光,较低分辨率)对 电子显微镜(电子,高得多的分辨率)
- $\text{magnification} = \dfrac{\text{image size}}{\text{actual size}}$——上下相同单位($1\ \text{mm}=1000\ \mu\text{m}$)
- 分辨率 = 把两个点看成分开的最小距离——它设定真正的细节极限
- 放大更多不会增加超过分辨率的细节