Microscope Parts Labeled
A labelled diagram of a compound light microscope, with every part named and what it does.
What each part of a microscope does
| Lentille oculaire | The lens you look through. It magnifies the image again, usually ×10. |
|---|---|
| Body tube | Connects the eyepiece to the objective lenses and keeps them the right distance apart. |
| Arm | Supports the body tube and connects it to the base. Carry the microscope by its arm and base. |
| Revolving nosepiece (turret) | Holds the objective lenses and rotates so you can click a different one into place. |
| Objective lenses | A set of lenses (commonly ×4, ×10, ×40, ×100) closest to the specimen, each magnifying by a different amount. |
| Stage | The flat platform the slide sits on. |
| Stage clips | Hold the slide firmly in place on the stage so it doesn’t slip while you focus. |
| Iris diaphragm | Adjusts how much light passes up through the specimen, controlling contrast and brightness. |
| Condenser | A lens below the stage that focuses the light from the illuminator onto the specimen. |
| Illuminator (light source) | A built-in lamp (or a mirror, in older microscopes) that lights the specimen from below. |
| Coarse focus knob | Moves the stage up and down quickly to find the specimen. Only use it at low power. |
| Fine focus knob | Moves the stage a tiny amount, for sharpening the image, especially at high power. |
| Base | The flat bottom that supports the whole microscope and houses the illuminator. |
How light travels through a microscope
Light starts at the illuminator at the base, passes up through the condenser (which focuses it) and the diaphragm (which controls how much gets through), then through the specimen on the stage. The objective lens magnifies this first, and the eyepiecemagnifies it again before it reaches your eye.
Focus real slides, switch objective lenses and see the total magnification calculated live in the Microscope Virtuel below.
Foire aux questions
What are the main parts of a compound light microscope?
The eyepiece, body tube, revolving nosepiece, objective lenses, stage, diaphragm, condenser, illuminator, coarse and fine focus knobs, arm and base.
What is the function of the objective lens?
The objective lenses sit closest to the specimen and provide the first stage of magnification, usually ×4, ×10, ×40 or ×100. Total magnification = eyepiece × objective.
What is the difference between the coarse and fine focus knobs?
The coarse focus moves the stage a large distance quickly, to find the specimen at low power. The fine focus moves it a tiny amount, for sharpening the image, especially at high power.
What does the diaphragm do on a microscope?
The iris diaphragm controls how much light passes up through the specimen from the illuminator, adjusting brightness and contrast.
