What Are The Parts To A Microscope?

Compound microscope systems

the compound microscope uses lenses and light to enlarge the image and is also called an optical or light microscope (versus an electron microscope). the simplest optical microscope is the magnifying glass and is good to about ten times (10x) magnification.

the compound microscope has two systems of lenses for greater magnification:

1. ocular eyepiece lens to look through.
2. objective lens, closest to the object.

microscopes are made up of lenses for magnification, each with its own magnification powers. depending on the type of lens, it will magnify the specimen according to its focal strength.

microscopes are generally made up of structural parts for holding and supporting the microscope and its components, and the optical parts that are used for magnification and viewing of the specimen images. modern microscopes have additional electronics and display devices.

Eyepiece, tube, arm, and base

• eyepiece lens: the lens at the top that you look through, usually 10x or 15x power.
• eyepiece lens magnifies the image of the specimen. this part is also known asocular.most school microscopes have an eyepiece with 10x magnification.
• eyepiece which contains a lens to magnify an image 10x that projected by the objective lens.
• tube: connects the eyepiece to the objective lenses.
• connects the ocular lens to the objective lenses and provides alignment to direct the light from the specimen into the viewer's eye.
• arm: supports the tube and connects it to the base.
• the arm connects the base to the nosepiece and eyepiece. it is the structural part that is also used to carry the microscope.
• connects the body tube to the base. one hand should be around this when carrying a microscope.
• base: the bottom of the microscope, used for support.
• the base is the main support of the microscope. the bottom, where all the other parts of the microscope stand.
• supports the weight of the microscope. contains the electronics and the light source.
• provides support, houses the light source, and serves as a platform on a flat surface.

Nosepiece and objective lenses

• revolving nosepiece or turret: this is the part of the microscope that holds two or more objective lenses and can be rotated to easily change power.
• nosepiece holds the objective lenses and is sometimes called a revolving turret. you choose the objective lens by rotating to the specific lens one you want to use.
• holds the objective lens and can be rotated to change the magnification.
• holds the objective lenses and allows for easy switching between them.
• objective lenses: usually you will find 3 or 4 objective lenses on a microscope. they almost always consist of 4x, 10x, 40x and 100x powers.
• most compound microscopes come with three or four objective lenses that revolve on the nosepiece. the most common objective lenses have power of 4x, 10x and 40x.
• magnify specimens, typically from 4x to 100x, for detailed observation.
• this objective lens provides the lowest magnification, 4 x
• this objective lens provides a medium magnification, or power, 10x
• this objective lens provides the highest magnification, 40x
• adjustable lens system that permits the use of a low power lens, a medium lens, or a high power lens

Magnification and objective lens details

• when coupled with a 10x (most common) eyepiece lens, total magnification is 40x (4x times 10x), 100x , 400x and 1000x.
• combined with the magnification of the eyepiece the resulting magnification is 40x, 100x and 400x magnification.
• total magnification is calculated by multiplying the power of the eyepiece by the power of the objective lens. (10x eyepiece x 40x objective = 400x total magnification)
• some more advanced microscopes have an additional objective lens with 100x power. this results in 1,000x magnification.
• ocular lens magnification x objective lens magnification
• compound magnification is calculated by multiplying the magnification of the objective lens by the magnification of the eyepiece.
• total magnification = objective magnification x eyepiece magnification
• the shortest lens is the lowest power, the longest one is the lens with the greatest power.
• lenses are color coded and if built to din standards are interchangeable between microscopes.
• many high power objective lenses are retractable (i.e. 40xr). this means that if they hit a slide, the end of the lens will push in (spring loaded) thereby protecting the lens and the slide.
• all good quality microscopes have achromatic, parcentered, parfocal lenses.

Stage and stage clips

• the stage is where the specimen is placed. this place is for observation.
• where you place the slide containing the specimen; it contains a hole that allows light to pass through the stage and onto the specimen.
• where the specimen slide is placed for observation, often with clips to secure it.
• mechanical stage, you will be able to move the slide around by turning two knobs. one moves it left and right, the other moves it up and down.
• stage clips are the supports that hold the slides in place on the stage.
• holds the slides in place on the stage for viewing.
• holds the slide in place on the stage so it doesn't move while you're viewing the specimen.

Illuminator, mirror, condenser, and diaphragm

• illuminator: a steady light source (110 volts) used in place of a mirror. if your microscope has a mirror, it is used to reflect light from an external light source up through the bottom of the stage.
• most light microscopes use a low voltage bulb which supplies light through the stage and onto to the specimen.
• mirrors are sometimes used instead of a built-in light. if your microscope has a mirror, it provides light reflected from ambient light sources like classroom lights or sunlight if outdoors.
• an electric source of illumination or a mirror used to direct light upward.
• illuminates the specimen from beneath, commonly used for transparent samples.
• condenser lens: the purpose of the condenser lens is to focus the light onto the specimen.
• the lens under the stage that focuses light from the illuminator through to the hole in the stage
• condenser lenses are most useful at the highest powers (400x and above).
• microscopes with in-stage condenser lenses render a sharper image than those with no lens (at 400x).
• diaphragm or iris: many microscopes have a rotating disk under the stage.
• this diaphragm has different sized holes and is used to vary the intensity and size of the cone of light that is projected upward into the slide.
• the diaphragm controls the amount of light passing through the slide.
• it is located below the stage and is usually controlled by a round dial.
• it contains a dial that rotates to adjust the amount of light that reaches the specimen and is passed upwards towards the eyepiece.

Focus and rack stop

• coarse focus moves the stage to provide general focus on the specimen. when bringing a specimen into focus, the course dial is the first one used.
• first knob you should use and always under low power, makes large adjustments to the focus. should never be used in high power.
• fine focus moves the stage in smaller increments to provide a clear view of the specimen. when bringing a specimen into focus, the fine focus dial is the second one used.
• the second knob you should use under higher power for exact focusing.
• adjusts the sharpness of the specimen. there are two types: coarse and fine.
• rack stop: this is an adjustment that determines how close the objective lens can get to the slide.
• it is set at the factory and keeps students from cranking the high power objective lens down into the slide and breaking things.
• you would only need to adjust this if you were using very thin slides and you weren't able to focus on the specimen at high power.

Focusing a microscope

focus your microscope: the proper way to focus a microscope is to start with the lowest power objective lens first and while looking from the side, crank the lens down as close to the specimen as possible without touching it.

now, look through the eyepiece lens and focus upward only until the image is sharp. if you can't get it in focus, repeat the process again.

once the image is sharp with the low power lens, you should be able to simply click in the next power lens and do minor adjustments with the focus knob. if your microscope has a fine focus adjustment, turning it a bit should be all that's necessary. continue with subsequent objective lenses and fine focus each time.

Compound microscope parts and other microscope parts

• compound microscopes have multiple objective lenses mounted on a rotating nosepiece, typically with magnifications ranging from 4x to 100x or higher.
• other microscopes, such as dissecting or stereo microscopes, usually have fixed magnification lenses.
• compound microscopes commonly have a pair of eyepieces that provide binocular vision.
• other microscopes may have a single eyepiece or sometimes no eyepieces at all.
• compound microscopes are designed for higher magnifications, typically used for observing microscopic details.
• other microscopes may have lower magnification capabilities, suitable for larger specimens or samples.
• compound microscopes often have built-in illumination systems, such as a substage light source, condenser, and diaphragm, to provide transmitted light through the specimen.
• other microscopes, like dissecting or fluorescence microscopes, may utilize different lighting techniques or illumination configurations.
• compound microscopes are designed to observe thin, transparent specimens placed on glass slides.
• they offer a narrow depth of field, allowing clear focus on one plane at a time.
• other microscopes, like stereo or electron microscopes, can accommodate larger specimens or samples with more depth, providing a wider depth of field.