Bio 11 - Microscopes

Microscope

An instrument that produces an enlarged image of an object.

Magnification

The increase in an object’s apparent size.

Resolution / Resolving power

The power of a microscope to clearly show detail and distinguish two objects as being separate.

Compound Light Microscope

A microscope that uses two sets of lenses. A light source is used to illuminate the specimen. Light passes through the specimen and through the objective lens positioned directly above the specimen. The resolving power of this microscope is limited by the physical properties of light

Electron Microscope

A microscope that uses a focused beam of electrons to see the specimen. They have much better magnification and resolution than light microscope and can therefore be used to see much smaller specimens.

Transmission Electron Microscope (TEM)

A microscope which the image is produced by a beam of electrons passing through a very thin slice of specimen (specimen must be frozen and sliced). The image appears on a screen and is a flat, 2D image. Used to see internal structures not functions or processes.

Scanning Electron Microscopes (SEM)

A microscope which the image is produced by a beam of electrons which scans the surface of the sample. As electrons bounce off the specimen they form a 3-D image of the outer surface of the sample.

Eyepiece / Ocular

A part of a microscope used to view a specimen and magnify x10.

Body Tube

A part of a microscope which serves as the connecting piece.

Revolving Nosepiece

A part of a microscope which allows the user to change magnification power.

Objective lens

A part of the microscope used to magnify the image (x4, x10, x100)

Stage clips

A part of a microscope which holds the slide in place.

Diaphragm

A part of a microscope used to control the amount of light passing through a specimen.

Light Source

A part of a microscope that is needed to illuminate a specimen.

Arm

A part of a microscope which is used as support and is held when moving the microscope.

Stage

A part of a microscope which serves as a platform to support a specimen.

Coarse Adjustment

A part of a microscope used to bring a specimen into view.

Fine Adjustment

A part of a microscope used to sharpen and clarify the image.

Base

A part of a microscope which is the support for the entire structure.