Magnifiers
Magnifiers are instruments that allow humans to see microscopic-sized objects through lenses that focus and refract light. Most cells are microscopic (10 – 100 μm long or 0.01 - 0.1 mm); therefore, magnifiers are needed to view cellular details.
Light Magnifiers
Hand Lens or Loupe
Handy, portable magnifier for viewing objects in nature at a slightly increased magnification
Hand lenses give a three-dimensional view of objects
Most provide a magnification 2x-10x, although some are 20x or 30x
The higher the magnification, the more steady your had needs to be!
Image through the lens is not inverted; it is a direct image
Dissecting or Stereo Microscope
Desktop microscope for viewing objects with higher magnification than a hand lens, but without the preparation of a compound scope
Stereoscopes are good for viewing the microscopic details of natural objects such as buds on twigs, minerals in rocks, details on invertebrates, etc.
Stereo microscopes provide three-dimensional viewing of objects
Most of these scopes provide magnification 10x-30x, but some can be up to 200x
Magnification is achieved through two different lenses: the eyepiece (usually 10x), and the objective lenses (e.g. 1x, 3x, or 20x lenses which would result in 10x, 30x, or 200x total magnification, respectively.
These scopes need an external source of light, but the object does not need to be translucent
Image through the lens is not inverted; it is a direct image
Compound Microscope
Desktop microscope for viewing objects with higher magnification than a stereo microscope, but requires preparation of the material so that it is thin and translucent
Compound microscopes are good for viewing the microscopic, internal details of organisms, such as tissues, and cells
The compound microscope provides two-dimensional viewing, due to the narrow focal range with high magnification
Compound scopes can magnify material 40x-1,000x.
Magnification is achieved through two different lenses: the eyepiece (usually 10x), and the objective lenses (e.g. 4x, 10x, 40x, or 100x lens which would result in 40x, 100x, 400x, or 1,000x total magnification.
The 100x lens is called the "oil immersion lens", and requires a drop of immersion oil on the coverslip to achieve proper optics. The 100x lens should never be employed unless immersion oil is used
The material must be thin-sliced by a razor blade or microtome in order to make it translucent
The work of thin-slicing can be avoided by using prepared slides.
Hand-made slides should use a coverslip to flatten specimen for viewing and protect the objective lenses
The compound scope shines light up through the specimen and into the objective lenses
The image through the lens is inverted; moving specimen on the stage to the right will result in the image appearing to go left.
Above: Dissecting or stereo microscope
Above: Compound microscope
Type
Use
Magnification
2D or 3D image
Direct or Inverted
Hand lens
Portable in nature, but not steady
2-10x (sometimes 20x or 30x)
3D viewing of materials in nature
Direct Image
Stereo or Dissecting Microscope
Indoor magnifier of living material
10-30x (some can reach 200x)
3D viewing of materials
Direct Image
Compound Microscope
Indoor magnifer of prepared materials
40x-1,000X (although variable)
2D viewing of thin-sliced material
Inverted Image
Electron Magnifiers
Extremely complex magnifiers/ microscopes needed to see very small objects
Electron microscopes use electrons emitted at specimens to capture an image of the object
Scanning Electron (SEM) Microscope
Three-dimensional viewing
Magnification: 15x-200,000x
Specimen prepared, dehydrated, and gold-coated!
...although the technology is improving: nano-suit for viewing live organism in SEM
Transmission Electron (TEM) Microscope
Two-dimensional viewing
Magnification: up to 350,000x
Specimen prepared (thin-sliced)
Environmental SEM (eSEM) Microscope
Three-dimensional viewing
Magnification: 1,000x-100,000x
The specimen may be living
Scanning Tunneling (STM) Microscope
View of atoms
Magnification: 10x-500,000x
Quantum Microscope
Sub-atomic viewing
Above: Scanning electron micrograph of pollen grains
Above: Transmission electron microscope
By David J Morgan from Cambridge, UK - Tecnai 12 Electron Microscope, CC BY-SA 2.0
Additional Resources
New technique allows plants to be grown and imaged inside a microscope (EurekAlert 1Jul2014)