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The eyepiece of a microscope typically has a magnification of 20x.
The eyepiece of a microscope typically has a magnification of 20x.
False
Objective lenses can provide magnification ranging from 40x to 400x.
Objective lenses can provide magnification ranging from 40x to 400x.
True
The arm of the microscope is used to hold the objective lenses in place.
The arm of the microscope is used to hold the objective lenses in place.
False
When carrying a microscope, it is advisable to use only one hand to avoid accidents.
When carrying a microscope, it is advisable to use only one hand to avoid accidents.
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Stage clips are only found on one side of the stage opening.
Stage clips are only found on one side of the stage opening.
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Microscopy allows for the visualization of samples with greater detail than the unaided eye.
Microscopy allows for the visualization of samples with greater detail than the unaided eye.
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The resolving power of the human eye is greater than that of a light microscope.
The resolving power of the human eye is greater than that of a light microscope.
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Total magnification is determined solely by the magnifying power of the eyepiece.
Total magnification is determined solely by the magnifying power of the eyepiece.
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Numerical aperture is the ratio of the diameter of the lens to its focal length.
Numerical aperture is the ratio of the diameter of the lens to its focal length.
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The working distance of a microscope increases with increasing magnification.
The working distance of a microscope increases with increasing magnification.
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Abbé equation is used to calculate the limit of resolution.
Abbé equation is used to calculate the limit of resolution.
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Electron microscopes can separate points that are 0.5 mm apart.
Electron microscopes can separate points that are 0.5 mm apart.
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The Brightfield Light Microscope is exclusively suitable for specimens that can be contrasted using dyes.
The Brightfield Light Microscope is exclusively suitable for specimens that can be contrasted using dyes.
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Magnification alone guarantees the clarity and detail of the observed image.
Magnification alone guarantees the clarity and detail of the observed image.
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A Compound Microscope typically has a single lens system for magnification.
A Compound Microscope typically has a single lens system for magnification.
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The Dark-Field Light Microscope can produce contrast in images where traditional Brightfield microscopy cannot.
The Dark-Field Light Microscope can produce contrast in images where traditional Brightfield microscopy cannot.
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Differential interference contrast (DIC) microscopy is useful for viewing specimens with high inherent contrast.
Differential interference contrast (DIC) microscopy is useful for viewing specimens with high inherent contrast.
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The magnification power of a Compound Microscope can go up to 1000x.
The magnification power of a Compound Microscope can go up to 1000x.
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The only light method used in a Compound Microscope is trans-illumination.
The only light method used in a Compound Microscope is trans-illumination.
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Fluorescence Light Microscopes rely on the interaction of UV light with the specimen to produce images.
Fluorescence Light Microscopes rely on the interaction of UV light with the specimen to produce images.
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The mechanical parts of a Compound Microscope include the eyepiece lens.
The mechanical parts of a Compound Microscope include the eyepiece lens.
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The standard power range of objective lenses in a compound microscope typically ranges from 1x to 160x.
The standard power range of objective lenses in a compound microscope typically ranges from 1x to 160x.
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The typical numerical aperture (NA) for a 40x objective lens is 0.65.
The typical numerical aperture (NA) for a 40x objective lens is 0.65.
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A standard microscope typically has four objective lenses that revolve on a nosepiece.
A standard microscope typically has four objective lenses that revolve on a nosepiece.
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The eyepiece of a microscope typically magnifies the image by 5x.
The eyepiece of a microscope typically magnifies the image by 5x.
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The eyepiece functions to magnify the image projected by the condenser lens.
The eyepiece functions to magnify the image projected by the condenser lens.
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Higher numerical aperture (NA) leads to better resolving power of a lens.
Higher numerical aperture (NA) leads to better resolving power of a lens.
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There are no additional features such as scales or pointers on eyepieces for special applications.
There are no additional features such as scales or pointers on eyepieces for special applications.
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The body tube of a microscope is responsible for adjusting the focus of the lenses.
The body tube of a microscope is responsible for adjusting the focus of the lenses.
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A light source is primarily used to provide illumination for observing the specimen.
A light source is primarily used to provide illumination for observing the specimen.
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The diaphragm regulates the temperature of the microscope stage.
The diaphragm regulates the temperature of the microscope stage.
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The coarse adjustment knob should be used for fine focusing at high power objectives.
The coarse adjustment knob should be used for fine focusing at high power objectives.
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Fine adjustment knobs are used to make large movements of the stage or objective lenses.
Fine adjustment knobs are used to make large movements of the stage or objective lenses.
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Phase contrast microscopy enhances the visibility of specimens by synchronizing light phases.
Phase contrast microscopy enhances the visibility of specimens by synchronizing light phases.
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Fluorescence microscopy is utilized to visualize specific structures within a specimen.
Fluorescence microscopy is utilized to visualize specific structures within a specimen.
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Phase contrast is the least commonly used contrasting technique in microscopy.
Phase contrast is the least commonly used contrasting technique in microscopy.
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The applications of microscopy include studying the structures of different microbial elements.
The applications of microscopy include studying the structures of different microbial elements.
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An electron microscope can magnify structures from 10 to 250,000 times greater than a light microscope.
An electron microscope can magnify structures from 10 to 250,000 times greater than a light microscope.
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Transmission electron microscopy (TEM) is primarily used to visualize the surface features of specimens.
Transmission electron microscopy (TEM) is primarily used to visualize the surface features of specimens.
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Scanning electron microscopy (SEM) requires the specimen to be prepared as thin sections.
Scanning electron microscopy (SEM) requires the specimen to be prepared as thin sections.
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Electron beams have a longer wavelength than visible light, resulting in lower resolution.
Electron beams have a longer wavelength than visible light, resulting in lower resolution.
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Heavy metal coatings are used in SEM to improve the contrast of the specimen images.
Heavy metal coatings are used in SEM to improve the contrast of the specimen images.
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OXIC acid, permanganate, uranium, and lanthanum are used to stain specimens for transmission electron microscopy.
OXIC acid, permanganate, uranium, and lanthanum are used to stain specimens for transmission electron microscopy.
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Both TEM and SEM allow for the examination of specimens without the need for any special preparations.
Both TEM and SEM allow for the examination of specimens without the need for any special preparations.
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The electron source in a scanning electron microscope is located inside an evacuated chamber.
The electron source in a scanning electron microscope is located inside an evacuated chamber.
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Study Notes
Microscopy and Micrometry
- A person is paid based on time or value
- Microscopy is the technical field using microscopes or microscope objectives to examine samples in greater detail
- Objectives include Light, Fluorescent, phase contrast, and electron microscopy
- Microscopic principle is to magnify an image that could not be resolved with the naked eye
- Magnification is the ratio of the size observed under a microscope to the actual size of the object under a naked eye
- Total magnification is the result of multiplying the objective lens and eyepiece magnification
- Maximum magnification doesn't equal maximum resolution
- Resolving power: The ability to differentiate two close points as separate
- Human eye resolving power is 0.25 mm
- Light microscope resolving power is 0.25µm
- Electron microscope resolving power is 0.5nm
- Limit of resolution is the minimum distance between two points distinguishable as separate and is calculated by the Abbé equation
- Resolving power (R.P.) = Wavelength of light in nm / (2 × Numerical aperture of objective lens)
- Numerical Aperture (NA): The ratio of the diameter of the lens to its focal length
- NA is an estimate of how much light from the sample is collected by the objective
- NA = n sin α (n = refractive index, α = angle of incident illumination)
- The higher the NA the better the resolution of a specimen is
- d = 0.5 λ/n sin θ (d = resolution, λ = wavelength of light used)
- Numerical aperture, not magnification determines resolution
- Imaging techniques include Optical Microscopy, Confocal Microscopy, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Atomic Force & Scanning Tunneling Microscopies (AFM/STM). Their respective image formation methods are: Light Rays, Coherent light source (laser), Electrons, Electrons, and Molecular Mechanical Probes, respectively.
- A microscope is a high-precision optical instrument using a lens or a combination of lenses for highly magnified images of small specimens that cannot be seen by the naked eye.
- A light source (mirrors or lamps) is used to illuminate the specimen.
- Microscopes are used to view specimens too small to be seen with the naked eye.
History
- In 1590, F.H Janssen and Z.Janssen made the first simple compound light microscope (10x to 30x)
- In 1665, Robert Hooke developed the first laboratory compound microscope
- Later scientists (Kepler and Galileo) developed advanced classroom microscopes
- In 1672, Anton Von Leeuwenhoek built a simple microscope with a magnification of 200x to 300x
- Anton Von Leeuwenhoek observed bacteria, yeast, plants, and life in a water drop in 1674
- In 1623, the term "microscope" was coined by Faber
- Electron microscopes were developed in the early 1930s, dramatically increasing magnification from about 1000x to 250,000x or more
Light Microscopy
- Visible light is used in light microscopy
- Glass lenses are used to focus light
- A significant advantage is that light microscopy can often be used on living cells
- Allows watching processes like cell migration or division
- Types of light microscopes include Brightfield, Phase Contrast, Dark-Field, and Fluorescence
Contrasting Techniques
- Differential interference contrast (DIC) introduces contrast to images of specimens with lack thereof when using a brightfield microscopy
- Brightfield microscopy: Light transmitted through the sample is absorbed by it.
Compound Microscope
- A common type of microscope with high magnification (40x to 1000x)
- Compound microscopes use multiple lenses in a line for magnification.
- Standard microscopes have objective lens and eyepiece lens.
- Objective lenses typically have 3, 4 or 5 lenses rangings from 4x to 100x (including oil immersion)
- Usually have 40x, 10x, 40x, and 100x (oil immersion) objective lenses
- The lenses revolve on a nosepiece to change the magnification
Anatomy of a Microscope
- Components include the ocular lens, diopter adjustment, nose piece, mechanical stage, condenser, illumination, brightness adjustment, base, objective lens, frame (arm), stage control, coarse adjustment, fine adjustment, and light switch.
Parts of a Compound Microscope
- Mechanical parts include base/metal stand, pillars, inclination joint, curved arm, body tube, draw tube, coarse adjustment, fine adjustment, stage, mechanical stage (slide mover), revolving nosepiece
- Optical parts include light source, diaphragm, condenser, objectives, and eyepiece
Objective Lenses
- Critical components of a compound microscope
- Vary in power from 1x to 160x
- Standard microscopes usually have 4x, 10x, 40x, and 100x (oil immersion) objectives
Numerical Aperture
- Measurement of a microscope objective's ability to gather light
- Higher NA leads to better resolution
- Typical NA values for objective lenses include 4x (0.10), 10x (0.25), 40x (0.65), and 100x (1.25).
Ocular Lens (Eye Piece)
- Consists of a series of lenses that magnify the image projected by the objective lens.
- Common magnification is 10x.
- Includes features like scales, pointers, crosshairs, and markers for special applications
Nosepiece
- Holds the objective lenses
- Rotates to allow for changing magnifications
Arm
- Supports the upper parts of the microscope and is used to carry the microscope (using two hands)
Base
- Supports the entire microscope, used to carry (with two hands)
Stage
- Supports the microscope slide
Stage Clip
- Holds the slide in place
- Typically, a pair for holding specimens
Light Source
- Provides illumination for viewing specimens
- Can be a mirror or an illuminator
Diaphragm
- Controls the amount of light entering the lenses
- Adjustable for different thicknesses of specimens for optimal illumination
Coarse Adjustment Knob
- Used to rapidly adjust focus, mainly for low-power objectives (4x)
Fine Adjustment Knob
- Used for precise focusing, usually for medium and high-power objectives (10x and 40x).
Phase Contrast
- A technique for enhancing contrast in specimens with low inherent contrast.
- Used widely in tissue culture and timelapse microscopy
Applications of Phase Contrast
- Determining morphologies of living cells (plant and animal)
- Studying microbial motility and structures
- Detecting microbial elements like bacterial endospores
Fluorescence
- Uses fluorescent dyes to highlight specific structures
- Visualization of bacterial agents like Mycobacterium tuberculosis and other agents
- Identify antibodies against pathogens and microorganisms
- Differentiation between dead and live bacteria
- Used in identifying and observing microorganisms labeled with fluorophores in ecological studies
Darkfield
- Illuminating rays of light are directed through the sample from the side
- Light scattered by specimens is enhanced
- Visualization of unstained/colourless specimens, like diatoms
Electron Microscopy (general)
- Uses electrons instead of visible light
- Electromagnets act as lenses
- Entire system operates in a vacuum
- Includes transmission and scanning electron microscopy
Transmission electron microscopy (TEM)
- Used for viewing interior structures of specimens
- Thin sections are needed, as well as negative stains, for specimen preparation.
Scanning electron microscopy (SEM)
- Visualizes external features of organisms or cells
- Coating of specimens with heavy metals improves contrast.
Electron Micrographs
- Typically, black and white images
- Often have false color added to enhance visual appeal.
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Description
Test your knowledge on essential microscopy concepts including magnification, resolving power, and the differences between light and electron microscopes. This quiz will cover various components and functions of microscopes to enhance your understanding of microscopy techniques.
