What is Microscope: Definition and 280 Discussions

A microscope (from the Ancient Greek: μικρός, mikrós, "small" and σκοπεῖν, skopeîn, "to look" or "see") is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisible to the eye unless aided by a microscope.
There are many types of microscopes, and they may be grouped in different ways. One way is to describe the method an instrument uses to interact with a sample and produce images, either by sending a beam of light or electrons through a sample in its optical path, by detecting photon emissions from a sample, or by scanning across and a short distance from the surface of a sample using a probe. The most common microscope (and the first to be invented) is the optical microscope, which uses lenses to refract visible light that passed through a thinly sectioned sample to produce an observable image. Other major types of microscopes are the fluorescence microscope, electron microscope (both the transmission electron microscope and the scanning electron microscope) and various types of scanning probe microscopes.

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  1. D

    Compound Microscope Homework: Angular Magnification & Object Distance

    Homework Statement A microscope has an eyepiece that gives an angular magnification of 5.25 cm for a final image at infinity and an objective lens of focal length 1.45 cm. The tube length is 16.1 cm. a - What is the transverse magnification due to the objective lens alone? b - what is the...
  2. S

    Macroscopic vs. microscopic continuity equation

    Homework Statement Derive a microscopic version of the continuity equation given \rho(\vec{r},t) = \sum_{i=1}^N \delta(\vec{r}-\vec{q}_i(t)) and \rho is dynamic variablesHomework Equations I wonder if someone can point out the difference (in general) between the macroscopic and microscopic...
  3. StevieTNZ

    Reversibility on Microscopic Level

    Hi there, Quick question - I know the processes in the microscopic realm are reversible. However, in 'Quantum physics: illusion or reality', Rae says that this is true except for one or two subatomic particle processes. Which particles are these, and why aren't they reversible?
  4. A

    Conceptual question on wave-particle duality (electron microscope)

    according to wave particle duality particles such as electrons exhibit wave like properties. and the wavelngth is given by lambda=h/p, so increase momentum and get shorter lambda. This property is utilised in the electron microscope to get very short wavelengths and so have very high...
  5. A

    Conceptual question on wave-particle duality (electron microscope)

    according to wave particle duality particles such as electrons exhibit wave like properties. and the wavelngth is given by lambda=h/p, so increase momentum and get shorter lambda. This property is utilised in the electron microscope to get very short wavelengths and so have very high...
  6. L

    Scanning Tunneling Microscope

    Homework Statement A scanning tunneling microscope (STM) can precisely determine the depths of surface features because the current through its tip is very sensitive to differences in the width of the gap between the tip and the sample surface. Assume that in this direction the electron wave...
  7. P

    Scanning Tunneling Microscope Question (introductory modern physics)

    Homework Statement A scanning tunneling microscope (STM) can precisely determine the depths of surface features because the current through its tip is very sensitive to differences in the width of the gap between the tip and the sample surface. Assume that in this direction the electron wave...
  8. K

    Scanning Electron Microscope Scanning Coils Kapton

    Hello, I am working on researching new ways to insulate some scanning coils on the SEM I work on. Currently we use Kapton to insulate the wires but it becomes brittle and wears over time easily. I am looking for alternatives to using Kapton for the scanning coils. Any ideas and suggestions...
  9. R

    Can we see the moon through a microscope?

    I was wondering if there was a way to build something to see the surface of the moon easily like our satellites can zoom in on us... Is it possible to take a mirror and put it under a microscope that has say 10,000x magnification. Then take a second mirror and reflect the moon onto the mirror...
  10. A

    Resolving Power of a microscope

    I don't know where to put this one. The resolving power of a microscope(simple) is defined on the basis of diffraction effects.I have read that and as far as my understanding goes it is 2μsinβ/(1.22λ). This was assuming circular aperture for the lens. [Here 2β is the angle subtended by the...
  11. I

    Microscopic electric fields in a conductor

    Hello I have just read first five chapters from Feynman's "Lectures on Physics Vol. 2" on electromagnetism and couldn't find satisfactory answer to my question, so I am posting this question. Its claimed that electric field inside a "perfect conductor" (something with unlimited...
  12. 1

    Quantum Physics: Electron Microscope

    Quantum Physics: Electron Microscope Homework Statement Consider electrons in the accelerating voltage of 15 kV used in an electron microscope with a 'lens' diameter D = 0.5 cm and focal length f= 50 cm. a) We require that the resolution is a tenth of the size of the object we want to...
  13. L

    What is the truth about Robert Hooke's microscope discoveries?

    Homework Statement I've been looking over the internet about Robert Hooke but there seems to be conflicting information about his work. Now I know that he was the first to discover the cell using a microscope and Anton van Leeuwenhoek was the first to discover microbes using a much stronger...
  14. S

    Choosing the right microscope

    I've read a lot of online articles about buying a microscope, but I guess I'm just looking for some advice. I plan on buying a compound microscope sometime in the near future for hobbyist use. It would be sheerly for my own entertainment. I've been looking at used microscopes on ebay, and...
  15. C

    The difference between microscopic and macroscopic cross sections.

    Hello there folks. So I'm doing some homework, and one of the questions asks for a comparison of the microscopic absorption cross sections of B, Cd, Gd, and Hf with the fission cross section of U-235. I've found the fission cross section in my trusty 17th edition of Nuclides and Isotopes, but...
  16. Z

    How is the microscopic crystal structure visible?

    I just noticed that it's often taken for granted that a macroscopic crystal has a similar geometric structure as in the atomic scale. What is the physical explanation for this (assuming it is true)?
  17. R

    Color of Microscopic Particles?

    Do molecules, atoms, and subatomic particles have color? If so, what? Is it even possible to determine if they do or not (Can electron microscopes see electrons?)? Is color even relevant at lengths this small? I would elaborate more but these questions are fairly straightforward.
  18. J

    Microscopic properties of electrical resistance

    I have recently been learning about the microscope properties which dictates electrical resistance. The main equation (resistivity) in my textbook is: \rho = 2m/qN\tau where \tau is the time between collisions of electrons with the atoms, q is the charge of the electron, N is the number of...
  19. R

    Microscopic description of glass-light interaction

    Hi all, could you suggest me references that can help me in the following calculation? I would like to see how to describe microscopically the interaction of light (or in general of an external field) with a disordered system such as glass ( I can find literature only for materials modeled...
  20. B

    Need to Refocus Projected Image Through Microscope Objective

    Greetings- As will become abundantly clear from this post, I know very little about optics, so any and all help will be appreciated. I am a visual neuroscientist and I am attempting to project a visual stimulus through a camera port on a microscope, off a mirror, through the microscope...
  21. U

    Optical Transfer Function of a microscope

    Hi all, I have a question about the "missing cone" problem in wide-field microscopy. The Fourier equivalent of the PSF is the OTF. The OTF has a toroidal (doughnut) shape. I'm a little confused by how to interpret the OTF support in the Z dimension. In 2D and considering lateral...
  22. C

    Relativistic Wavelength of Electron in Transmission Electron Microscop

    [I could not fit the last "e" into the title] Hi! I am writing a report on TEM, and was asked to consider the effect of accelerating voltage on the resolution. Since resolution in the light microscope is limited by the wavelength of visible light, we obtain much higher resolutions in a TEM...
  23. B

    Hooke's Law on a microscopic level

    Hooke's law states that the force required to stretch/compress a spring is proportional to the distance stretched. Meanwhile, electromagnetic interactions between particles obey an inverse-square law with respect to distance. So, if as a spring is stretched, it's composite particles get farther...
  24. N

    Movement of bacterium in the microscope

    Homework Statement A biologist looking through a microscope sees a bacterium at r1→ = 2.2i + 3.7j -1.2kμm. After 6.2s, it's at r2→ = 4.6i + 1.9kμm. a)What is it's average velocity b) What is its average speedThe Attempt at a Solutiona) v→= Δr/Δt v = (r2-r1)/6.2 = (2.4i - 3.7j + 3.1k)μm/6.2s =...
  25. V

    Images produced by a simple two lens microscope?

    Homework Statement The image formed by a simple two lens microscope is (a) real and inverted. (b) real and upright. (c) virtual and upright. (d) virtual and inverted. (e) none of these. Homework Equations N/A The Attempt at a Solution I was confused on how to understand how...
  26. WCOLtd

    Looking at Mankind Through a Giant's Microscope

    This is one of my favorite thought experiments. Imagine for a moment, you are a giant looking down at earth, and seeing it as if a person observing organisms from a microscope. imagine the microscope isn't good enough to see people but resolute to make out which look to be grey patches...
  27. P

    Geometric optics on microscopes

    An infinity corrected microscope objective has a magnification of 100× for a tube lens with focal length 180 mm. The numerical aperture of the objective is 0.90. Calculate the the diffraction limited spatial resolution if the objective is used with red light (660 nm). (Ans.: f=1.8 mm; d=447...
  28. B

    How can I improve my back-scattered images with a scanning electron microscope?

    Hi, I am working with a scanning electron microscope with the SED and it works fine. I have tried on several occasions to use the BSED without any success. All I get is a very faint dark image. Would you be able to give me some advice as to where I am going wrong? Thanks in advance
  29. B

    Understanding microscope resolution limit

    My question involves understanding why there is a limit to resolution of a microscope. I have a hard time putting what i think is happening into words. My attempt: When light of some wavelength strikes an object on the scale of that same wavelength it gets reflected. Since the details on...
  30. U

    Microscope condensers and resolution kohler illumination

    Hi all, I have a couple of questions about the process of kohler illumination (optimised condenser alignment) in brightfield microscopy and how this affects the final resolution attained. Resolution concerns the minimum detectable distance between two objects and the closer to structures...
  31. wasteofo2

    Microscopic Alien life found on British Balloon?

    http://www.dailymail.co.uk/sciencetech/article-2416761/Scientists-claim-evidence-ALIEN-LIFE-Balloon-sent-edge-atmosphere-picks-organisms-come-space.html "British scientists believe they have found evidence alien life after sending a balloon to the edge of space. The team of scientists sent...
  32. U

    Elementary lens system, microscope with negative ocular

    Homework Statement Surgeons often use a type of "binocular microscope" [that's a word by word translation]. It consists of a 50mm lens close to the patient and a -15mm right in front of the doctor's eye. The distance between the patient and the 50 mm lens is 400mm and the negative lens is...
  33. E

    Simple Microscopes: Find Focal Length & Magnifying Power

    I performed a simple experiment to find the focal length of a magnifying glass. Taking a white sheet of paper as a screen and a building as object at infinity, i got a clear image at 12.5 cm, which is approximately the focal length of the lens. Plugging this into the formula for magnifying power...
  34. D

    Phase-plane dynamics of an atomic force microscope cantilever.

    Hello, A sinusoidally driven and undisturbed cantilever of an atomic force microscope (AFM) oscillates ideally in a sinusoidal fashion but the motion of the cantilever (time-domain trajectory) can become more complicated when it is disturbed by the inter-atomic forces as the cantilever taps...
  35. H

    How do i demonstrate thin film interference with microscope slides?

    How do i demonstrate thin film interference with microscope slides? Textbook questions all mention that you will get parallel fringes when you put a hair between two microscope slides. However, i have tried doing so, but don't get the parallel fringes. I used a red laser pointer, and a...
  36. T

    Why do objects reflect light (microscopic point of view)

    Hi, I can explain why objects reflect, absorb or transmit light by referring to the objects' refractive index (differnece of the refractive index of two media). I'd like to know if there is a microscopic point of vue that can explain why objects reflect light? For example * Light is...
  37. rkatcosmos

    What Can You See When You Look at a Mirror Under a Microscope?

    If a piece of mirror is observed under a high magnification optical microscope, then what would one see??
  38. D

    What are the tiny, fast-moving life forms in my yard and mulch pile?

    A while back I managed to get (2) very nice surplus Nikon microscopes from UC Davis (CA). Since then I have taken several grass root and compost samples from my yard and mulch pile and cultured them in glass bottles with purified drinking water. I wind up with all kinds of life forms that...
  39. T

    Can I Safely Grow Microorganism Cultures for Microscope Observation at Home?

    Hi, so I have a little background in biology. I took AP bio in HS and got a 5 and really enjoyed it along the way. I got a microscope for my own amusement and also to maybe spark an interest in my little brother. What I'm having trouble with is finding good densities of moving microorganisms...
  40. C

    Compound microscope focal length

    Homework Statement The barrel of a compound microscope is 15 cm in length (distance between lenses). The specimen will be mounted 1.0 cm from the objective, and the eyepiece has a 5.0-cm focal length. Determine the focal length of the objective lens. Known: f2=5cm, L=15cm, do1=1cm...
  41. E

    Diffraction Limit Sample for Microscope

    Hi all, So, I'm trying to "hit" the diffraction limit (i.e. view Rayleigh criterion, or Abbe or Sparrow criterion) with my light microscope . Bought the scope off amazon..it's a typical AmScope that has 2000x magnification limit... But the trouble is I can't find a good sample of two spots...
  42. M

    Find the resolving power of a microscope in terms of its diameter

    Find the resolving power of a microscope lens in terms of its diameter Homework Statement In this problem, we will find the ultimate resolving power of a microscope. First of all, in order to obtain a large magnification, we want an objective lens with a very short focal length. Second, in...
  43. S

    Is time quantum at the microscopic level?

    Time has always baffled me. I have two questions for you. 1. What's the genesis of time? 2. Is time quantum at the microscopic level? Thank you.
  44. Z

    Scanning Tunnelling Microscope

    Homework Statement The tip of a scanning tunnelling microscope is placed 1.0 nm away from a conducting surface and a potential of dV = 0.03 V is applied to the surface relative to the tip. When the tip is moved laterally to a new position on the surface the tunnelling current increases by...
  45. R

    Functioning of a compound microscope

    "The diameter of the eyepiece is greater than that of the objective. This helps to collect more light and gives a brighter image" I thought that increasing the aperture of a lens doesn't increase the brightness of a virtual image. Yes, it will increase the brightness of a real image caught on...
  46. R

    Using microscope for OPAQUE samples

    I have an optical microscope and some opaque samples that I want to examine the surface of. I drew up a picture of how the microscope is arranged (attached). There is a series of lenses on a rotating drum that are located underneath the stage where glass slides are placed. The lenses usually...
  47. T

    How do I calculate the illuminated spot on specimen in optical microscope?

    Hi, When we use an optical microscope, how do we roughly calculate the illuminated spot size on the sample ? Also what is the light power on that spot? And what if I change to fluorescence microscope(epi illumination)? Cause the illuminating light go through the rear side of objective to...
  48. J

    X-ray and electron microscope diffraction patterns

    Hey, I'm having trouble finding a clear answer anywhere. When you have a x-ray diffraction pattern, do the dark spots correspond to the positions of atoms? Or do they represent the position of atoms in reciprocal space or something like that? It would seem natural to assume that the peaks are...
  49. Z

    Exponental Tunnelling Factor (Electron Microscope)

    I'm reading a little bit about electron microscopes. It states, "the exponential tunnelling factor is proportional to the square root of the mass. So, the lower mass means lower exponential decay of the wavefunction". Would anyone be able to let me know what this exponential tunnelling...
  50. schrodingerscat11

    Getting the concentration from Scanning Electron Microscope

    Greetings! I am doing particle analysis using a JEOL 5310 Scanning Electron Microscope (SEM). Typically, people here in the lab report the results in % Element or % Atomic. I think the former refers to the weight percentage of an element and the latter to the stoichiometric ratio of...
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