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. N

    Interference in thin microscope films

    Homework Statement "One microscope slide is placed on top of another with their left edges in contact and a human hair under the right edge of the upper slide. As a result, a wedge of air exists between the slides. An interference pattern results when monochromatic light is incident on the...
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    Microscope field of view & depth of field/focus (confocal microscopy)

    Hi I am trying to run a FRAP (fluorescence recovery after photo-bleaching) experiment but I am struggling a little bit. For those not exposed to the technique it involves, for example, bleaching a spot in a specimen that is fluorescing rendering that spot dark in contrast. I have two separate...
  3. P

    The Magnification of a Microscope Given Distances and Focal Lengths

    Alright, I was hoping that someone could help me out with this... The problem is: "The distance between the eyepiece and the objective lens in a certain compound microscope is 21.0 cm. The focal length of the eyepiece is 2.60 cm, and that of the objective is 0.400 cm. What is the overall...
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    What Does the Negative Sign Indicate in the Mo Formula on HyperPhysics?

    Homework Statement At this site http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/micros.html , what does the negative sign indicate in the Mo formula? Homework Equations On website The Attempt at a Solution My guess is that either L or Fo are negative, but a negative magnification...
  5. A

    Understanding the Negative Sign in Microscope Mo Equation | HyperPhysics

    I came across http://hyperphysics.phy-astr.gsu.edu/hbase/geopt/micros.html Any idea what the negative sign indicates in the mo equation?
  6. S

    Can You Make a Telescope Using Water Drops?

    Is it posible to make a telescope using water drops? (water drops are to be on transparent plastic or glass, set at desired distance; convex lense is a free drop, concave is a water drop in a ring (because of surface tension))
  7. G

    Calculating the Angle Subtended by Red Blood Cells Under a Microscope

    A typical red blood cell subtends an angle of only 1.90E-5 rad when viewed at a person's near-point distance of 25.0 cm. Suppose a red blood cell is examined with a compound microscope in which the objective and eyepiece are separated by a distance of 12.5 cm. Given that the focal length of the...
  8. T

    Looking for a great microscope below 1um, .

    Hello everyon, Sorry if this is the wrong sub forum but I thought it would work. I am trying to photograph carbon nanofibers with a microscope (I don't need it to be too fancy). I am in the range of 200-600 nm and I cannot measure them too well with the 40x lens on the University's...
  9. L

    Optical Microscope Homework: Calculating Magnification & Viewing Distance

    Homework Statement Hi. I'm required to calculate the magnification of a microscope with the variables given. I have calculated this, but was just wondering if the best viewing distance is bigger than the length of the microscope, would this have any effect? Homework Equations N/A The Attempt...
  10. A

    Total magnification of microscope

    I have a small question. I am using coumpound microscope with video attaced and I got using 40X times objective and 10X eyepiece that my magnification on video screen is 1000 times.I know that between eyepeace and video system where is a beam splitter and between beam splitter and video screen...
  11. A

    How Can You Measure Real Experimental Magnification in a Microscope?

    Homework Statement I had a lab. where ´the compound microscope was used.The microscope was equipped with 4X,10X,20X,40X,100X objectives and oculal 10X.First I had to calibrate my microscope using 1mm long calibrated graticule (divided in 100 grid lines-distance between two lines is 10...
  12. N

    Rational approach for specifying a Microscope

    Has anyone worked out a functional Parametric chart that enables one to choose a appropriate Microscope (exclude Scanning electron MicroScopes(MS)) amongst the multitude of choices for a modern academic micro-biological & research lab, hence formulated a general guideline? The MS should feature...
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    Limitation to resolution of microscope

    describe two things that limit the resoultion of light microscope?
  14. A

    Need light with less heat for microscope

    I'm using a confocal optical (reflection) microscope to look at cryo (cold) specimens (held at below -20C). The objective is 1.4 cm from my sample, and separated from it by a couple of layers of glass, BUT NONETHELESS the light is melting away the ice in my samples, damaging them within 5-10...
  15. L

    Calculating Specimen Size Using Microscope Magnification | Homework Help

    Homework Statement If the field diameter on 40X is 1600 µm, and a specimen takes up one quarter of the field, how big is the specimen in real life?Homework Equations Magnification of image= Image size/ Real size of objectThe Attempt at a Solution I'm not sure but in the formula, would be put...
  16. H

    Can universal microscopes view viruses without killing them?

    I was reading about Dr Royal Rife and his universal microscope there and the author of the article claimed that universal microscopes can be used to view viruses without killing them like electron microscopes do. Is this true? Also are these universal microscopes still in use today? Before now...
  17. A

    Microscope magnification question

    Homework Statement A compound microscope has a length of 25 cm. The objective lens has a linear magnification of -20cm, and the eyepiece has an apparent magnification of 10, what are their focal lengths (fe and fo)? How close to the objective lens should the object be placed for viewing the...
  18. U

    Biology - Calculating Resolving Power of Microscope?

    Biology -- Calculating Resolving Power of Microscope?? Homework Statement The question is this: Resolving power is a function of the wavelength of light used and the numerical aperature of the objective lens. Given that RP= wavelength / (2 x NA), calculate the resolving power of the...
  19. H

    How Does Heisenberg's Microscope Observe Electrons Outside the Aperture Angle?

    I have a question about Heisenbegs gamma-ray microscope and observed electrons. In this example is it so that we observe the electron only in limited angle of aperture θ. So the remaining electrons which scatter the gamma ray outside the aperture θ are not being observed at all? What...
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    A single pentacene molecule observed through an atomic force microscope

    awesome! i guess it won't be long now before people will be able to do this with their iPhones: http://www.dailymail.co.uk/sciencetech/article-1209726/Single-molecule-million-times-smaller-grain-sand-pictured-time.html
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    Explaining Microscope Functionality using Funsci's Lens Layout | Need Help

    I have made a micrscope for a class, and now i have to explain how it works. I followed the lens layout from this website http://www.funsci.com/fun3_en/ucomp1/ucomp1.htm, and I don't understand why I have the plano-convex lenses oriented the way they are. Basically in the objective I have two...
  22. K

    Why is the Rayleigh Criterion not a definitive resolution limit for microscopes?

    From Rayleigh criterion, the resolution of microscope is given by \sin\theta = 1.22\frac{\lambda}{D} where D is the separation b/w two objects. Suppose D is constant, image and object distances are fixed, if we want to increase the resolution, we should increase the angle (theta) right? So...
  23. C

    Digital microscope: A question

    I'm hoping this is the best forum for this... I'm considering buying a digital microscope for my lab. Specifically I'm looking at this model: http://www.sunrisedino.com/index.php?main_page=product_info&cPath=9&products_id=126 The reason I'm looking at this is that it's both portable, small...
  24. K

    How Do You Calculate the Focal Length of a Microscope's Eyepiece?

    Homework Statement The near point of a naked eye is 25 cm. When placed at the near point and viewed by the naked eye, a tiny object would have an angular size of 5.2X10-5 rad. When viewed through a compound microscope, however, it has an angular size of -9.20X10-3 rad. (The minus sign...
  25. K

    Highest Resolution Modern Microscope - Info & Resources

    Hi there, Anyone know what is highest resolution of modern microscpe? And what kind of this microscope is? Where can I get the related information?
  26. M

    Microscope Theory - Alternatives to the use of light?

    Microscope Theory - Alternatives to the use of visible light? Hey guys. I've been googling for ages but I've had no luck with this so I thought you guys could help me figure this out. Why can't UV light or gamma rays be used to observe objects in microscopy? I know the main idea behind the...
  27. J

    Quantum Tunneling in a Scanning Tunneling Microscope

    Hi! I have a physics presentation tomorrow where I have to explain how a scanning tunneling microscope works. I also have to explain what quantum tunneling is and how it is used in a scanning tunneling microscope. I've done some research on the internet and I think I have a basic grasp of...
  28. S

    Microscope: Aperture, Light Source Impact on Image Contrast/Depth/Light

    How will changing the aperture of the condenser of a microscope and the power of the light source change the image when it comes to contrast, depth of field and amount of light that reaches the camera?
  29. T

    Calculating Objective Lens Focal Length for Compound Microscope

    Homework Statement The barrel of a compound microscope is 14.8 cm in length. The specimen will be mounted 1.03 cm from the objective, and the eyepiece has a 4.92 cm focal length. Determine the focal length of the objective lens Homework Equations (1/Do)+(1/Di)= (1/f) The Attempt...
  30. R

    Help Microscope gets too hot

    I am trying to get a close look at magnetic nanoparticles under a relatively strong microscope (600 times plus). I am trying to observe their behaviour when an alternating magnetic field is applied. The problem is the alternating magnetic field heats up all metal in its surroundings...
  31. J

    I want to buy a microscope Meiji MT 5000

    I want to buy a microscope, and I want a really good one, and I want to do both dark field and phase contrast. I am looking at the Meiji MT 5000. I was wondering, what must be done to change from phase contrast to darkfield mode? Do I just need to change the objectives...
  32. M

    Monochromatic Light Through Two Microscope Slides

    Homework Statement Monochromatic light of wavelength 500nm shines on a pair of identical glass microscope slides that form a very narrow wedge, as shown in the diagram. The top surface of the upper slide and the bottom surface of the lower slide have special coatings on them so that they do...
  33. D

    Experimental error for the travelling microscope

    Whats the scale reading error for a traveling microscope Hi At school we done an experiment to determine the refractive index of a liquid using real and apparent depth. We used a traveling microscope a glass beaker and a coin. One question we got was what was the scale reading error...
  34. L

    Angular Magnification of Microscope

    Homework Statement Hey, I'm having trouble with this question on microscopes. A microscope is made up of an objective of power +100D and an eyepiece of power +50D, the two lenses being separated by 18cm. How far in front of the objective must an object be placed if the image of the object...
  35. S

    Can We See Photons With Naked Eye?

    that could be used with our naked eye and we could see photons, would they colllapse to a particle?
  36. N

    Microscope to view sample in focus with a completely relaxed eye

    Homework Statement A microscope has a converging lens (eyepiece) with focal length of 2.50 cm mounted on one end of a tube of adjustable length. At the other end is another converging lens (objective) with a focal length of 1.00 cm. When you place the sample 1.30 cm from the objective, what...
  37. C

    Microscope Questions - Moving Specimens & Light Intensity

    I need guidance on these questions, on microscopes Homework Statement In what direction will you move a centrally positioned specimen on a slide in order to view the top right hand corner of the specimen 2. The attempt at a solution is it to right then up ? someone please confirm this...
  38. K

    What's wrong with Heisenberg's microscope?

    One way in which Heisenberg originally argued for the uncertainty principle is by using an imaginary microscope as a measuring device [2] he imagines an experimenter trying to measure the position and momentum of an electron by shooting a photon at it. If the photon has a short wavelength, and...
  39. C

    Look at Ice Through a Microscope - Charlie

    hi every1 what do you see if you look at ice through a standard microscope? is the structure too small to be seen? thanks charlie
  40. B

    Simple Microscope Problem that I have been STUCK on

    Simple Microscope Problem that I have been STUCK on! Homework Statement How far from a lens of focal length 50 mm must the object be placed if it is to form a virtual image magnified in size by a factor of 3? Homework Equations The Attempt at a Solution I thought I could us the...
  41. N

    Recommend me a good microscope?

    I was wondering if someone would recommend me a good microscope? I am majoring in Molecular Biology, and would like a decent optical microscope for viewing cells and bacteria. What is a good and reliable model that is not too expensive? I see a lot of microscopes on ebay for around $250-$350...
  42. V

    Angular magnification of a microscope

    Homework Statement The image formed by a microscope objective with a focal length of 5.00\;{\rm mm} is 160\;{\rm mm} from its second focal point. The eyepiece has a focal length of 26.0\;{\rm mm}. What is the angular magnification of the microscope? Homework Equations The...
  43. E

    Minimum wavelength of light and electrons? Microscope related.

    I noticed that websites usually say that the maximum effective magnification of a light microscope is 2000x, so electron microscopes are used for greater resolution due to their shorter wavelength, but don't photons in the gamma ray range have an even shorter wavelength, allowing them to see...
  44. U

    Exploring Smoke Particles in a Glass Tube with a Microscope

    Homework Statement Using a microscope, smoke particles can be seen moving inside a glass tube. They appear as tiny spots of light that move in various directions. The air molecules inside the glass tube cannot be seen with the aid of the microscope. a) State why a microscope is needed to...
  45. E

    Scanning Tunnelling Microscope (STM)

    ''The Scanning Tunnelling Microscope probes the density of states of a material''... What does this actually mean?
  46. R

    Focal Lengths of Two Lenses of a Microscope

    A microscope is made in a tube 25.0 cm long. It magnifies 5.00 x 102 times, 50.0 times by the objective lens and 10.0 times by the eyepiece. What are the focal lengths of the two lenses?
  47. A

    Microscope with CCD camera

    Homework Statement A CCD camera with 1024x768 pixels with a pixel pitch of 6 micrometres is positioned at the primary image of a microscope with a x60 objective and a 160mm tube length. The resultant image is viewed on a video monitor with a diagonal size of 43cm and an aspect ratio of 4:3...
  48. E

    Compound Microscope Homework: Magnifying Power & Lens Separation

    Homework Statement A Homemade compound microscope has, as objective and eyepiece, thin lenses of focal lengths 1cm and 3cm, respectively. An object is situated at a distance of 1.20cm from the objective. If the virtual image produced by the eyepiece is 25cm from the eye, compute (a.) the...
  49. H

    How large is specimen under microscope?

    Hello, I thought I help my nice with her microscope. We want to know how large some plant cells are that we're looking at. Hoe do we do that? There is no scale inside the microscope so I wonder if it possible to work out how large the field of view is with a certain lense. What do we have...
  50. M

    Compound Microscope: Solving for Objective Focal Length

    A compound microscope has the objective and eyepiece mounted in a tube that is 18.0 cm long. The focal length of the eyepiece is 2.08 cm, and the near-point distance of the person using the microscope is 25.0 cm. If the person can view the image produced by the microscope with a completely...
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