This website uses cookies to ensure you have the best experience. Learn more

Light Microscope And Electron Microscopes Essay

1192 words - 5 pages

Magnification and ResolutionMagnification is how much bigger a sample appears to be under the microscope than it is in real life.Overall magnification = Objective lens x Eyepiece lensResolution is the ability to distinguish between two points on an image.· The resolution of an image is limited by the wavelength of radiation used to view the sample.· This is because when objects in the specimen are much smaller than the wavelength of the radiation being used, they do not interrupt the waves, and so are not detected.· The wavelength of light (min. - violet is 400nm) is much larger than the wavelength of electrons, so the resolution of the light microscope is a lot lower.· The actual resolution is often half the size of the wavelength of radiation used. Thus, for the light microscope the maximum resolution is about 200nm.· In other words, if two objects in the specimen are closer than 200nm in real life, then they will only show up as one object on the image.· Using a microscope with a more powerful magnification will not increase this resolution any further. It will increase the size of the image, but objects closer than 200nm will still only be seen as one point.Light MicroscopyThe light microscope is the main tool which has been used to look at biological specimens for many years and is still very much in use today. Very small subjects, such as bacteria, can be looked at whole under a microscope, but larger tissues must first be chemically preserved, embedded in wax, sliced very thinly, mounted on glass slides and stained before viewing. Some semi-translucent specimens, such as the chick and zebrafish embryos, can be looked at whole under microscopes specially designed for this purpose. In all cases, the microscope works by light being focused by a concave mirror and/or a condenser before it passes through the specimen and into an 'objective', which magnifies the subject before it is viewed through the eyepiece. Certain components of the tissue, such as nerves or a protein, can be seen by staining them with specific dyes. Some of these are fluorescent and only show up when filters are used to block out all light except that of the same wavelength as the dye.There are other variations of light microscopy, some of which are seen in this display. In Dark Field Illumination, an opaque disc is placed above the condenser of the microscope so that light around the edge of the disc is reflected by the specimen, which appears to be on a dark background. The tissues may be further emphasised by staining, as has been done in the case of the Aspergillus fungus. Differential Interference Contrast optics is another variation which relies on polarised light being slightly bent as it passes through tissues. The differences in composition of different cells causes slight changes in the bending of the light. After the light has passed through the tissue it passes through...

Find Another Essay On Light Microscope and Electron Microscopes

Structure of the cell and bio molecules

751 words - 4 pages differences of light and electron microscopes : Both light and electron microscopes use light or electron beams to form larger and more detailed images of things than the human eye can observe. The electron microscope uses electron beams instead of using rays of visible light to make the image of tiny areas of biological specimens highly magnified compared to the light microscope, as there’s two different types of electron microscope

Exploration of Light Microscopes Essay

1129 words - 5 pages Exploration of Light Microscopes What does the word microscope mean: The first part of the word "Micro" means tiny. The "scope" part means to look at or view. Microscopes are tools that are used too enlarge images of small objects so that they can be studied. A light microscope is an instrument made up of two lens they are eyepiece lens and the object lens combined they produce a much greater magnification

History of Chemistry

974 words - 4 pages use to move the microscope and there is the base where which holds up the actually microscope. There is also a stage where you put your sample you want to examine on. Overall the microscope is mainly made out of plastic and glass. The main natural resource used to make the plastic of the microscope is petroleum. Most modern day microscopes used in labs outside of the school uses electricity and use light to help function the microscope. A

Cells & Organelles Through the Electron Microscope

519 words - 2 pages observations of cells were made in 1665 by English scientist Robert Hooke, who used a crude microscope of his own invention to examine a variety of objects, including a thin piece of cork. There are two basic types of microscopes: light microscopes and electron microscopes. Light microscopes can magnify an object up to 1,000 times . Good light microscopes are powerful enough to view most algae, fungi, and protozoa . High-quality light microscopes

Microscope Lab Report

510 words - 2 pages & unbelievable resolution. During the late 1700’s, the microscope was reinvented with 1500x magnification. The most recent advancement in microscopes is the electron microscope, which was invented in 1930. This particular model uses an electron beam, instead of light & 4,000,000x magnifications with incredible resolution. There are many different parts of a microscope and each one has its own unique purpose. The compound microscope has 13 main

"Electron Microscopes" - Electron Microscopes (EMs) are scientific instruments that use a ray of electrons to examine small matter on a very fine scale

688 words - 3 pages of.*Crystallographic Information; this is how the atoms are arranged in the matter.Where did Electron Microscopes Originate from?Electron Microscopes were invented because of the limitations of Light Microscopes, which had a smaller magnification level. Two scientists named Max Knoll and Ernst Ruska from Germany in 1930, decided to develop The Transmission Electron Microscope (TEM) as there was a greater desire to see finer details of interior

Microscopes by Isobel Woosnam

742 words - 3 pages to pass through. The light passes into a strong, powerful lens called the objective lens. This is the first time the object is magnified. There is also an eye piece lens which you look through, this gives the second magnification. This lens is a bit like a small magnifying glass. (Image from http://www.microscope-microscope.org/basic/microscope-parts.htm) There are also modern microscopes called electron microscopes that can magnify upto 300,000

The Microscope

957 words - 4 pages electron beams, objects can be viewed differently and at different magnifications. Microscopes have also helped scientists learn about inherited diseases found in our DNA, by their use in the field of cytogenetics, using fluorescent microscopy. Scientists attach fluorescent tags to markers for specific genes in cells. By shining fluorescent light through these cells under the microscope, the fluorescent tags glow brightly and show the physician if the

"The Living Cell"

608 words - 2 pages with these light microscopes. Phase-contrast instruments use special equipment to reveal the refraction, or bending, of light passing through objects, enabling the viewer to see cell details not visible with other microscopes. The electron microscope uses waves of electrons, rather than light, and magnetic fields, rather than lenses, to get an image. With the aid of electron microscopes 200 times more powerful than the best light instruments, molecular biologists have learned a great deal more about the tiny structures within cells.

History of Modern Science and Technology

2508 words - 10 pages the military, to agriculture, and to even a high school laboratory. New developments are continuing to be made today on different types of microscopes especially on the electron microscope. DNA sequencing is a method that allows us to map out the entire nucleotide sequence of an individual. It benefits us because it can allow for better medical care, showing what genes you might code for so that preventative measures can be taken if a gene is

More Bio notes from next lesson on Cells and Microscopes

720 words - 3 pages show details clearly. If it weren't for the resolution of a microscope, to the viewer, everything would be a blur, and not at all useful.Light microscopes use a beam of light passing through one or more lenses to produce an enlarged image of the object or specimen being viewed. Microscopes that use sets of lenses are called compound microscopes. The ocular lens is placed near to the viewer's eye. The objective lens is positioned near the specimen

Similar Essays

Comparing The Light And Electron Microscope

1255 words - 5 pages magnify up to 500,000 times compared to the best light microscopes which magnify only around 2000 times. Whereas the light microscope uses glass lenses to focus the light rays, the electron beam of the electron microscope is focused by powerful electromagnets. The image produced by the electron microscope cannot be detected directly by the naked eye. The beam of electrons is directed on to a screen from which black and

The Principles And Limitations Of Transmission And Scanning Electron Microscopes

1149 words - 5 pages by a heated filament ,focussed on the specimen by the condenser lens and the image then magnified by the objective and projector lenses.The beam can be bent and focussed by electromagnetic lenses,in the same way the glass lenses are used in a light microscope.Unlike light microscopes ,the electron microscopes,have a high resolution(0.1 nm) and high magnification(1000000X) .The image formed by the electron microscope is

Medical Imaging The Physics Of Light Microscopes And Magnetic Resonance (Mri) Units

619 words - 2 pages below left)These hydrogen atoms, with one proton and one electron, act like 'bar magnets' with a north and a south pole. When a magnetic field passes through them, they align themselves with the field. However, this means that they can align facing in one of two possible ways: parallel or antiparallel to the field. (See right).When the hydrogen atoms align like this, the atoms that face opposite directions 'cancel' each other out. It is the

Electron Microscope Essay

856 words - 3 pages a non-zero rest mass. Electrons also have a wavelike property, which made them prime candidates for microscopes and other devices. Ernst Ruska (1906-1988), a German physicist, used De Broglie’s discovery to design a microscope that used an electron beam instead of light to produce an image. (CITE) By 1931, with the help of partner Dr. Max Knoll Ruska had produced a working model of the first electron microscope. Several types of electron