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Essay on microscope history
Essay on microscope history
Essay on microscope history
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MICROSCOPY
Microscopy is the technique to examine minute objects through microscope which can not be seen by naked eye. (1)
HISTORY OF MICROSCOPY
SCIENTIST YEAR CONTRIBUTION
Hans and Zacharias Janssen 1590 Created first microscope
Robert Hooke 1667 Published micrographia
Anton van leeuwenhoek 1675 Used microscope with one lens. He was first to observe bacteria.
Joseph Jackson lister 1830 Discovered that weak lenses in combination provide clear magnification
Richard zsigmondy 1903 Invented ultra microscope
Frits xernike 1932 Invented phase contrast microscope
Ernst ruska 1938 Invented electron microscope
Gerd binning and Heinrich rohrer 1981 Invented scanning tunneling microscope (2)
MICROSCOPIC TECHNIQUES
There are many microscopic
…show more content…
This technique has a very little contrast which is mostly provided by staining specimens.
• LIGHT MICROSCOPY
It is the technique that uses visible light as a source of illumination to view small objects which are in finer detail than the ability of naked eye.
HISTORY
Antony van leewenhoek invented simple microscope in 1670 which was able to magnify upto 200x so he was the first person to see individual cells.
Another scientist Robert Hooke further advanced the compound microscope by adding some additional instrumentation such as stage, an illuminator and coarse and fine adjustment knobs.
WORKING PRINCIPLE
Compound microscope contain two lenses in series
• The objective lens
• Eye piece lens
The objective produces magnified real image of the object which is further magnified by the ocular lens to obtain final virtual image of the specimen. (3) (10)
NUMERICAL APERTURE
Numerical aperture is defined as the diameter of the objective lens in relation with focal length
n.a = n sin 0
TOTAL MAGNIFICATION
The total magnification is the product of ocular magnification and objective magnification
Mt= MOB X MOC
USES
• Easy to use
• reasonably priced
• live samples can be
One can almost feel the searing penetration of Lewis Thomas’ analytical eye as it descends the narrow barrel of the microscope and explodes onto a scene of vigorous, animated, interactive little cells—cells inescapably engrossed in relaying messages to one another with every bump and bounce; with every brush of the elbow, lick of the stamp, and click of the mouse…
Prior to the invention of the daguerreotype, the Camera Obscura was the main optical instrument that was used to project images onto paper. The Camera Obscura was a device in the shape of a box that allowed light, which was being reflected from the images that the user was intending to capture, to enter through an opening at one end of the box to form an image on a surface and an artist would then trace the image to form the most accurate impression of an image at that peri...
“The camera may be thought of as a comparable to the eye. The difference is
by the internal computers of the instrument, to create an image of internal body tissues. These images were then displayed on the screen for the user,
To see a chemical at a microscopic level you would need to use a microscope versus the
.... 'It is a moment when the visible escapes from the timeless incorporeal order of the camera obscura and becomes lodged in another apparatus, within the unstable physiology and temporality of the human body'. Crary further demonstrates the shift in vision's location from camera to body by examining the way in which it was reproduced in various optical devices invented during this same period, specifically the stereoscope, the kaleidoscope, the phenakistiscope, and the diorama. His examination is based on a provocative premise: 'There is a tendency to conflate all optical devices in the nineteenth century as equally implicated in a vague collective drive to higher and higher standards of verisimilitude' (110). According to Crary, such an approach tends to neglect entirely how some of these devices were expressions of what he calls 'nonveridical' models of perception.
Now for our eyes we use them for vision, their like our own personal camera’s,
Light rays gather through the opening of the telescope called the aperture and pass through the objective lens and refract onto a single point called the focal point. From there, the light rays continue in the same direction until it hits the eyepiece lens, which also refracts the light back into parallel rays. During the process, the image that enters our eyes is actually reverse of the original image and magnified because of the size in which we perceive the image.
In the late 1660’s a scientist, Edme Mariotte, discovered the “blind spot’ in the eye. Edme noticed a hole in the eye , the optic disc, with a nerve going through it and found that it was the blind spot. Edme is the first remembers scientist to discover the blind spot. He is often remembered for his study of optics and color perception. Edme made many more discoveries in the science fields. Although Edme did not believe the blind spot was in the retina, he was the first scientist to recognize there was something weird in the eye, at which at some point you could not see an entire image, also known as the blind spot. In the vision field the blind spot is call “Mariotte’s Spot” (Edme Meriotte (1620-1684): Pioneer of Neurophysiology, n.d.).
Antonie van Leeuwenhoek was a scientist and was best known for his contributions to microbiology; he received the title of "the Father of Microbiology” and dedicated many years of his life to improve the microscope in order to attain incredible heights of precision of the microscopic lenses. He produced magnifications from up to 275X, with a resolving power of up to 1.4 µm. Moreover, he presented his findings from the material of animals and vegetables in extraordinary detail as well as being the first to observe a glimpse of bacteria that he found in water; the first illustration of the bacteria is demonstrated in a representation by Leeuwenhoek in the 1683 “Philosophical Transactions” publication. In this publication, Leeuwenhoek wrote to the Royal Society about his observations of the inside of an old man’s mouth. He found "an unbelievably great company of living animalcules [Latin for ‘little animals’], a-swimming more nimbly than any I had ever seen up to this time. The biggest sort... bent their body into curves in going forwards. . . Moreover, the other animalcules were in such enormous numbers, that all the water... seemed to be alive." These were among the first observations on living bacteria ever recorded.
Image intensification is the process of converting x-ray into visible light. “Early fluoroscopic procedures produced visual images of low intensity, which required the radiologist's eyes to be dark adapted and restricted image recording. In the late 1940s, with the rapid developments in electronics and borrowing the ideas from vacuum tube technology, scientists invented the x-ray image intensifier, which considerably brightened fluoroscopic images” (Wang & Blackburn, 2000, np). We will explore the image-intensification tube, the various gain parameters associated with the tube, and the magnification mode of the image intensifier.
Before the discovery of X-rays in 1895, it was impossible to look inside human body, without causing harmful side effects. The famous quote of Anna Bertha Ludwig - “I have seen my death” is a testimony to this. In ancient times, the only way to study internal human organs was the dissection of dead bodies. Additionally, this was also subject to availability or religious beliefs. Leonardo da Vinci made 240 detailed sketches between 1510 and 1511, which were way ahead of their time. Unfortunately, it could not be published, except for a small amount in 1632. Images aide in visualization of illnesses (e.g. a malignant tumor), which are impossible to observe from outside of the body. A surgeon must know the various attributes of the tumor like location and size, before she can operate on it. Similarly an oncologist needs this information to decide the course of treatment e.g. tumor size and metabolic activity may be needed to determine the number of chemotherapy sessions. With images, all this information can be obtained without cutting open the patient. And what’s remarkable is that u...
The origin of the biological term cell came from Robert Hooke in 1662. He observed tiny compartments in the cork of a mature tree and gave them the Latin name “cellulae”, which translates into “small rooms”. In the late 1680s, Anton Van Leeuwenhoek was the first scientist to actually lay eyes on a cell. Before, there had been theories of “cells” but no one had the technology to see something so microscopic yet. Van Leeuwenhoek ran a draper 's shop and wanted to see the quality of the thread, better than the magnifying lenses available at that time. Therefore, he began to develop an interest in lens-making, with an interest already in microscopes and a familiarity with glass
Science and Technology has been around from the beginning of time. It evolved from the everyday efforts of people trying to improve their way of life. Throughout history, humankind has developed and utilized tools, machines, and techniques without understanding how or why they worked or comprehending their physical or chemical composition. Before we go any further a definition has to be given for both Science and Technology because they are both different in their own right even though the two are almost indistinguishable. According to the Oxford Dictionary Technology can be defined as the knowledge or use of the mechanical arts and applied sciences, while Science can be defined as the branch of knowledge involving systematized observation and experiment. Science can be further divided into three separate categories; Pure, Applied and Natural Sciences. In addition technology is often defined as applied science, it is simply the application of scientific knowledge to achieve a specific human purpose, however, historical evidence suggests technology is a product of science.
Science and technology in the middle ages flourished because of the need of inventions to make life easier. In Europe, from the 5th century to the 16th century there was a radical change in the inventions made. It was between the fall of the Western Roman empire and the early modern era. This was a time for exploration in new ideas and ways of doing things. Europe invented many things for wars, time-keeping, and for everyday use. These inventions may be still used today. They range from huge mortar to a small set of eyeglasses. Europeans found that life was easier with new better inventions to help them in everything. There are a series of inventions about war because of nearby wars with neighboring civilizations or even within Europe.