A comparison between light microscopes with electron microscopes
A comparison between light microscopes with electron microscopes The word microscope comes from the Greek words micron, meaning small, and scopos, meaning aim. To date, it is still unclear as to who actually invented the light microscope. It has often been said that Hans Janssen and his son Zacharias Janssen were the ones to have invented the light microscope in 1590, but this date is very unlikely considering Zacharias was born in 1590. It has also been said that Galileo Galilei was the inventor as he developed a light microscope with a convex and a concave lens in 1609. His microscope was celebrated in the 'Lynx Academy'. In the late 1600s, Christiaan Huygens developped a simple 2 lens ocular system which was corrected and therefore a step forward in the microscopic development. One man, however, is generally credited with bringing the microscope to the attention of biologists. Anton van Leeuwenhoek. His home made microscopes were very small simple instruments with a single very strong lens. Though awkward to use, they enabled seeing highly detailed images. Due to the limitations of light microscopes, electron microscopes were developed. In the 1930s, biologists found that light microscopes had theoretical limits, and the scientific desires to see fine details of the interior structures of organic cells were increasing. The first type of electron microscope to be
What Are the Advantages and Disadvantages of A Light And Electron Microscope?
WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF A LIGHT AND ELECTRON MICROSCOPE? The naked eyes are not powerful enough to see any type of ultra structure, such as a living or dead cell and its components. So, to further scientific stuffy the microscope invented; the light microscope. The light microscope, relatively small and light weight to the electron microscope, is the earlier discover of both types of microscopes, which I am going to discuss today. As with everything it has its advantages as well as its disadvantages. This certain microscope can magnify any sample up to 2000 times its original size. This is useful for scientists because if the species were alive you can monitor movement of the cell. The magnification allows the cell structures to be observed too. The magnification means that it gets bigger, so when you focus the knob it becomes larger. Furthermore, the light microscope produce an image which are I colour. When I stained a specimen on my slide for microscopy, I saw the colours which were very vivid. They are also easier to use. Also it is comparatively cheaper than the second microscope up for discussion- the electron microscope. As the light microscope was made very early on, as mentioned once before, it does have a lot of limitations due to that age. The only and maybe the most significant problem is its inability to show the finer details of any
An Essay about Microscopes
Microscopes The word Microscope it given to the tool used to view object that are too small to be seen with the naked eye. During the 1st century AD, glass had been invented and the Romans were looking through the glass. They experimented with different shapes of clear glass and one of their samples was thick in the middle and thin on the edges. They discovered that if you held one of these pieces of glass over an object, the object would look larger. Before microscopes as we know where invented, what was considered as a microscope was just really a Magnifying Lens, early biologist used them to study tiny insects such as Fleas, thus the viewer was called a Flea Lens. Two Dutch spectacle makers in the 1590's (Zaccharias Janssen and his father Hans) experimented with lenses and realised that if several lenses were put into a tube and the object is viewed it appears larger than viewed by any magnifying lens, this was the invention of the Compound Microscope. Anthony Leeuwenhoek of Holland who worked in a dry goods store had a great interest in lens and began making some of his own. By grinding and polishing, he was able to make small lenses with great curves. His rounder lenses produced greater magnification. Anthony Leeuwenhoek's new microscope got him interested in science and with his new improved microscope was able to see things that no man had ever seen before. He saw
Electron microscopes allow the viewer to see much smaller objects than the original light microscopes. The wavelength of electrons is thousands of times smaller than the wavelength of light
Electron Microscopy Electron microscopes allow the viewer to see much smaller objects than the original light microscopes. The wavelength of electrons is thousands of times smaller than the wavelength of light, with a ratio of around 0.01nm : 500nm, electron wavelength : light wavelength. This overcomes some of the problems faced with light microscopes, such as the depth of focus that can be obtained, the obstruction of objects and the blurred images that often occur due to the wavelengths of light. Electron microscopes can therefore show more detail then light microscopes and can be used to study much smaller objects in finer detail. As electrons cannot be seen as light can, the image is shown on a screen when the electrons are detected within the microscope. A stream of electrons is formed at a hot cathode, or 'electron gun' inside the microscope, which is then 'fired' at the object being viewed using positive electrical charges. Metal apertures and magnetic lenses are used to confine the stream into a thinner, more focused beam. The beam is then directed onto the sample by magnetic lenses. The electrons are detected by a fluorescent screen or photographic plate at the front of the microscope, causing the screen to glow and producing an image of the subject. Due to the finite energy of the electrons, care must be taken in the preparation of the specimen for viewing, and
How to use a Light Microscope
How to use a Light Microscope Introduction: In this coursework I will be using a simple light microscope to look at the letter 'e' which will be cut out from a past newspaper. I will be trying to find out how a microscope works, and what I see through the eyepiece when looking at the letter 'e' and what changes occur when changing the focus and slide. Before I begin the experiment I will be introducing exactly what a microscope is and how it is used. Microscopes are instruments that magnify tiny objects or reveal fine details on larger objects, they reveal to us things that are invisible to our eyes such as cells. The two commonly know microscopes are 'Electron Microscopes' and 'Optical Microscopes', electron microscopes use a beam of electrons controlled by magnetic fields instead of light and electron microscopes are very powerful and can show details 1000 times larger than optical microscopes but the specimen must be dried out and sliced very thinly. In an optical microscope, light shining through an object is bent as it passes through a lens and this will make the object appear bigger than it is and by adding a second lens the magnification will then increase. Optical microscopes with several lenses are called compound microscopes and this is what I will be using in the experiment. Equipment/Apparatus: * Cover Slip * Slide * Small Strip of Newspaper with the
The history, development and use of the light and electron microscope
The history, development and use of the light and electron microscope History of light microscope Observing objects in detail greater than the naked eye was very interesting to people at early stage. This led to the construction, in the 16th century, of a magnifier composed of a single convex lens, and this, in turn, led to the eventual development of the microscope. The most famous early pioneers in the history of the microscope are Digges of England and Hans and Zcharias Janssen of Holland. But it was Antony van Leeuwenhoek who became the first man to make and use a real microscope. Leeuwenhoek ground and polished a small glass ball into a lens with a magnification of 270X, and used this lens to make the world's first optical microscope. Because it had only one lens, Leeuwenhoek's microscope is now referred to as a single-lens microscope. Its convex glass lens was attached to a metal holder and was focused using screws. The light microscope system was invented in the seventeenth century. This type of microscope incorporates more than one lens so that the image magnified by one lens can be further magnified by another. Today, the term "microscope" is generally used to refer to this type of compound microscope. Since its invention, the light microscope has made tremendous progress and help figure out many biological molecules. Using a light microscope that he had
The purpose of this laboratory investigation is to verify the validity of the Lens Equation which states that 1/di + 1/do = 1/f.
Lab: Applying the Lens Equation Daniela Perdomo Lab Partner: Stephanie Landers Date: 21 November 2002 Place: Graded School - São Paulo, Brazil Time: 8:10 h - 9:35 h Purpose/Introduction: The purpose of this laboratory investigation is to verify the validity of the Lens Equation which states that 1/di + 1/do = 1/f, where di is the distance from the image to the lens, do is the distance from the object to the lens, and f is the focal length. Hypothesis: The laboratory investigators hypothesized that the data obtained in the procedure of this experiment would be consistent with the Lens Equation. Though different methods of obtaining focal lengths (f) will be used throughout the lab, the obtained f's should still be equal. Materials: * 2 double convex lenses * 1 candle * 1 box of matches * 1 meter stick * 1 lens holder * 1 cardholder * 1 candleholder * 1 blank card Diagram: Procedure: The first lens used in this investigation was a double convex lens, which indicates that light should converge when shone through it. The first way used to discover its focal length was by using sunlight. A cardholder, with a card in it, was placed on the meter stick and the lens holder, with the convex lens in it, placed in front of it (i.e. closer to where the sunlight was coming from). The lab investigators then moved the lens until the image on the card was focused enough
How has the Invention of Contact Lenses affected people's Sight?
Manon Mollard MP5a 14.12.04 Biology: The Impact of Man's Inventiveness on the Human Body. How has the Invention of Contact Lenses affected people's Sight? Introduction People with sight troubles have had the possibility of wearing glasses for a really long time, but the new technology made available contact lenses. In this essay, I am going to look at the different contact lenses types that exist, at who invented them and when, for which vision problems they are solution, at how to take care of them, at how common they are in our society and finally, I will write about my own opinion. What contact lenses are According to the Macmillan Dictionary (2002), contact lens may be defined as "a plastic lens that you wear in your eye to help you see more clearly". A very wide variety of contact lenses are available in today's society, including hard and soft (even if soft is by far more common now), disposable and extended wear; this makes it easy for each person to chose the appropriate type of contact lens for her. The main types of contact lenses are listed below: * Soft lenses: As these lenses are soft, they are made of a large percentage of water, and this allows oxygen to pass through the lens and reach the cornea. They are also more comfortable and easier to adapt to. * Rigid-gas
To Determine the Focal Length of a Convex Lens.
To Determine the Focal Length of a Convex Lens. Aim: To determine the relationship between the power of the vocal lens, object and the image distance from the lens. Apparatus: Bulb Projector Convex lens Lens holder Screen Optical Bench 12V power supply Diagram: Method: * Set up the apparatus as shown in diagram. * Put the focal lens at the first distance shown on the results. Also put the object at the 0 point of the optical bench. * Switch the 12V bulb and move the projector until a clear picture of the object is visible. * Record the results on the results table of the distance from the lens to the projector * Keep on moving the object to the 6 points shown on the results table and record the distances when object is visible for each measurement * I will do the experiment twice for each measurement to ensure that the results are accurate Safety: Making sure that all bags are put under tables will make this experiment safe. Also the work surface will be cleared of all books and other mess, which will mean that the table will be empty and easier to work on. The bulb will be hot so I will make sure that no one touches it or looks directly at it because it will also be very bright. Theory: The distances from the lens to the screen (U) as well as measuring the distance from the lens to the projector (V) will make me think of a formula. I have obtained a
Setting up a Light Microscope.
Setting up a Light Microscope Aim: To set up a Light Microscope Microscopes came into existence in 1670. It was a man called Antoni Van Leeuwenhoek who came up with this innovative idea of inventing a Microscope. Soon his invention was very popular. Scientists everywhere started to utilize similar microscopes. Microscopes have been an asset to the scientific industry. We nowadays use microscopes to things in a greater detailed picture. The naked eye cannot see an onion cell, to observe the onion cell we need to use a Light Microscope. When using a Light Microscope we can adjust the magnification to what we desire. A light microscope is an excellent piece of equipment to use when distinguishing between an animal and plant cell. There are many types of microscopes. Two common microscopes are the Light Microscope and the Electron Microscope. Electron Microscopes are those that are used in big science laboratories. They can magnify up to a huge 500,000x. Whereas, a standard light microscope can only magnify upto 1000x. There is also a massive price difference between the two microscopes. An Electron Microscope can cost up £2.5 Million and a good light microscope will only cost about £50. Method You have to be very careful when using a light microscope. Follow these i9nstructions to setup and use the microscope properly. * First of all place the microscope in the