A microscope is an optical instrument that magnifies objects that are too small to be seen by the naked eye. Microscopes are used by a variety of science related fields such as engineering. For example a biologist and botanist use microscopes to look at cells. Engineers use microscopes to examine fracture patterns in metals. Basically anyone can use a microscope to examine small objects but scientists and researchers use microscopes on a daily basis. There are a variety of microscopes available such as, light microscopes (commonly referred to as optic microscopes), electron microscopes, scanning electron microscopes, and comparison microscopes. Microscopes differ in terms of illumination sources, magnification ranges, and their everyday uses. First of all illumination sources differ amongst microscopes. An illumination source is the radiation or the light that supplies and brightens an object. The illumination source for light microscopes is visible light. The illumination source is used as daylight and is directed to the object using a mirror. The illumination source for electron microscopes uses a high voltage electron beam that carries the image of the specimen. The illumination source, the electron beam, is produced by an electron gun and it is accelerated by an anode. A light microscope uses visible light as their light source whereas an electron microscope has beams of electrons focused by magnetic lenses. Last but not least the scanning electron microscope (SEM) uses a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens. This microscope differs from the light microscope in that it examines the surface of objects using an electron beam. Both transmission and scanning electron microscopes use a high-voltage power source to drive an electron gun but the scanning electron microscope is based on scattered electrons while the electron microscope is based on transmitted electrons. In addition to illumination sources, the magnification ranges differ amongst microscopes. In dealing with microscopes the magnification range means how large an object can appear. The magnification range for the light microscope is up to 1500 times. The actual power or magnification of an optical microscope is the product of the powers of the ocular (eyepiece) and the objective lens. The magnification range for the electron microscope is up to 10,000,000 times whereas light microscopes are limited by diffraction and their magnifications are below 2000 times. An electron microscope has greater resolving power which means that it can reveal the structure of smaller objects because electrons have shorter wavelengths than visible light. The magnification range for scanning electron microscopes is 15 times to 200,000 times. This means the scanning electron microscope is a powerful and flexible tool for solving a wide range of product and processing problems for a diverse range of metals and materials. The SEM is similar to the electron microscope in that its magnification range is larger than the light microscope. Finally, because of their illumination sources and magnification ranges, microscopes are used for different purposes. Some possible uses for a light microscope are viewing dead
suspects clothing would be compared with glass from the broken window at the crime scene, referred to as the control sample.
The glass can be collected and examined in the following ways:
Scanning Electron Microscope (SEM)
Physical matching remains the most definitive means of establishing a common origin between any samples. If the forensic scientist can fit the two samples of glass together to form one item, then they can determine that the samples have…
Responsible Business Report 14/01/2015
By Kyle O’Shea.
Student number: 13144426
Course: Responsible business, Year 2.
Intended audience: Liz Walley.
Topics discussed: Drivers of responsible businesses (Role of government and Competitive advantage.)
Word Count: 2181
Table of Contents
1.0 Introduction………………………………………………………….pg 5
2.0 Responsible Business…………………………………............pg5
2.2Sustainable Development /Corporate Citizenship………..pg6…