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    The Discovery Of The Electron The electron was discovered in 1895 by J.J. Thomson in the form of cathode rays, and was the first elementary particle to be identified. The electron is the lightest known particle which possesses an electric charge. Its rest mass is Me <approximately equal> 9.1 x 10 -28 g, about 1/1836 of the mass of the proton or neutron. The charge of the electron is -e = -4.8 x 10^-10 esu <elec trostatic unit). The sign of the electron's charge is negative by convention, and that

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    The Discovery of the Electron

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    about the makeup of matter, in different ways and with different conclusions. In this instance I will be looking at the discovery of the electron, how our understanding of it has changed over the years, and measure how it has contributed to where we are today. Joseph John Thomson (J. J. Thomson, 1856 - 1940) is widely recognized as the discoverer of the electron. Thomson was a Professor of Experimental Physics at Cambridge University, and Director of its Cavendish Laboratory, from 1884 until 1919

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    Electron transfer mechanism Anaerobes have potential to reduce organic compounds to support metabolism without oxygen but exoelectrogens have tendency to transfer electrons directly to chemicals that are not intermediate electron acceptors. Anaerobes transfer electrons to soluble compounds like nitrate and sulfate which can diffuse through cell membrane to cell, but exoelectrogens like Shewanella and Geobacter species are capable to transfer electrons outside of the cell [11]. Biofilm technologies

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    Electron Microscopy Investigation The electron microscope was first made when biologists found a problem with the resolution of a light microscope. Resolution means “the ability to distinguish between two points”; the problem is that the maximum resolution of a light microscope is 200nm. So if two points are closer together than 200nm they are seen as one. One example of this problem is that under a light microscope the centrioles in an animal cell appear as one, however when viewed under

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    Electron Microscope

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    Electron Microscope The electron microscope has become one of the most widely utilized instruments for materials characterization. An electron microscope is a scientific instrument that allows us to “see” objects so small that they cannot be seen in any other way. (CITE) Electron microscopes have allowed scientists to see individual molecules and atoms for the first time. Most microscopes, including those in schools and laboratories today, are optical microscopes. They use glass lenses to enlarge

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    Electron microscope is a powerful tool that enables the study of particles in nanometer range. The invention of compound microscope in 1590 started to way to a new era of microscopy. The primitive microscope could magnify the object 20 to 30 times its original size. With more development in the field of optical microscopy by the beginning of the 20th century optical microscopes became more powerful and are capable of magnifying objects to 1000x their original size. In spite of this tremendous improvement

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    Ratio of Charge to Mass for the Electron Introduction: The object of this lab was to determine the measure of the ratio of an electron to its mass. This is done by accelerating a stream of electrons through a measured potential difference. The stream of electrons moves through a uniform magnetic field. It is perpendicular to the velocity of the electrons. The path of the electrons is circular because of this fact. The ratio of e/m can be found by the relationships between the measured accelerating

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    have three subatomic particles, protons, neutrons and electrons. The atom, the smallest unit of matter which means it’s the smallest thing that takes space and has mass is so small it would take a million of atoms to cross this dot. Knowing they’re incredibly tiny, the electrons having a single negative charge; they move around the nucleus where the protons with a single positive charge and the neutron who does not have a charge are packed. Electrons are only ones that are involved with the chemical

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    Investigation of Positively and Negatively Charged Electrons To try and find out if positively charged electrons deposit to the negatively charged electrons. This means, the electrons in the cathode attract electrons from the anode so they move towards the cathode from the anode. Prediction: I think that as the electrons move from the anode to the cathode, the mass of the anode to the cathode, the mass of the anode decreases whilst the mass of the cathode increases. I can support

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    Scanning Electron Microscope

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    instruments is the scanning electron microscope (SEM). This instrument can be used in examining physical evidence found at crime scenes. There have been a number of scientists that have developed and improved the SEM. SEM is very significant in forensics because it can narrow down size, shape, and chemical composition. The scanning electron microscope is always growing and becoming a great impact on forensic science. We will start of learning where the scanning electron microscope (SEM) began. Knoll

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    Comparing the Light and Electron Microscope In this essay I am going to be comparing the light and electron microscope, I will look at the advantages and disadvantages of each microscope and then analyse my findings to see if one is better than the other. The light, or optical microscope as it is also known was invented in the 17th century, it has been refined in many ways over the years but it is essentially still the same. The light microscope works by; light rays from a light source

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    Scanning electron microscopy (SEM) technique was employed extensively through want this study to examine and obtain images of prepared samples. The associated analytical facility of Energy dispersive X-Ray (EDX) analysis was used to identify and quantify the elemental composition of the prepare samples. These different techniques are essentially part of one instrument. The EDX facility (an X-Ray detector and associated software) is incorporated intimately as part of the SEM itself. The EDX facility

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    compound is significantly affected by the availability of electrons. The influence availability of electron density is affected by following factors: inductive effect, mesomeric effect, electromeric effect and hyperconjugation. Inductive Effect In chemical makeup and science, the 'Inductive Effect' is an experimentally observable impact of the transmitting of charge through a chain of atoms in a molecule. It can also define as the process of electron displacement along the chain of carbon atoms. It is

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    structure and composition of matter. In the early 1950s, the scanning electron microscope (SEM) was developed and it added a new element to forensic science, which was previously unattainable within the restrictions of the ordinary light microscope. All other traditional microscopes use light coming off the specimen to produce a magnified image (Saferstein, 2011). The SEM is a special microscope in the sense that it uses electrons instead of light to produce an image. This type of microscope has

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    Electron Microscopy and the Study of the Cell Electron Microscopes have revolutionised today’s understanding of the cell. In 1838 Scheleiden, a botanist theorised that the basic unit of a plant was a cell, the following year the scientist Schwann came up with a similar hypothesis this time related to animal cells, their combined ideas gave us the cell theory, the idea that all living things were made from similar building blocks, cells. It took 100 years before this idea was confirmed

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    channel protein made exactly for its size and shape. 2. These membranes are very important to the electron transport chain. This is because they house the membrane proteins that make up the electron transport chain. The two electron transport chains are similar in that they both make ATP by chemiosmosis, and they are different in the fact that they pump protons in different directions: the electron transport chain in the thylakoid layer pumps protons in the cell (from an area of low concentration

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    .. ... middle of paper ... ...In this microscope the electrons are speeded up in a vacuum until the wavelength is only one hundred thousandth that of white light. The beams of these fast moving electrons are focused on a cell sample and are absorbed or scattered by the cell’s parts to form an image on an electron sensitive photographic plate. The electron microscope can magnify objects up to 1 million times. Nevertheless, the electron microscope does suffer from a serious setback, no living specimen

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    The e/m (electron charge: mass) of electrons Aim The aim of this experiment was to study the movement and trajectory of an electron that moves perpendicular to a magnetic field and measure the charge-to-mass ratio of an electron. Abstract An electron beam was fired through a magnetic and electric field. These two fields are connected to two power supplies and these power supplies are altered. The alteration of these voltages will change the strength of the electric and magnetic fields. Varying

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    The Principles and Limitations of Transmission and Scanning Electron Microscopes Introduction Microscopy has a major role in cytology.From the very beginning researchers have tried to develop ways of looking directly at living cells.This examination has revealed much about the morphology of cells and tissues.In recent years,development in microscopes,dyes,staining and preparatory techniques have helped reveal even more about the structure and function of cells.Microscopes have a certain

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    Electron Tunneling Essay

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    Quantum Electron Tunneling Introduction Tunneling is a quantum mechanical effect. The phenomenon of tunneling cannot be explained by the classical mechanics. Classical mechanics have no counterpart to explain this. Tunneling is the major part of quantum mechanics and has a wide role in quantum. In quantum mechanics electrons have both wave like properties and particle nature. Tunneling is an effect of wave like nature. [ ( Lo, S. H., Buchanan, D. A., Taur, Y., & Wang, W. (1997). Quantum-mechanical

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