Microscopy
Microscopes are tools which allow us to see objects which we cannot see with the naked eye. There are two main types of microscopes used nowadays. These are light microscopes and electron microscopes.
During the 16th century the microscope was invented, which was of great assistance to works in medicine and biology. At first, the microscope was basically used recreationally, and was found in the homes of wealthy people. However, not long afterwards, proper uses for the microscope were discovered, and so study of bacteria and diseases began.
History of the microscope:-
- Circa 1000AD – First vision aid was invented called a reading stone. It was a glass sphere that magnified when laid on top of reading materials.
- Circa 1284 - Italian, Salvino D'Armate invented the first wearable eye glasses.
- 1590 – Zaccharias Janssen and his son Hans Janssen experimented with multiple lenses in a tube and observed that objects appeared greatly enlarged
- 1665 – Robert Hooke noticed some "pores" or "cells" in a sliver of cork looking through a microscope.
- 1674 – Anton van Leeuwenhoek built a simple microscope with only one lens to examine blood, yeast, insects and other tiny objects. He invented new methods for grinding and polishing microscope lenses that allowed for curvatures providing magnifications of up to 270 diameters, the best available lenses at that time.
Leeuwenhoek’s microscope
- 1872 – Ernst Abbe wrote a mathematical formula - "Abbe Sine Condition". His formula provided calculations that allowed for the maximum resolution in microscopes possible.
- 1903 – Richard Zsigmondy developed the ultra microscope that could study objects below the wavelength of light.
- 1932 – Frits Zernike invented the phase-contrast microscope that allowed for the study of colourless and transparent biological materials
- 1931 – Ernst Ruska co-invented the electron microscope.
- 1981 – Gerd Binnig and Heinrich Rohrer invented the scanning tunnelling microscope that gives three-dimensional images of objects down to the atomic level. Binnig and Rohrer won the Nobel Prize in Physics in 1986. The powerful scanning tunnelling microscope is the strongest microscope to date.
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Peer Reviews
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Quality of writing
The candidate has accurately used scientific terms, with the exception of the term light microscope which is more accurately described as an optical microscope and this is term I would expect and A-level candidate to use. However the essay is coherent and it is clear that the candidate understands the topics they are discussing. Though there a few spelling errors, which possibly could have been avoided if the candidate had thoroughly proof read their work.
Level of analysis
The candidate uses bullet points to state the relevant facts relating to the development of microscopes, and they have put together a table to show the comparison of different types of microscopes, while is fine for your notes for even an essay plan, it is not something that I would encourage you to include in an essay. It is more appropriate to write this type information in a paragraph so that you can provide further detail. At this level of qualification you should be able to write scientific information in prose. That said the candidate does provide a great deal of information and has possibly undergone independent research, which shows interest and dedication in your subject and can make your essay more enjoyable to read. Unfortunately though, there is no conclusion to this essay, this is a mistake, without a clear conclusion, your essay ends abruptly, whereas if you take the time to summarise your key points and include a personal response you can leave the reader with a good impression of your work.
Response to question
The candidates introduction starts off well, they introduce the term light microscope, they explain what a microscope is and what it is used for. This is very good, however an introduction should also clearly state exactly what you plan to discuss so that the purpose of your essay is clear. That said the candidate gives a very detailed account of the different types of microscopes and has used appropriate technical terms throughout.
