• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Microscopes are used to show the internal structure of materials. They also give biologists/ physicist the power to magnify and distinguish objects that are not visible by the human eye.

Extracts from this document...

Introduction

Microscopes How can we find out the structure of several materials? For instance wood, the grains of wood reveal its structure. But there are certain materials where the structure cannot be seen by the human eye or felt. For example a coin or a piece of rubber will appear "smooth" to the naked eye. Microscopes are used to show the internal structure of materials. They also give biologists/ physicist the power to magnify and distinguish objects that are not visible by the human eye. Light microscopes have improved the knowledge in biology, biomedical research and materials science. Light microscopes can magnify objects up to 1,000 times, revealing microscopic details. The light microscope, so called because it allows visible light to detect small objects, is probably the most well known and well-used research tool in biology. ...read more.

Middle

Electron microscopes are scientific instruments that use a beam of highly energetic electrons to observe objects on a very fine scale. Electron microscopes have a focused beam of electrons instead of light to have a "image" of the object, and gain information of its structure and composition. How they work: 1. A stream of electrons is formed and accelerated towards the object using a positive electrical potential. 2. This stream is a thin focused monochromatic beam. 3. This beam is focused onto the sample using a magnetic lens. 4. The electron beam interacts with the sample, affecting its focus. Grass Hopper, viewed using an electron microscope It's not possible to see an electron beam, so the electron beam is projected on to a fluorescent screen so that the image can be viewed. ...read more.

Conclusion

A great depth of information is achieved, even using the same magnification and resolution as the light microscope such detail cannot be achieved because you would constantly have to keep on focusing up and down. The disadvantage of this is that it cannot have the same resolution as the TEM. The transmission electron microscope (TEM) works by passing a beam of electrons through the specimen before it was viewed. Electrons that passed through the specimen are seen. This means that thin sections of the specimen are seen, such as the insides if cells. The advantage light microscope over electron microscopes is its ability to observe living organisms and tissues. Various types of electron microscopes require the specimen to be coated with gold and placed in a vacuum chamber. What ever form of life is present will not survive under these conditions. Where as a light microscope allows once to observe living organisms. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Microscopes & Lenses section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Microscopes & Lenses essays

  1. Optical and Electron Microscopy

    The final image will show different tones of black and white depending on the densities of the various parts of the specimen. In those areas of the specimen that are dense, more electrons are absorbed resulting in a darker tone on the image, and those areas which are less dense

  2. Find the separation between two cones of the same type on the fovea of ...

    * The perpendicular distance that the viewer of the light sources can be from them and still completely resolve them. This will vary as a direct result of changes to the separation of the light sources. * The size and shape of the light sources.

  1. History of the Microscope

    the objective lens, or the lens closest to the object. Before purchasing or using a microscope, it is important to know the functions of each part. This information is presented below. Links will take you to additional information and images.

  2. My experiments focus is to obtain an accurate measurement for a specific lenss power.

    These components were placed on one end of the desk with the middle of the filament lamp aligned with "0" millimetres on the ruler. 3. Then I put the lens in the holder and placed it on top of a wooden block.

  1. Use of the material Zerodur in the KECK observatory telescope. The very low CTE ...

    Stainless steel - 17.3.5 Clearly then, with varying conditions within the building in which the telescope is housed; using other materials such as stainless steel would have caused major problems for the mirror. For example, using stainless steel; CTE: 17.3 �m m-1 K-1 Expansion for a temperature change of 5

  2. The eye.

    Nearby objects can be seen more easily. Eyeglasses with concave lenses correct this problem by diverging the light rays before they enter the eye. 2) Hypermetropia (long sight) Farsightedness. If the eyeball is too short or the lens too flat or inflexible, the light rays entering the eye - particularly

  1. When two objects are placed close enough to each other or are a great ...

    The resolving power of the unaided eye does differ from one person to another due to the fact that not all individuals have the same vision or strength of eyes. Therefore, not all individuals have the same resolving power.

  2. Electron Microscopes

    The third lens, the projector allows further magnification, and the selection of the area of the image to be viewed. As the path of the electron beam could be impeded by collisions between the electrons and air particles, the electron beam passes through a vacuum.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work