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SAgE

An Introduction to Electron Microscopy and its Applications

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Description: 

We welcome visits from key stage 5 pupils and their teachers to the electron microscopy laboratory at Newcastle University's Medical School. During their 1.5-2 hour visit they will learn how specimens are prepared for both scanning and transmission EM and see the electron microscopes in action. Visits are suitable for both year 12 and year 13, though numbers are restricted (min 7, max 14).

Cost:

£10 per pupil.

Request a Visit:

Please contact us to request a visit. Please indicate approximate number of students and two or three suitable dates. We will be in touch.

Further information about EM Research Services.

 

Further Information on Electron Microscopy:

The naked eye can only distinguish between two points 0.2mm apart or more. This distance is called the resolving power of the eye.

A light microscope can resolve two points 0.0002mm apart, which allows magnification up to 1000x.

This resolution cannot be improved upon as the limiting factor is the wavelength of light. To increase the resolving power, therefore increasing useful magnification, something with a shorter wavelength than light is required.

Electrons have a wavelength 100,000 times shorter than light but the environment in which they are used needs to be carefully controlled.

As electrons are easily stopped or deflected by matter, the column of the microscope must be under vacuum to remove air molecules that would interfere with the beam. Magnetic fields have the same effect on electrons as glass lenses have on visible light therefore electro-magnetic lenses are used to focus the electron beam.

Electron Microscopy Research Services at Newcastle University houses two types of electron microscope, Transmission EM (TEM) and Scanning EM (SEM).

The TEM is used to look at the internal structure of the specimen by passing an electron beam through a section of the specimen. Samples must be very thin, about 70nm, to allow the electrons to be transmitted through the specimen. TEM magnification from x100 to x1000000

Typical Applications for TEM:

  • Plant and animal tissue and cell culture
  • Isolated proteins
  • Bacteria and viruses
  • Detergent extracted cytoskeleton and organelles
  • Particulate size and distribution in non-biological samples

 

The SEM scans across the surface of the specimen providing an image of the surface detail.  SEM magnification from x20 to x250000.

Typical applications for SEM:

  • Plant and animal tissue
  • Biofilms
  • Dental research
  • Bacteria

Samples for both TEM and SEM need to be preserved and prepared in a specialised way before viewing.

You can find out more about the Electron Microscopy facility at Newcastle University via our EMRS website.

Downloads: 

Scanning electron microscopy image of Anenome pollen
 
False coloured SEM image of hairs on Taratula foot
 
SEM image of the tip of a dragonfly's wing
 
SEM images of Streptococcus bacteria and macrophage
 
 Low magnification SEM image of anenome pollen
Relevant subjects Type of activity Suitable audiences
  • Medicine and Dentistry
  • Biology
  • Events on Campus
  • Resources
  • Y 12
  • Y 13
  • KS 5