B1.1- The world of the microscope
- Created by: H_Coveney
- Created on: 09-12-17 15:19
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- B1.1- The world of the microscope
- Light microscopes
- Was first developed in the mid-17th century and are still used today.
- They use a beam of light and lenses to form an image.
- They can magnify up to x2000 but most only magnify several hundred times.
- They are relatively cheap.
- They can be used to magnify live specimens, cells and large subcellular structures e.g. nuclei.
- They can be used almost anywhere.
- Electron microscopes
- Was first developed in the 1930s.
- They use a beam of electrons to form an image.
- They can magnify x2,000,000
- They are very expensive.
- They are large and have to be kept in special temperature, pressure and humidity controlled rooms.
- They allow us to see smaller things in more detail e.g. internal structures of mitochondria and chloroplasts and evne smaller things like ribosomes and plasmids.
- They have a higher resolution.
- Transmision Electron Microscopes (TEM)
- Give 2D images with very high magnification and resolution.
- Scanning Electron Miscroscopes (SEM)
- Give dramatic 3D images but with lower magnification.
- Magnification and resolving power.
- magnification = size of image / size of real object
- resolution- the ability to distinguish between two separate points, not appearing as one object (sharper image)
- resolving power of a microscope- is how much detail it can show.
- Light microscopes
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