Microscopes
- Created by: Freja
- Created on: 12-04-21 11:32
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- Microscopes
- Resolution- the ability to see individual objects as separate entities
- Magnification- how many times larger the image is than the actual size of the object being viewed
- Magnification= image size /actual size
- Types of Microscope
- Light microscopes
- Magnification = x2000
- Small and inexpensive
- No vacuum required, so can see living and dead specimens
- Produces colour images
- Has a simple complex preparation, so there is usually no distortion
- Resolution = 200nm
- Laser Scanning Confocal Microscope
- The specimen is usually tagged with a fluorescent dye, and a laser is moved across the specimen
- The pinhole means that any out-of-focus light is blocked, so the microscopes produce a much clearer image than a normal light microscope
- They can be used to look at objects at different depths in thick specimens
- Has a high resolution and a high magnification
- Only light radiated from very close to the focal point is detected and the detected image is projected onto a computer
- Can produce 3D images
- Electron Microscopes
- Use beams of electrons to form an image
- Have a higher resolution than light microscopes, so they give a more detailed image
- 2 types
- Transmission Electron Microscope
- A beam of electrons is transmitted through a specimen
- Denser parts of the specimen absorb more electrons, which makes them look darker
- Has the best resolving power of 0.5nm
- Scanning Electron Microscope
- A beam of electrons is sent across the surface of a specimen and the reflected electrons are collected to produce a 3D image
- Has a resolving power of 3-10nm
- Shows the surface of the specimen
- Transmission Electron Microscope
- Magnification of up to x500000
- Due to greater magnification and resolution, electron microscopes enable you to see the ultrastructure of cells
- The beams of elctrons have a wavelength of less than 1nm
- Light microscopes
- Units of measurement
- cm to mm = x10
- mm to um = x1000
- um to nm = x1000
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