Light Microscopy and Electron Microscopy

• • Light microscopes use light to view the specimen.
• Light microscopes have been used a lot to study cells, as they have allowed us to make important discoveries about the structures inside cells.
• Microscopes allow us to magnify.
• What Magnify means: the image that they produce is much bigger than the actual object.
• Disadvantages of Light microscopes: 1. Light microscopes have a limited magnification. 2. Light microscopes have a limited resolution.
• What magnification means: can not easily view structures inside, like the nucleus, because the magnification is not powerful enough.
• What resolution means: that the image is blurred, not able to see fine detail.
• Advantages of an electron microscope: 1. have a much greater magnification than light microscopes. 2. have a much greater resolution than light microscopes.
• What is the equation of calculating the magnification of a microscope?


  Here is the triangular equation to learn from.

  
• How to observe onion cells (plant cells) under a light microscope. 1. cut a very thin layer of cells from the tissue sample to be placed on the slide. 2. add a few drops of iodine to stain the onion cell, because the structures within the cell can be observed. 3. place a cover slip on top of the specimen.
• What are the different units in microscopy?


  Here is how you convert these different types of units.

  
• Electron microscopes allow smaller structures to be viewed in more detail. By this, it has improved our understanding of sub-cellular structures.
• Disadvantages of using an electron microscope. 1. It's expensive. 2. Not portable. 3. Only show black and white micrographs.
• Advantages of using a light microscope: 1. It's cheap. 2. small and easy to carry. 3. easy sample preparation.