1.3: microscopes

What are light microscopes?

Simple, least expensive and most widely used microscope, which uses light and lenses to zoom

What are electron microscopes?

Use beams of electrons, detected with photographic film. The specimen must be viewed in a vacuum therefore only dead specimen can be viewed

What is the max magnification of a light microscope?

2000x with a resolution of 200nm (nanometres)

What is the max magnification of an electron microscope?

Up to 2 million times, with a resolution of 0.2nm

What are the advantages of using electron microscopes?

They have a higher magnification

What are the advantages of using light microscopes?

The specimen can be viewed alive, they are cheaper (so can be used in state schools), they are widely accessible

How have changes in microscope technology benefited humanity?

Changes in microscope technology, including electron microscopy, have enabled us to see cell structures and organelles with more clarity and detail than in the past and increased our understanding of the role of sub-cellular structures

What are the two types and uses of the electron microscope?

Scanning electron microscopes scan an electron beam onto the specimen to collect electrons reflected from the surface to give 3D images with lower magnifications, while the transmission electron microscope is more common, used to view ultra thin sections of cells, give 2D images with high magnification and resolution

Magnification

The degree to which the size of an image is larger than the image itself (making an image bigger)

Resolution

The degree to which it is possible to distinguish between two objects that are very close together (how blurry or clear an image is)

Image size = magnification x actual size