Microscopes Flashcards
How does a light microscope work?
Light is passed through the specimen and then through glass lenses. The lenses refract the light so that the image of the specimen is magnified and projected into the eye
Magnification definition
The ratio of image size to real size
Resolution definition
The minimum distance two points can be separated and still be distinguished as separate points
Contrast definition
The difference in brightness between the light and dark areas of an image
How many times can a light microscope effective magnify?
1,000
Light microscope maximum resolution?
0.2 micrometers
How can contrast be enhanced?
By staining or labelling cell components
Which kind of microscope is needed to view most cell organelles?
Scanning electron microscope
When was the scanning electron microscope introduced?
1950s
How does a scanning electron microscope work?
The same as a light microscope but uses electron beam instead of light
Scanning electron microscope max resolution?
0.002nm
Who was the first person to observe cells under a microscope and when?
Robert Hooke in 1665
