2. Early Microscopes At least since the ancient Romans, people had used magnifying glasses  The term lens comes from the Latin word for lentil beans, because they are a similar shape Early 1600s, the Dutch spectacle maker Zaccharias Janssen started experimenting with lenses  He put several lenses in a tube, thus creating the first “compound microscope”

3. Robert Hooke 1665, the English scientist published Micrographie Contained many microscopic illustrations of “normal” objects:  Corks  Feathers  Flies Coined the term “cell”

4. Early Microscope

5. Anton von Leeuwenhoek In the late 1600s, the Dutch merchant read and was inspired by Hooke’s Micrographie Began creating his own lenses, which had superior magnifying capability First person to discover “animalcules” - microorganisms

6. Modern Compound Microscopes Condenser lens – focuses light from the illuminator onto the specimen Iris diaphragm – regulates the amount of light that passes through the condenser lens

7. Modern Compound Microscopes Objective lenses – collect light from the specimen and magnify the image (usually 4x, 10x, or 40x) Ocular lens (eyepiece) – brings the image into focus for the eye

8. Magnification Magnification – how much a lens can increase the size of an image Objective magnification x ocular magnification = total magnification Ex: 40 x 10 = 400x

9. Resolution Resolution – the ability to see two distinct objects The purpose of microscopes is to observe details not otherwise possible with the human eye

10. Magnification AloneMagnification with Resolution

11. Magnified images are... upside-down and sdrawkcab