1. Microscope History and Development (2) Field of view and Magnification Check and go over yesterday’s HW p 140-1

2. Early Microscopes - Anton Van Leeuwenhoek The father of microscopy, Anton Van Leeuwenhoek of Holland (1632-1723). The father of microscopy, Anton Van Leeuwenhoek of Holland (1632-1723). Anton Van Leeuwenhoek was the first to see and describe bacteria (1674), yeast plants, the teeming life in a drop of water, and the circulation of blood corpuscles in capillaries. Anton Van Leeuwenhoek was the first to see and describe bacteria (1674), yeast plants, the teeming life in a drop of water, and the circulation of blood corpuscles in capillaries.

4. Robert Hooke In 1665, the English physicist Robert Hooke looked at a sliver of cork through a microscope lens and noticed some "pores" or "cells" in it. In 1665, the English physicist Robert Hooke looked at a sliver of cork through a microscope lens and noticed some "pores" or "cells" in it. Hooke was the first person to use the word "cell" to identify microscopic structures when he was describing cork. Hooke was the first person to use the word "cell" to identify microscopic structures when he was describing cork.

5. Antique microscopesAntique microscopes (link) Antique microscopes

6. Technological Advances in Microscopes

7. Compound Light Microscopes Uses light Uses light Has two lenses Has two lenses Magnification limited to 2000x (400x at LHHS) Magnification limited to 2000x (400x at LHHS)

8. Transmission Electron Microscope (TEM) Uses beams of electrons Uses beams of electrons Magnification of 2 000 000x Magnification of 2 000 000x Has two limitations: Has two limitations: Good only for thin specimens Good only for thin specimens Only dead cells can be observed Only dead cells can be observed

9. Scanning Electron Microscope (SEM) Electrons are reflected from the surface of the specimen Electrons are reflected from the surface of the specimen Produces a 3-d image Produces a 3-d image Good for the thicker specimens Good for the thicker specimens Lacks the magnification and resolution of the transmission electron microscope Lacks the magnification and resolution of the transmission electron microscope

10. Magnification Magnification = Objective lens X Ocular lens (4x, 10x, 40x)(10x)

11. Calculating the size of a specimen binder binder

12. Calculating the size of a specimen Example under med. objective Object size = Size of field of view Number of objects across field of view Object size =1.72 mm 14 Object size =0.1 mm