2. TAKE ONE OF EACH! TAKE ONE OF EACH!

3. Microscopes

4. Light Microscopes How they work: lens (es) bend light, magnifying and focusing the image Simple Microscope: has one lens Example: magnifying glass Compound Microscope: has more than one lens Example: modern microscope

5. Electron microscopes Use a beam of electrons to create the image. The beam of electrons is focused by a magnetic field. Scanning Electron Microscope (SEM) -electron beam scans surface of object -gives a picture of the outside of the object -magnifies up to 1,000,000 X Transmission Electron Microscopes (TEM) -electron beams pass through the specimen -gives a cross section view

6. What Did the Scientists See? Robert Hooke: (1665) saw the dried up boundaries of cork cells and coined the term “cell”

7. Anton van Leeuwenhoek (1670) built simple microscopes with powerful lenses and excellent resolutionbuilt simple microscopes with powerful lenses and excellent resolution made first drawings of tiny organisms he saw in pond water -- “animalicules”made first drawings of tiny organisms he saw in pond water -- “animalicules” What Did the Scientists See?

8. Cell Theory 1. All living things are composed of cells. 2. Cells are the basic unit of structure and function. 3. All cells come from preexisting cells.