1. Ch. 2.2
Viewing Cells

2. Magnifying Cells
Cells can not be seen with just our eyes. We need something to be able to see them magnified.

3. Early Microscopes
1st microscope made by putting 2 magnifying glasses together in a tube.

4. In the 1600’s Anton van Leeuwenhoek made a microscope with glass bead lens. He could magnify up to 270 times.

5. Modern Microscopes
A simple microscope only has one lens like a magnifying glass.
Compound light microscopes has 2 sets of lenses. The eyepiece has a lens and then there are several lenses in a tube structure.
All microscopes magnify, change the size, of the object.

6. Magnification
The powers of the eyepiece and objective lens determines the total magnification.
Example: The eyepiece magnification is 10X and the objective is 40X, the total magnification is 400x (10x times 40x)

7. Electron Microscopes
Do not use light, instead use a beam of electrons. Can magnify images to greater amount than light microscopes.

8. Scanning electron microscopes produce a 3D image of the outside of the specimen.

9. Transmission electron microscopes produce a 2D image of a sliced section of a specimen.

10. Cell Theory
With the founding of the microscope it lead to the discovery of cells. Several finding lead to the cell theory:
1. All organisms are made of one or more cells.
2. The cell is the basic unit of organization.
3. All cells come from other cells.