Microscopes A PowerPoint Presentation by: Danielle Steward

History of Microscopes  The first vision aid was a round piece of glass that magnified objects when laid on top of them.  An Italian, Salvino D’Armate, created the first pair of eyeglasses.  In 1590, two Dutch scientists found that when they placed multiple lenses over a tube, it greatly enlarged the things inside the tube.  This lead to the creation of the compound microscope and the telescope.

 In 1665, Robert Hooke looked at a piece of cork through a microscope lens and noticed that there were “pores” or “cells.”  In 1674, Anton Van Leeuwenhoek built a simple microscope to view blood and insects.  He invented new methods of grinding and shaping the lenses to create a better magnification for the microscope.

 In 1872, Ernest Abbe created a mathematical formula called the “Abbe Sine Condition.” This formula calculated the maximum resolution a microscope could have.  In 1903, the ultra microscope was created to study objects under the wavelength of light.  In 1931, Ernst Rusko helped to invent the electron microscope which used electrons, instead of light, to view an object.

There are two configurations of microscopes. The upright and the inverted.

The Upright Microscope In the upright, the light is below the stage and the lens system is above the stage.

The Inverted Microscope The inverted microscope has the light above the stage and the lens system below the stage.

“Behind the Lens”  The simple lens of a microscope uses reflection and refraction of light to view objects.  Geometrical Optics is the science behind magnification.  Geometrical Optics helps show how to form lenses that would be more efficient in microscopes.

Geometrical Optics  Two surfaces are ground to a certain degree and they either produce a convergence or divergence of light passing through the material.

How It Works  The microscope forms an image by passing light through the material and then the light is focused onto the eyepiece and that allows you to be able to see the material magnified.

What Are They Used For Today?  Microscopes are used to visually inspect different cells such as bacteria. They are used to help find cancer cells and process diseases.  Microscopes are still used today, but more modern versions may have lasers or motors to move objects.

In the Future!  Scientists are working to find and view the structure of the smallest known molecule.  Scientists also hope to learn more about microbes and how they affect the world.

Bibliography  Davidson, Michael. “Lenses and Geometrical Optics.” Molecular Expressions.. 01 Aug Feb. 10.  “History of Microscopes.” About.com Feb. 10.  “Visualizing the Future.” Human’s Future Feb. 10.